Add filtered index support for SQLite

sjp · Jul 14, 2022 · fd00c89 · fd00c89
1 parent 7f6ab0d
commit fd00c89
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Showing 4 changed files with 73 additions and 1 deletion.
diff --git a/....Schematic.Sqlite.Tests/Integration/SqliteRelationalDatabaseTableProviderTests.Indexes.cs b/....Schematic.Sqlite.Tests/Integration/SqliteRelationalDatabaseTableProviderTests.Indexes.cs
@@ -1,6 +1,7 @@
 using System.Linq;
 using System.Threading.Tasks;
 using NUnit.Framework;
+using SJP.Schematic.Tests.Utilities;
 
 namespace SJP.Schematic.Sqlite.Tests.Integration;
 
@@ -96,4 +97,18 @@ public async Task Indexes_WhenGivenTableWithUniqueIndex_ReturnsIndexWithIsUnique
 
         Assert.That(index.IsUnique, Is.True);
     }
+
+    [Test]
+    public async Task Indexes_WhenGivenTableWithFilteredIndexes_ReturnsIndexWithFilteredDefinition()
+    {
+        var table = await GetTableAsync("table_test_table_38").ConfigureAwait(false);
+        var index1 = table.Indexes.Single(i => i.Name.LocalName == "ix_test_table_38_1");
+        var index2 = table.Indexes.Single(i => i.Name.LocalName == "ix_test_table_38_2");
+
+        Assert.Multiple(() =>
+        {
+            Assert.That(index1.FilterDefinition, OptionIs.None);
+            Assert.That(index2.FilterDefinition.UnwrapSome(), Is.EqualTo("where test_column_2 < 100 and test_column_2 > 3"));
+        });
+    }
 }
diff --git a/src/SJP.Schematic.Sqlite.Tests/Integration/SqliteRelationalDatabaseTableProviderTests.cs b/src/SJP.Schematic.Sqlite.Tests/Integration/SqliteRelationalDatabaseTableProviderTests.cs
@@ -230,6 +230,14 @@ test_column_3 int generated always as (test_column_1 * test_column_1 * test_colu
     test_column_4 int constraint computed_col_constraint as (test_column_1 * test_column_1 * test_column_1 * test_column_1) virtual
 )", CancellationToken.None).ConfigureAwait(false);
 
+        await DbConnection.ExecuteAsync(@"
+create table table_test_table_38 (
+    test_column_1 int not null,
+    test_column_2 int not null
+)", CancellationToken.None).ConfigureAwait(false);
+        await DbConnection.ExecuteAsync("create index ix_test_table_38_1 on table_test_table_38 (test_column_1)", CancellationToken.None).ConfigureAwait(false);
+        await DbConnection.ExecuteAsync("create index ix_test_table_38_2 on table_test_table_38 (test_column_2) where test_column_2 < 100 and test_column_2 > 3", CancellationToken.None).ConfigureAwait(false);
+
         await DbConnection.ExecuteAsync("create table trigger_test_table_1 (table_id integer primary key not null)", CancellationToken.None).ConfigureAwait(false);
         await DbConnection.ExecuteAsync("create table trigger_test_table_2 (table_id integer primary key not null)", CancellationToken.None).ConfigureAwait(false);
         await DbConnection.ExecuteAsync(@"create trigger trigger_test_table_1_trigger_1

diff --git a/src/SJP.Schematic.Sqlite/Queries/GetIndexDefinition.cs b/src/SJP.Schematic.Sqlite/Queries/GetIndexDefinition.cs
@@ -0,0 +1,25 @@
+using System;
+using SJP.Schematic.Core;
+using SJP.Schematic.Core.Extensions;
+
+namespace SJP.Schematic.Sqlite.Queries;
+
+internal static class GetIndexDefinition
+{
+    internal sealed record Query
+    {
+        public string TableName { get; init; } = default!;
+
+        public string IndexName { get; init; } = default!;
+    }
+
+    internal static string Sql(IDatabaseDialect dialect, string schemaName)
+    {
+        if (dialect == null)
+            throw new ArgumentNullException(nameof(dialect));
+        if (schemaName.IsNullOrWhiteSpace())
+            throw new ArgumentNullException(nameof(schemaName));
+
+        return $"select sql from { dialect.QuoteIdentifier(schemaName) }.sqlite_master where type = 'index' and tbl_name = @{ nameof(Query.TableName) } and name = @{ nameof(Query.IndexName) }";
+    }
+}
diff --git a/src/SJP.Schematic.Sqlite/SqliteRelationalDatabaseTableProvider.cs b/src/SJP.Schematic.Sqlite/SqliteRelationalDatabaseTableProvider.cs
@@ -400,7 +400,31 @@ private async Task<IReadOnlyCollection<IDatabaseIndex>> LoadIndexesAsyncCore(Ide
                 .Select(i => columnLookup[i.name!])
                 .ToList();
 
-            var index = new SqliteDatabaseIndex(indexList.name, indexList.unique, indexColumns, includedColumns, Option<string>.None);
+            var indexSchema = await DbConnection.ExecuteScalarAsync<string>(
+                GetIndexDefinition.Sql(Dialect, tableName.Schema!),
+                new GetIndexDefinition.Query { TableName = tableName.LocalName, IndexName = indexList.name },
+                cancellationToken
+            ).ConfigureAwait(false);
+
+            var filterDefinition = Option<string>.None;
+            if (indexSchema != null)
+            {
+                var tokens = Tokenizer.TryTokenize(indexSchema);
+                if (tokens.HasValue)
+                {
+                    var whereToken = tokens.Value.FirstOrDefault(t => t.Kind == SqliteToken.Where);
+                    if (whereToken.Kind == SqliteToken.Where)
+                    {
+                        var location = whereToken.Position.Absolute;
+                        var definition = indexSchema[location..];
+                        filterDefinition = !definition.IsNullOrWhiteSpace()
+                            ? Option<string>.Some(definition)
+                            : Option<string>.None;
+                    }
+                }
+            }
+
+            var index = new SqliteDatabaseIndex(indexList.name, indexList.unique, indexColumns, includedColumns, filterDefinition);
             result.Add(index);
         }