Database API
APIs that store and retrieve data on the blockchain EOS.IO
Table of Contents
The data are organized according to the following broad structure:
- Scope - an account where the data is stored
- Code - the account name which has write permission
- Table - a name for the table that is being stored
- Record - a row in the table
数据是按照以下广泛的结构进行组织：
- 范围 - 存储数据的帐户 - 代码 - 具有写入权限的帐户名称 - 表格 - 正在存储的表格的名称 - 记录 - 表中的一行
Every transaction specifies the set of valid scopes that may be read and/or written to. The code that is running determines what can be written to; therefore, write operations do not allow you to specify/configure the code.
每个事务都需指定可以读取和/或写入的有效范围集合。正在运行的代码决定了可以写入的内容; 因此，写入操作不允许您指定/配置代码。
Note: Attempts to read and/or write outside the valid scope and/or code sections will cause your transaction to fail. 注意： 尝试在有效的作用域和/或代码段之外进行读取和/或写入将导致事务失败。
The database APIs assume that the first bytes of each record represent the primary and/or secondary keys followed by an arbitrary amount of data.
数据库API假设每个记录的第一个字节代表主键和/或辅助键，后面跟随着任意数量的数据。
C APIs for interfacing with the database. 与数据库交互的C API。
These methods interface with a simple table with String unique primary key and arbitrary binary data value. 这些方法与一个带有String类型的唯一主键和任意二进制数据值的简单表格交互。
int32_t store_str (account_name scope, table_name table, char *key, uint32_t keylen, char *value, uint32_t valuelen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
table - the ID/name of the table within the current scope/code context to modify
-
scope - 将要读取的帐户范围必须存在于事务范围列表中 - table - 当前范围/代码上下文中要修改的表的ID /名称
Returns 返回
1 if a new record was created, 0 if an existing record was updated 如果创建了新记录则返回１，如果现有记录被跟新了则返回0
Precondition 前提
datalen >= sizeof(uint64_t) data is a valid pointer to a range of memory at least datalen bytes long ((Name)data) stores the primary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition)
datalen >= sizeof(uint64_t) 数据是一个有效的指针，指向一个至少有datalen字节长度的内存 ((Name)data)存储主键作用域被当前事务声明 这个方法是从一个应用上下文被调用（不验证或先决条件）
Postcondition 后置条件
a record is either created or updated with the given scope and table. 一个记录是创建或更新与给定的范围和表。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t update_str (account_name scope, table_name table, char *key, uint32_t keylen, char *value, uint32_t valuelen)
Returns 返回
1 if the record was updated, 0 if no record with key was found 如果记录已更新，则返回1;如果没有找到具有密钥的记录，则返回0
int32_t load_str (account_name scope, account_name code, table_name table, char *key, uint32_t keylen, char *value, uint32_t valuelen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the stored record, should be initialized with the key to get
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围或者代码上下文中的表的ID或名称
-
data - 要复制存储的记录的位置，应该用key初始化来获取
-
datalen - 要读取的最大数据长度，必须大于sizeof(uint64_t)
Returns 返回
the number of bytes read or -1 if key was not found 读取的字节数，如果没有找到密钥，则返回-1
int32_t front_str (account_name scope, account_name code, table_name table, char *value, uint32_t valuelen)
int32_t back_str (account_name scope, account_name code, table_name table, char *value, uint32_t valuelen)
int32_t next_str (account_name scope, account_name code, table_name table, char *key, uint32_t keylen, char *value, uint32_t valuelen)
int32_t previous_str (account_name scope, account_name code, table_name table, char *key, uint32_t keylen, char *value, uint32_t valuelen)
int32_t lower_bound_str (account_name scope, account_name code, table_name table, char *key, uint32_t keylen, char *value, uint32_t valuelen)
int32_t upper_bound_str (account_name scope, account_name code, table_name table, char *key, uint32_t keylen, char *value, uint32_t valuelen)
Returns 返回
1 if the record was updated, 0 if no record with key was found 如果记录已更新，则返回1;如果没有找到具有密钥的记录，则返回0
int32_t remove_str (account_name scope, table_name table, char *key, uint32_t keylen)
Parameters 参数
- data - must point to at least 8 bytes containing primary key
- data - 必须指向包含主键的至少8个字节
Returns 返回
1 if a record was removed, and 0 if no record with key was found 如果记录被删除，则为1;如果没有找到记录，则记录为0
These methods interface with a simple table with 64 bit unique primary key and arbitrary binary data value. 这些方法与具有64位唯一主键和任意二进制数据值的简单表格进行交互。
#pragma pack(push, 1)
struct test_model {
account_name name;
unsigned char age;
uint64_t phone;
};
test_model alice{ N(alice), 20, 4234622};
test_model bob { N(bob), 15, 11932435};
test_model carol{ N(carol), 30, 545342453};
test_model dave { N(dave), 46, 6535354};
int32_t res = store_i64(currentCode(), N(test_table), &dave, sizeof(test_model));
res = store_i64(currentCode(), N(test_table), &carol, sizeof(test_model));
res = store_i64(currentCode(), N(test_table), &bob, sizeof(test_model));
res = store_i64(currentCode(), N(test_table), &alice, sizeof(test_model));
test_model alice;
alice.name = N(alice);
res = load_i64( currentCode(), currentCode(), N(test_table), &alice, sizeof(test_model) );
ASSERT(res == sizeof(test_model) && tmp.name == N(alice) && tmp.age == 20 && tmp.phone == 4234622, "load_i64");
res = front_i64( currentCode(), currentCode(), N(test_table), &tmp, sizeof(test_model) );
ASSERT(res == sizeof(test_model) && tmp.name == N(alice) && tmp.age == 20 && tmp.phone == 4234622, "front_i64 1");
res = back_i64( currentCode(), currentCode(), N(test_table), &tmp, sizeof(test_model) );
ASSERT(res == sizeof(test_model) && tmp.name == N(dave) && tmp.age == 46 && tmp.phone == 6535354, "back_i64 2");
res = previous_i64( currentCode(), currentCode(), N(test_table), &tmp, sizeof(test_model) );
ASSERT(res == sizeof(test_model) && tmp.name == N(carol) && tmp.age == 30 && tmp.phone == 545342453, "carol previous");
res = next_i64( currentCode(), currentCode(), N(test_table), &tmp, sizeof(test_model) );
ASSERT(res == sizeof(test_model) && tmp.name == N(dave) && tmp.age == 46 && tmp.phone == 6535354, "back_i64 2");
uint64_t key = N(alice);
res = remove_i64(currentCode(), N(test_table), &key);
ASSERT(res == 1, "remove alice");
test_model lb;
lb.name = N(bob);
res = lower_bound_i64( currentCode(), currentCode(), N(test_table), &lb, sizeof(test_model) );
ASSERT(res == sizeof(test_model) && lb.name == N(bob), "lower_bound_i64 bob" );
test_model ub;
ub.name = N(alice);
res = upper_bound_i64( currentCode(), currentCode(), N(test_table), &ub, sizeof(test_model) );
ASSERT(res == sizeof(test_model) && ub.age == 15 && ub.name == N(bob), "upper_bound_i64 bob" );
int32_t store_i64 (account_name scope, table_name table, const void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
table - the ID/name of the table within the current scope/code context to modify
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
table - 当前范围/代码上下文中要修改的表的ID/名称
Returns 返回
1 if a new record was created, 0 if an existing record was updated 如果创建了新记录则返回１，则在更新已有记录时则返回0
Precondition 前提
datalen >= sizeof(uint64_t) data is a valid pointer to a range of memory at least datalen bytes long ((uint64_t)data) stores the primary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition)
datalen >= sizeof(uint64_t) 数据是一个有效的指针，指向一个至少有datalen字节长度的内存 ((uint64_t)data)存储主键作用域被当前事务声明 范围是被当前交易声明的 这个方法是从一个应用上下文被调用（不验证或先决条件）
Postcondition 前提条件
a record is either created or updated with the given scope and table. 一个记录是创建或更新与给定的范围和表。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t update_i64 (account_name scope, table_name table, const void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
table - the ID/name of the table within the current scope/code context to modify
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
table - 当前范围/代码上下文中要修改的表的ID /名称
Returns 返回
1 if the record was updated, 0 if no record with key was found 如果记录已更新，则为1;如果没有找到具有密钥的记录，则为0
Precondition 前提条件
datalen >= sizeof(uint64_t) data is a valid pointer to a range of memory at least datalen bytes long ((uint64_t)data) stores the primary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition)
datalen >= sizeof(uint64_t) 数据是一个有效的指针，指向一个至少有datalen字节长度的内存 ((uint64_t)data)存储主键作用域被当前事务声明 范围是被当前交易声明的 这个方法是从一个应用上下文被调用（不验证或先决条件）
Postcondition 后置条件
a record is either created or updated with the given scope and table. 一个记录是创建或更新与给定的范围和表。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t load_i64 (account_name scope, account_name code, table_name table, void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the stored record, should be initialized with the key to get
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制存储的记录的位置，应该用key来初始化来获取
-
datalen - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if key was not found 返回读取的字节数，如果没有找到密钥，则返回-1
int32_t front_i64 (account_name scope, account_name code, table_name table, void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the front record
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制前面记录的位置
-
datalen - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到密钥，则返回-1
int32_t back_i64 (account_name scope, account_name code, table_name table, void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the back record
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制后面记录的位置
-
datalen - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
- the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到密钥，则返回-1
int32_t next_i64 (account_name scope, account_name code, table_name table, void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the next record. Should be initialized with the key to get next record.
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制下一条记录的位置。应该用key初始化以获得下一条记录。
-
datalen - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if key was not found 返回读取的字节数，如果没有找到密钥，则返回-1
int32_t previous_i64 (account_name scope, account_name code, table_name table, void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the previous record. Should be initialized with the key to get previous record.
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制上一条记录的位置。应该用key初始化以获得下一条记录。
-
datalen - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if key was not found 返回读取的字节数，如果没有找到密钥，则返回-1
int32_t lower_bound_i64 (account_name scope, account_name code, table_name table, void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the lower bound. Should be initialized with the key to find lower bound of.
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制下界的位置。应该用key来初始化找到下界。
-
datalen - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if key was not found 返回读取的字节数，如果没有找到密钥，则返回-1
int32_t upper_bound_i64 (account_name scope, account_name code, table_name table, void *data, uint32_t datalen)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the upper bound. Should be initialized with the key to find upper bound of.
-
datalen - the maximum length of data to read, must be greater than sizeof(uint64_t)
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制上界的位置。应该用key来初始化找到上界。
-
datalen - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if key was not found 返回读取的字节数，如果没有找到密钥，则返回-1
int32_t remove_i64 (account_name scope, table_name table, void *data)
Parameters 参数
-
scope - the account socpe that will be read, must exist in the transaction scopes list
-
table - the ID/name of the table withing the scope/code context to query
-
data - must point to at lest 8 bytes containing primary key
-
scope - 将被读取的帐户社会必须存在于事务范围列表中
-
table - 带查询范围/代码上下文的表的ID/名称
-
data - 必须指向至少包含主键的8个字节
Returns 返回
1 if a record was removed, and 0 if no record with key was found 如果记录被删除，则为1;如果没有找到记录，则记录为0
Interface to a database table with 128 bit primary and secondary keys and arbitary binary data value. 与128位主键和次级键以及任意二进制数据值的数据库表交互。
Parameters 参数
-
scope - the account where table data will be found
-
code - the code which owns the table
-
table - the name of the table where record is stored
-
data - a pointer to memory that is at least 32 bytes long
-
len - the length of data, must be greater than or equal to 32 bytes
-
scope - 表数据将被查到的帐户
-
code - 拥有该表的代码
-
table - 存储记录的表的名称
-
data - 指向至少32字节长的内存的指针
-
len - 数据的长度必须大于或等于32个字节
Returns 返回
the total number of bytes read or -1 for "not found" or "end" where bytes read includes 32 bytes of the key 读取的总字节数，或-1表示“not found”，或“end”，其中字节读取包括32个字节的密钥
These methods assume a database table with records of the form: 这些方法假设一个数据库表格，其格式为：
struct record { uint128 primary; uint128 secondary; ... arbitrary data ... };
You can iterate over these indicies with primary index sorting records by { primary, secondary } and the secondary index sorting records by { secondary, primary }. This means that duplicates of the primary or secondary values are allowed so long as there are no duplicates of the combination {primary, secondary}.
你可以迭代记录用{primary，secondary}排序的主索引记录和用{secondary，primary}排序的辅助索引记录。这意味着只要没有重复的{primary，secondary}组合，就允许重复的单独主键或单独辅键。
struct test_model128x2 {
uint128_t number;
uint128_t price;
uint64_t extra;
uint64_t table_name;
};
test_model128x2 alice{0, 500, N(alice), N(table_name)};
test_model128x2 bob{1, 1000, N(bob), N(table_name)};
test_model128x2 carol{2, 1500, N(carol), N(table_name)};
test_model128x2 dave{3, 2000, N(dave), N(table_name)};
int32_t res = store_i128i128(CurrentCode(), N(table_name), &alice, sizeof(test_model128x2));
res = store_i128i128(CurrentCode(), N(table_name), &bob, sizeof(test_model128x2));
ASSERT(res == 1, "db store failed");
res = store_i128i128(CurrentCode(), N(table_name), &carol, sizeof(test_model128x2));
ASSERT(res == 1, "db store failed");
res = store_i128i128(CurrentCode(), N(table_name), &dave, sizeof(test_model128x2));
ASSERT(res == 1, "db store failed");
test_model128x2 query;
query.number = 0;
res = load_primary_i128i128(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 0 && query.price == 500 && query.extra == N(alice), "load");
res = front_primary_i128i128(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 3 && query.price = 2000 && query.extra == N(dave), "front");
res = next_primary_i128i128(CurrentCode(), CurrentCode(), N(table_name), & query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 2 && query.price == 1500 && query.extra == N(carol), "next");
res = back_primary_i128i128(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 0 && query.price == 500 && query.extra == N(alice), "back");
res = previous_primary_i128i128(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 1 && query.price == 1000 && query.extra == N(bob), "previous");
query.number = 0;
res = lower_bound_primary_i128i128(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 0 && query.price == 500 && query.extra == N(alice), "lower");
res = upper_bound_primary_i128i128(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 1 && query.price == 1000 && query.extra == N(bob), "upper");
query.extra = N(bobby);
res = update_i128128(CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == sizeof(test_model128x2) && query.number == 1 & query.price == 1000 && query.extra == N(bobby), "update");
res = remove_i128128(CurrentCode(), N(table_name), &query, sizeof(test_model128x2));
ASSERT(res == 1, "remove")
int32_t load_primary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters 参数
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - the code which owns the table
-
table - the ID/name of the table within the current scope/code context to modify
-
data - location to copy the record, must be initialized with the primary key to load
-
len - length of record to copy
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 拥有该表的代码
-
table - 当前范围/代码上下文中要修改的表的ID /名称
-
data - 复制记录的位置，必须用主键进行初始化加载
-
len - 要复制的记录的长度
Returns 返回
the number of bytes read, -1 if key was not found 返回读取的字节数，如果没有找到密钥，则返回-1
Precondition 前置条件
len >= sizeof(uint128_t) data is a valid pointer to a range of memory at least datalen bytes long ((uint128_t)data) stores the primary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition)
datalen >= sizeof(uint64_t) 数据是一个有效的指针，指向一个至少有datalen字节长度的内存 ((uint128_t)data)存储主键作用域被当前事务声明 范围是被当前交易声明的 这个方法是从一个应用上下文被调用（不验证或先决条件）
Postcondition 前提条件
data will be initialized with the len bytes of record matching the key. 数据将用与键匹配的记录的len个字节进行初始化。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t front_primary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the front record of primary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 位置复制主键的前面记录
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t back_primary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the back record of primary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 位置来复制主键的后面记录
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t next_primary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the next record of primary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制主键的下一个记录的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t previous_primary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the previous record of primary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制主键的前一个记录的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t upper_bound_primary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the upper bound of a primary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制一个主键的上界的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t lower_bound_primary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the lower bound of a primary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制一个主键的下界的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t load_secondary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - the code which owns the table
- table - the ID/name of the table within the current scope/code context to modify
- data - location to copy the record, must be initialized with the secondary key to load
- len - length of record to copy
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 拥有该表的代码
- table - 当前范围/代码上下文中要修改的表的ID /名称
- data - 复制记录的位置，必须用辅助键初始化才能加载
- len - 要复制的记录的长度
Returns 返回
the number of bytes read, -1 if key was not found 返回读取的字节数，-1如果没有找到密钥
Precondition
len >= sizeof(uint128_t) data is a valid pointer to a range of memory at least datalen bytes long ((uint128_t)data) stores the secondary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition)
前提
len>=sizeof(uint128_t) 数据是指向至少datalen字节长的内存范围的有效指针 *((uint128_t *)data)存储二级密钥 范围由当前事务声明 这个方法是从一个应用的上下文（不验证或先决条件）
Postcondition 后置条件
data will be initialized with the len bytes of record matching the key. 数据将用与键匹配的记录的len字节进行初始化。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t front_secondary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the front record of secondary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制副键的前面记录的位置
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t back_secondary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
-
scope - the account scope that will be read, must exist in the transaction scopes list
-
code - identifies the code that controls write-access to the data
-
table - the ID/name of the table within the scope/code context to query
-
data - location to copy the back record of secondary key
-
len - the maximum length of data to read, must be greater than sizeof(uint64_t) 参数
-
scope - 将要读取的帐户范围必须存在于事务范围列表中
-
code - 标识控制对数据的写入访问的代码
-
table - 要查询的范围/代码上下文中表的ID /名称
-
data - 复制副键的后面记录的位置
-
len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t next_secondary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the next record of secondary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制次级秘钥对应的下一个记录的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t previous_secondary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the previous record of secondary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制次级秘钥对应的上一个记录的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t upper_bound_secondary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the upper bound of a primary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data -复制主键的上界的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t lower_bound_secondary_i128i128 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the lower bound of given secondary key; must be initialized with a key.
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data -复制主键的下界的位置; 必须用键来初始化。
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 返回读取的字节数，如果没有找到记录，则返回-1
int32_t remove_i128i128 (account_name scope, table_name table, const void *data)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- table - the ID/name of the table within the scope/code context to query
- data - must point to at lest 32 bytes containing {primary,secondary}
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 必须指向至少32个字节，包含{primary，secondary}
Returns 返回
1 if a record was removed, and 0 if no record with key was found 如果记录被删除，则为1;如果没有找到记录，则记录为0
int32_t store_i128i128 (account_name scope, table_name table, const void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- table - the ID/name of the table within the scope/code context to query
- data - must point to a at least 32 bytes containing (primary, secondary)
- len - the length of the data
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 必须指向至少32个字节，包含（主要，次要）
- len - 数据的长度
Returns 返回
1 if a new record was created, 0 if an existing record was updated 如果创建了新记录,则为１，已有记录被跟新时，则为0
int32_t update_i128i128 (account_name scope, table_name table, const void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- table - the ID/name of the table within the scope/code context to query
- data - must to a at least 32 bytes containing (primary, secondary)
- len - the length of the data
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 必须指向至少32个字节，包含（主要，次要）
- len - 数据的长度
Returns 返回
1 if the record was updated, 0 if no record with key was found 如果记录已更新，则为1;如果没有找到具有密钥的记录，则为0
Interface to a database table with 64 bit primary, secondary and tertiary keys and arbitrary binary data value. 与64位主键，次级键和三级键以及任意二进制数据值的数据库表交互。
Parameters
- scope - the account where table data will be found
- code - the code which owns the table
- table - the name of the table where record is stored
- data - a pointer to memory that is at least 32 bytes long
- len - the length of data, must be greater than or equal to 32 bytes
参数
- scope - 将查找表数据的帐户
- code - 拥有该表的代码
- table - 存储记录的表的名称
- data - 指向至少32字节长的内存的指针
- len - 数据的长度必须大于或等于32个字节
Returns 返回
the total number of bytes read or -1 for "not found" or "end" where bytes read includes 24 bytes of the key 读取的字节总数, 或-1表示“not found”或“end”，其中读取的字节包括24个字节的密钥
These methods assume a database table with records of the form: 这些方法假设一个数据库表格，其格式为：
struct record { uint64 primary; uint64 secondary; uint64 tertiary; ... arbitrary data ... };
You can iterate over these indices with primary index sorting records by { primary, secondary, tertiary }, the secondary index sorting records by { secondary, tertiary } and the tertiary index sorting records by { tertiary }. 您可以使用{primary，secondary，tertiary}的主索引排序记录，{secondary，tertiary}的次索引排序记录和{tertiary}的三级索引排序记录遍历这些索引。
struct test_model3xi64 {
uint64_t a;
uint64_t b;
uint64_t c;
uint64_t name;
};
test_model3xi64 alice{ 0, 0, 0, N(alice) };
test_model3xi64 bob{ 1, 1, 1, N(bob) };
test_model3xi64 carol{ 2, 2, 2, N(carol) };
test_model3xi64 dave{ 3, 3, 3, N(dave) };
int32_t res = store_i64i64i64(CurrentCode(), N(table_name), &alice, sizeof(test_model3xi64));
res = store_i64i64i64(CurrentCode(), N(table_name), &bob, sizeof(test_model3xi64));
res = store_i64i64i64(CurrentCode(), N(table_name), &carol, sizeof(test_model3xi64));
res = store_i64i64i64(CurrentCode(), N(table_name), &dave, sizeof(test_model3xi64));
test_model3xi64 query;
query.a = 0;
res = load_primary_i64i64i64(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model3xi64));
ASSERT(res == sizeof(test_model3xi64) && query.name == N(alice), "load");
res = front_primary_i64i64i64(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model3xi64));
ASSERT(res == sizeof(test_model3xi64) && query.name == N(dave), "front");
res = back_primary_i64i64i64(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model3xi64));
ASSERT(res == sizeof(test_model3xi64) && query.name == N(alice), "back");
res = previous_primary_i64i64i64(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model3xi64));
ASSERT(res == sizeof(test_model3xi64) && query.name == N(bob), "previous");
res = next_primary_i64i64i64(CurrentCode(), CurrentCode(), N(table_name), &query, sizeof(test_model3xi64));
ASSERT(res == sizeof(test_model3xi64) && query.name == N(alice), "next");*
int32_t load_primary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - the code which owns the table
- table - the ID/name of the table within the current scope/code context to modify
- data - location to copy the record, must be initialized with the (primary,secondary,tertiary) to load
- len - length of record to copy
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 拥有该表的代码
- table - 当前范围/代码上下文中要修改的表的ID /名称
- data - 要复制记录的位置，必须用（primary，secondary，tertiary）加载进行初始化
- len - 要复制的记录的长度
Returns 返回
the number of bytes read, -1 if key was not found 读取的字节数，如果没有找到密钥，则为-1
Precondition 前提条件
data is a valid pointer to a range of memory at least len bytes long ((uint64_t)data) stores the primary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition) 数据是一个有效指针，指向一个至少为len字节长的内存区域 *((uint64_t *)data)存储主键 范围由当前事务声明 这个方法是从一个应用的上下文（不验证或先决条件）
Postcondition 后置条件
data will be initialized with the len bytes of record matching the key. 数据将用与键匹配的记录的len字节进行初始化。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t front_primary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the front record of primary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 位置复制主键的前面记录
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t back_primary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the back record of primary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 位置来复制主键的后面记录
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t next_primary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the next record of primary key; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制主键的下一个记录的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t previous_primary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the previous record of primary key; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制主键的上一个记录的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t upper_bound_primary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the upper bound of a primary key; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制主键的上界的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t lower_bound_primary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the lower bound of primary key; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制主键的下界的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t load_secondary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - the code which owns the table
- table - the ID/name of the table within the current scope/code context to modify
- data - location to copy the record, must be initialized with the (secondary,tertiary) to load
- len - length of record to copy
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 拥有该表的代码
- table - 当前范围/代码上下文中要修改的表的ID /名称
- data - 复制记录的位置，必须用（二级，三级）加载进行初始化
- len - 要复制的记录的长度
Returns 返回
the number of bytes read, -1 if key was not found 读取的字节数，如果没有找到密钥，则返回-1
Precondition 前提条件
data is a valid pointer to a range of memory at least len bytes long ((uint64_t)data) stores the secondary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition)
数据是一个有效指针，指向一个至少为len字节长的内存区域 *((uint64_t *)data)存储二级密钥 范围由当前事务声明 这个方法是从一个应用的上下文（不验证或先决条件）
Postcondition 后置条件
data will be initialized with the len bytes of record matching the key. 数据将用与键匹配的记录的len字节进行初始化。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t front_secondary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the front record of a secondary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制次级键的前面记录的位置
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t back_secondary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the back record of secondary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制次级键的后面记录的位置
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t next_secondary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the next record; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制下一条记录的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t previous_secondary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the previous record; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制上一条记录的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t upper_bound_secondary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the upper bound of tertiary key; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制第三级键上界的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t lower_bound_secondary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the lower bound of secondary key; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制第三级键下界的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t load_tertiary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - the code which owns the table
- table - the ID/name of the table within the current scope/code context to modify
- data - location to copy the record, must be initialized with the (tertiary) to load
- len - length of record to copy
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 拥有该表的代码
- table - 当前范围/代码上下文中要修改的表的ID /名称
- data - 要复制记录的位置，必须用（tertiary）进行初始化才能加载
- len - 要复制的记录的长度
Returns 返回
the number of bytes read, -1 if key was not found 读取的字节数，如果没有找到密钥，则返回-1
Precondition 前提条件
data is a valid pointer to a range of memory at least len bytes long ((uint64_t)data) stores the tertiary key scope is declared by the current transaction this method is being called from an apply context (not validate or precondition)
数据是一个有效指针，指向一个至少为len字节长的内存区域 *((uint64_t *)data)存储第三级键 范围由当前事务声明 这个方法是从一个应用的上下文（不验证或先决条件）
Postcondition 后置条件
data will be initialized with the len bytes of record matching the key. 数据将用与键匹配的记录的len字节进行初始化。
Exceptions 异常
if called with an invalid precondition execution will be aborted 如果调用无效的前提条件执行将被中止
int32_t front_tertiary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the front record of a tertiary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制第三级键的前面记录的位置
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t back_tertiary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the back record of a tertiary key
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制第三级键的后面记录的位置
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t next_tertiary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the next record; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制下一条记录的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t previous_tertiary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the previous record; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中表的ID /名称
- data - 复制上一条记录的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t upper_bound_tertiary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the upper bound of tertiary key; must be initialized with a key value-
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中的表的ID /名称
- data - 复制第三级键的上界的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t lower_bound_tertiary_i64i64i64 (account_name scope, account_name code, table_name table, void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- code - identifies the code that controls write-access to the data
- table - the ID/name of the table within the scope/code context to query
- data - location to copy the lower bound of tertiary key; must be initialized with a key value
- len - the maximum length of data to read, must be greater than sizeof(uint64_t)
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- code - 标识控制对数据的写入访问的代码
- table - 要查询的范围/代码上下文中的表的ID /名称
- data - 复制第三级键的下界的位置; 必须用关键值初始化
- len - 要读取的最大数据长度必须大于sizeof（uint64_t）
Returns 返回
the number of bytes read or -1 if no record found 读取的字节数，如果没有找到记录，则返回-1
int32_t remove_i64i64i64 (account_name scope, table_name table, const void *data)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- table - the name of table where record is stored
- data - must point to at least 24 bytes containing {primary,secondary,tertiary}
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- table - 存储记录的表格的名称
- data - 必须指向至少24个字节，包含{primary，secondary，tertiary}
Returns 返回
1 if a record was removed, and 0 if no record with key was found 如果记录被删除，则为1;如果没有找到记录，则记录为0
int32_t store_i64i64i64 (account_name scope, table_name table, const void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- table - the name of table where record is stored
- data - must point to at least 24 bytes containing (primary,secondary,tertiary)
- len - length of the data
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- table - 存储记录的表格的名称
- data - 必须指向至少24个字节，包含（主要，次要，第三级）
- len - 数据的长度
Returns 返回
1 if a new record was created, 0 if an existing record was updated 如果创建了新记录，则为１，如果已有记录跟新了，则为０。
int32_t update_i64i64i64 (account_name scope, table_name table, const void *data, uint32_t len)
Parameters
- scope - the account scope that will be read, must exist in the transaction scopes list
- table - the name of table where record is stored
- data - must point to at least 24 bytes containing (primary,secondary,tertiary)
- len - length of the data
参数
- scope - 将要读取的帐户范围必须存在于事务范围列表中
- table - 存储记录的表格的名称
- data - 必须指向至少24个字节，包含（主要，次要，第三级）
- len - 数据的长度
Returns 返回
1 if the record was updated, 0 if no record with key was found 如果记录已更新，则为1;如果没有找到具有密钥的记录，则为0
C++ APIs for interfacing with the database, it provides a simple interface for storing any fixed-size struct as a database row. 用于连接数据库的C++ API，它提供了一个简单的接口，用于将任何固定大小的结构存储为数据库行。
This specialization of Table is for single-index tables 表的这种专门化是针对单索引表的
struct table < scope, code, table, Record, PrimaryType, void >
struct primary_index
Primary
typedef PrimaryType primary
typedef PrimaryType table < scope, code, table, Record, PrimaryType, void >::Primary
-
scope - the default account name scope that this table is located within
-
code - the code account name which has write permission to this table
-
table - a unique identifier (name) for this table
-
Record - the type of data stored in each row
-
PrimaryType - the type of the first field stored in Record
-
scope - 此表所在的默认帐户名称范围
-
code - 对此表具有写入权限的代码帐户名称
-
table - 此表的唯一标识符（名称）
-
Record - 每行存储的数据类型
-
PrimaryType - 记录中存储的第一个字段的类型
struct MyModel {
uint128_t number;
uint64_t name;
};
typedef table <N(myscope), N(mycode), N(mytable), MyModel, uint128_t> MyTable;
MyModel a { 1, N(one) };
MyModel b { 2, N(two) };
MyModel c { 3, N(three) };
MyModel d { 4, N(four) };
bool res = MyTable::store(a);
ASSERT(res, "store");
res = MyTable::store(b);
ASSERT(res, "store");
res = MyTable::store(c);
ASSERT(res, "store");
res = MyTable::store(d);
ASSERT(res, "store");
MyModel query;
res = MyTable::front(query);
ASSERT(res && query.number == 4 && query.name == N(four), "front");
res = MyTable::back(query);
ASSERT(res && query.number == 1 && query.name == N(one), "back");
res = MyTable::primary_index::previous(query);
ASSERT(res && query.number == 2 && query.name == N(two), "previous");
res = MyTable::primary_index::next(query);
ASSERT(res && query.number == 1 && query.name == N(one), "next");
query.number = 4;
res = MyTable::get(query);
ASSERT(res && query.number == 4 && query.name = N(four), "get");
query.name = N(Four);
res = MyTable.update(query);
ASSERT(res && query.number == 4 && query.name == N(Four), "update");
res = MyTable.remove(query);
ASSERT(res, "remove");
res = MyTable.get(query);
ASSERT(!res, "get of removed record");
static bool front (Record &r)
static bool table< scope, code, table, Record, PrimaryType, void >::front (Record & r)
fetches the front of the table 拿到表格的前几行
Parameters
- r - reference to hold the value
- r - 保存这个值的引用
Returns 返回
true if successfully retrieved the front 如果成功检索到前几行，则为true
static bool back (Record &r)
static bool table< scope, code, table, Record, PrimaryType, void >::back (Record & r)
fetches the back of the table 拿到表格的后几行
Parameters
- r - reference to hold the value
- r - 保存这个值的引用
Returns 返回
true if successfully retrieved the back 如果成功检索到前几行，则为true
static bool get (const PrimaryType &p, Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, void >::get (const PrimaryType &p, Record &r, uint64_t s=scope)
retrieves the record for the specified primary key 检索指定主键的记录
Parameters
- p - the primary key of the record to fetch
- r - reference of record to hold return value
- s - scope; defaults to scope of the class.
参数
- p - 要获取的记录的主键
- r - 保存返回值的记录参考
- s - 默认为该类的范围。
Returns 返回
true if get succeeds. 如果成功获取，则为true
static bool get (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, void >::get (Record & r, uint64_t s = scope)
retrieves a record based on initialized primary key value 基于初始化的主键值检索记录
Parameters
- r - reference of a record to hold return value; must be initialized to the primary key to be fetched.
- s - scope; defaults to scope of the class.
参数
- r - 保持返回值的记录的引用; 必须初始化为要获取的主键。
- s - 默认为该类的范围。
Returns 返回
true if get succeeds. 如果成功获取，则为true
static bool store (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, void >::store (const Record & r, uint64_t s = scope)
store a record to the table 将记录存储在表格中
Parameters
- r - the record to be stored.
- s - scope; defaults to scope of the class.
参数
- r - 要存储的记录。
- s - 默认为该类的范围。
Returns 返回
true if store succeeds. 如果成功存储，则为true
static bool update (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, void >::store (const Record & r, uint64_t s = scope)
store a record to the table 将记录存储在表格中
Parameters
- r - the record to be stored.
- s - scope; defaults to scope of the class.
参数
- r - 要存储的记录。
- s - 范围; 默认为该类的范围。
Returns 返回
true if store succeeds. 如果成功存储，则为true
static bool remove (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, void >::remove (const Record & r, uint64_t s = scope)
remove a record from the table. 从表中删除一条记录。
Parameters
- r - the record to be removed.
- s - scope; defaults to scope of the class.
参数
- r - 要删除的记录。
- s - 范围; 默认为该类的范围。
Returns 返回
true if remove succeeds. 如果成功删除，则为true
defines a type-safe C++ wrapper around the Database C API 定义一个对数据库C API的类型安全的C ++包装器
class table< scope, code, table, Record, PrimaryType, SecondaryType >
struct primary_index
struct secondary_index
Primary
typedef PrimaryType primary
typedef PrimaryType table< scope, code, table, Record, PrimaryType, SecondaryType >::Primary
Secondary
typedef SecondaryType secondary
typedef SecondaryType table< scope, code, table, Record, PrimaryType, SecondaryType >::Secondary
- scope - the default account name/scope that this table is located within
- code - the code account name which has write permission to this table
- table - a unique identifier (name) for this table
- Record - the type of data stored in each row
- PrimaryType - the type of the first field stored in Record
- SecondaryType - the type of the second field stored in Record
The primary and secondary indices are sorted as N-bit unsigned integers from lowest to highest.
- scope - 此表所在的默认帐户名称/范围
- code - 对此表具有写入权限的代码帐户名称
- table - 此表的唯一标识符（名称）
- Record - 每行存储的数据类型
- PrimaryType - 记录中存储的第一个字段的类型
- SecondaryType - 记录中存储的第二个字段的类型
主索引和次索引按从低到高的N位无符号整数排序
struct Model {
uint64_t primary;
uint64_t secondary;
uint64_t value;
};
typedef table <N(myscope), N(mycode), N(mytable), Model, uint64_t, uint64_t> MyTable;
Model a { 1, 11, N(first) };
Model b { 2, 22, N(second) };
Model c { 3, 33, N(third) };
Model d { 4, 44, N(fourth) };
bool res = MyTable::store(a);
ASSERT(res, "store");
res = MyTable::store(b);
ASSERT(res, "store");
res = MyTable::store(c);
ASSERT(res, "store");
res = MyTable::store(d);
ASSERT(res, "store");
Model query;
res = MyTable::primary_index::get(1, query);
ASSERT(res && query.primary == 1 && query.value == N(first), "first");
res = MyTable::primary_index::front(query);
ASSERT(res && query.primary == 4 && query.value == N(fourth), "front");
res = MyTable::primary_index::back(query);
ASSERT(res && query.primary == 1 && query.value == N(first), "back");
res = MyTable::primary_index::previous(query);
ASSERT(res && query.primary == 2 && query.value == N(second), "previous");
res = MyTable::primary_index::next(query);
ASSERT(res && query.primary == 1 && query.value == N(first), "first");
res = MyTable::secondary_index::get(11, query);
ASSERT(res && query.primary == 11 && query.value == N(first), "first");
res = MyTable::secondary_index::front(query);
ASSERT(res && query.secondary == 44 && query.value == N(fourth), "front");
res = MyTable::secondary_index::back(query);
ASSERT(res && query.secondary == 11 && query.value == N(first), "back");
res = MyTable::secondary_index::previous(query);
ASSERT(res && query.secondary == 22 && query.value == N(second), "previous");
res = MyTable::secondary_index::next(query);
ASSERT(res && query.secondary == 11 && query.value == N(first), "first");
res = MyTable::remove(query);
ASSERT(res, "remove");
res = MyTable::get(query);
ASSERT(!res, "not found already removed");
static bool get (const PrimaryType &p, Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::get(const PrimaryType & p, Record & r, uint64_t s = scope)
Parameters
- p - reference to primary key to retrieve
- r - reference to a record to load the value to.
- s - account scope. default is current scope of the class
参数
- p - 要检索的主键的引用
- r - 引用一个记录来加载值。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool store (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::store (const Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to store.
- s - account scope. default is current scope of the class
参数
- r - 引用要存储的记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful store.
返回
如果成功存储则返回true
static bool update (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::update (const Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to update.
- s - account scope. default is current scope of the class
参数
- r - 引用要更新的记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful update.
返回
如果成功跟新则返回true
static bool remove (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::remove (const Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to remove.
- s - account scope. default is current scope of the class
参数
- r - 引用要删除的记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful remove.
返回
如果成功删除则返回true
The Primary Index
table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index Struct Reference
static bool front (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::front (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to store the front record based on primary index.
- s - account scope. default is current scope of the class
参数
- r - 引用记录来存储基于主索引的前端记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool back (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::back (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to store the back record based on primary index.
- s - account scope. default is current scope of the class
参数
- r - 引用记录来存储基于主索引的后备记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool next (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::next (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to store next value; must be initialized with current.
- s - account scope. default is current scope of the class
参数
- r - 引用记录来存储下一个值; 必须在当前初始化。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool previous (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::previous (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to store previous value; must be initialized with current.
- s - account scope. default is current scope of the class
参数
- r - 引用记录来存储上一个值; 必须在当前初始化。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool get (const PrimaryType &p, Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::get (const PrimaryType & p, Record & r, uint64_t s = scope)
Parameters
- p - reference to primary key to load; must be initialized with a value;
- r - reference to a record to load the value to.
- s - account scope. default is current scope of the class
参数
- p - 加载主键的引用; 必须用值来初始化;
- r - 引用一个记录来加载值。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool lower_bound (const PrimaryType &p, Record &r)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::lower_bound (const PrimaryType & p, Record & r )
Parameters
- p - reference to primary key to get the lower bound of; must be initialized with a value;
- r - reference to a record to load the value to.
- s - account scope. default is current scope of the class
参数
- p - 主键获取下界的参考; 必须用值来初始化;
- r - 引用一个记录来加载值。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool upper_bound (const PrimaryType &p, Record &r)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::upper_bound (const PrimaryType & p, Record & r )
Parameters
- p - reference to primary key to get the upper bound of; must be initialized with a value;
- r - reference to a record to load the value to.
- s - account scope. default is current scope of the class
参数
- p - 主键获取上限的引用; 必须用值来初始化;
- r - 引用一个记录来加载值。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool remove (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::primary_index::remove (const Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to remove from table;
- s - account scope. default is current scope of the class
参数
- r - 引用要从表中删除的记录;
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successfully removed;
返回
如果成功删除则为true;
The Secondary Index.
table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index Struct Reference
static bool front (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::front (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to store the front record based on secondary index.
- s - account scope. default is current scope of the class
参数
- r - 引用记录来存储基于二级索引的前端记录。
- s - 账户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool back (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::back (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to store the back record based on secondary index.
- s - account scope. default is current scope of the class
参数
- r - 引用一条记录来存储基于二级索引的后退记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool next (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::next (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to return the next record .
- s - account scope. default is current scope of the class
参数
- r - 引用一条记录来返回下一条记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool previous (Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::previous (Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to return the previous record.
- s - account scope. default is current scope of the class
参数
- r - 引用一条记录来返回上一条记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool get (const SecondaryType &p, Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::get (const SecondaryType & p, Record & r, uint64_t s = scope)
Parameters
- p - reference to secondary index key
- r - reference to record to hold the value
- s - account scope. default is current scope of the class
参数
- p - 二级索引键的引用
- r - 引用记录来保存值
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool lower_bound (const SecondaryType &p, Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::lower_bound (const SecondaryType & p, Record & r, uint64_t s = scope)
Parameters
- p - reference to secondary key to get the lower bound of; must be initialized with a value;
- r - reference to a record to load the value to.
- s - account scope. default is current scope of the class
参数
- p - 引用次级键得到下界; 必须用值来初始化;
- r - 引用一个记录来加载值。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool upper_bound (const SecondaryType &p, Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::upper_bound (const SecondaryType & p, Record & r, uint64_t s = scope)
Parameters
- p - reference to secondary key to get the upper bound of; must be initialized with a value;
- r - reference to a record to load the value to.
- s - account scope. default is current scope of the class
参数
- p - 引用次级键来获得上界; 必须用值来初始化;
- r - 引用一个记录来加载值。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successful read.
返回
如果成功读取则返回true
static bool remove (const Record &r, uint64_t s=scope)
static bool table< scope, code, table, Record, PrimaryType, SecondaryType >::secondary_index::remove (const Record & r, uint64_t s = scope)
Parameters
- r - reference to a record to be removed.
- s - account scope. default is current scope of the class
参数
- r - 引用要删除的记录。
- s - 帐户范围。 默认是该类的当前范围
Returns
true if successfully removed.
返回
如果成功删除则返回true