From 6f6ccc1e71de999c133341e25ed364948fb6d4fb Mon Sep 17 00:00:00 2001
From: Jiefan Li <jiefli@linkedin.com>
Date: Wed, 31 Aug 2022 07:40:19 -0700
Subject: [PATCH] Coral-Schema: Add support for LogicalValues

---
 .../coral/schema/avro/RelToAvroSchemaConverter.java    |  6 ++++--
 .../schema/avro/ViewToAvroSchemaConverterTests.java    |  7 +++++++
 .../resources/testSelectWithoutBaseTable-expected.avsc | 10 ++++++++++
 3 files changed, 21 insertions(+), 2 deletions(-)
 create mode 100644 coral-schema/src/test/resources/testSelectWithoutBaseTable-expected.avsc

diff --git a/coral-schema/src/main/java/com/linkedin/coral/schema/avro/RelToAvroSchemaConverter.java b/coral-schema/src/main/java/com/linkedin/coral/schema/avro/RelToAvroSchemaConverter.java
index 87690b29e..24557d9ce 100644
--- a/coral-schema/src/main/java/com/linkedin/coral/schema/avro/RelToAvroSchemaConverter.java
+++ b/coral-schema/src/main/java/com/linkedin/coral/schema/avro/RelToAvroSchemaConverter.java
@@ -197,8 +197,10 @@ public RelNode visit(TableFunctionScan tableFunctionScan) {
 
     @Override
     public RelNode visit(LogicalValues logicalValues) {
-      // TODO: implement this method
-      return super.visit(logicalValues);
+      RelNode relNode = super.visit(logicalValues);
+      schemaMap.put(logicalValues,
+          RelDataTypeToAvroType.relDataTypeToAvroTypeNonNullable(logicalValues.getRowType(), "literalvalue"));
+      return relNode;
     }
 
     @Override
diff --git a/coral-schema/src/test/java/com/linkedin/coral/schema/avro/ViewToAvroSchemaConverterTests.java b/coral-schema/src/test/java/com/linkedin/coral/schema/avro/ViewToAvroSchemaConverterTests.java
index dd381f839..4b5601aff 100644
--- a/coral-schema/src/test/java/com/linkedin/coral/schema/avro/ViewToAvroSchemaConverterTests.java
+++ b/coral-schema/src/test/java/com/linkedin/coral/schema/avro/ViewToAvroSchemaConverterTests.java
@@ -1024,5 +1024,12 @@ public void testLowercaseSchema() {
     Assert.assertEquals(actualSchema.toString(true), TestUtils.loadSchema("testLowercaseSchema-expected.avsc"));
   }
 
+  @Test
+  public void testSelectWithoutBaseTable() {
+    final ViewToAvroSchemaConverter viewToAvroSchemaConverter = ViewToAvroSchemaConverter.create(hiveMetastoreClient);
+    final Schema actualSchema = viewToAvroSchemaConverter.toAvroSchema("SELECT 1 intCol");
+
+    Assert.assertEquals(actualSchema.toString(true), TestUtils.loadSchema("testSelectWithoutBaseTable-expected.avsc"));
+  }
   // TODO: add more unit tests
 }
diff --git a/coral-schema/src/test/resources/testSelectWithoutBaseTable-expected.avsc b/coral-schema/src/test/resources/testSelectWithoutBaseTable-expected.avsc
new file mode 100644
index 000000000..ed51a5205
--- /dev/null
+++ b/coral-schema/src/test/resources/testSelectWithoutBaseTable-expected.avsc
@@ -0,0 +1,10 @@
+{
+  "type" : "record",
+  "name" : "literalvalue",
+  "namespace" : "rel_avro",
+  "fields" : [ {
+    "name" : "intCol",
+    "type" : [ "null", "int" ],
+    "doc" : "Field created from view literal with value: 1"
+  } ]
+}
\ No newline at end of file