feat: return is_autoincrement for getColumns

Spanner now supports auto-increment columns through IDENTITY columns. This change
adds support for this to the DatabaseMetaData#getColumns() method.

Author: olavloite

src/main/resources/com/google/cloud/spanner/jdbc/DatabaseMetaData_GetColumns.sql

@@ -78,7 +78,7 @@ SELECT TABLE_CATALOG AS TABLE_CAT, TABLE_SCHEMA AS TABLE_SCHEM, TABLE_NAME, COLU
   NULL AS SCOPE_SCHEMA,
   NULL AS SCOPE_TABLE,
   NULL AS SOURCE_DATA_TYPE,
-  'NO' AS IS_AUTOINCREMENT,
+  IS_IDENTITY AS IS_AUTOINCREMENT,
   CASE
     WHEN (IS_GENERATED = 'NEVER') THEN 'NO'
     ELSE 'YES'

src/main/resources/com/google/cloud/spanner/jdbc/postgresql/DatabaseMetaData_GetColumns.sql

@@ -72,7 +72,7 @@ SELECT TABLE_CATALOG AS "TABLE_CAT", TABLE_SCHEMA AS "TABLE_SCHEM", TABLE_NAME A
        NULL AS "SCOPE_SCHEMA",
        NULL AS "SCOPE_TABLE",
        NULL AS "SOURCE_DATA_TYPE",
-       'NO' AS "IS_AUTOINCREMENT",
+       IS_IDENTITY AS "IS_AUTOINCREMENT",
        CASE
            WHEN (IS_GENERATED = 'NEVER') THEN 'NO'
            ELSE 'YES'

src/test/java/com/google/cloud/spanner/jdbc/it/ITJdbcDatabaseMetaDataTest.java

@@ -118,6 +118,7 @@ private static final class Column {
     private final Integer charOctetLength;
     private final boolean computed;
     private final String defaultValue;
+    private final boolean autoIncrement;
 
     private Column(
         String name,
@@ -138,7 +139,8 @@ private Column(
           nullable,
           charOctetLength,
           false,
-          null);
+          null,
+          false);
     }
 
     private Column(
@@ -151,7 +153,8 @@ private Column(
         boolean nullable,
         Integer charOctetLength,
         boolean computed,
-        String defaultValue) {
+        String defaultValue,
+        boolean autoIncrement) {
       this.name = name;
       this.type = type;
       this.typeName = typeName;
@@ -162,14 +165,17 @@ private Column(
       this.charOctetLength = charOctetLength;
       this.computed = computed;
       this.defaultValue = defaultValue;
+      this.autoIncrement = autoIncrement;
     }
   }
 
   private static final List<Column> EXPECTED_COLUMNS =
       Arrays.asList(
           new Column("ColInt64", Types.BIGINT, "INT64", 19, null, 10, false, null),
-          new Column("ColFloat64", Types.DOUBLE, "FLOAT64", 15, 16, 2, false, null, false, "0.0"),
-          new Column("ColFloat32", Types.REAL, "FLOAT32", 15, 16, 2, false, null, false, "0.0"),
+          new Column(
+              "ColFloat64", Types.DOUBLE, "FLOAT64", 15, 16, 2, false, null, false, "0.0", false),
+          new Column(
+              "ColFloat32", Types.REAL, "FLOAT32", 15, 16, 2, false, null, false, "0.0", false),
           new Column("ColBool", Types.BOOLEAN, "BOOL", null, null, null, false, null),
           new Column(
               "ColString",
@@ -181,7 +187,8 @@ private Column(
               false,
               100,
               false,
-              "'Hello World!'"),
+              "'Hello World!'",
+              false),
           new Column(
               "ColStringMax", Types.NVARCHAR, "STRING(MAX)", 2621440, null, null, false, 2621440),
           new Column("ColBytes", Types.BINARY, "BYTES(100)", 100, null, null, false, null),
@@ -196,7 +203,8 @@ private Column(
               false,
               null,
               false,
-              "DATE '2000-01-01'"),
+              "DATE '2000-01-01'",
+              false),
           new Column("ColTimestamp", Types.TIMESTAMP, "TIMESTAMP", 35, null, null, false, null),
           new Column("ColCommitTS", Types.TIMESTAMP, "TIMESTAMP", 35, null, null, false, null),
           new Column("ColNumeric", Types.NUMERIC, "NUMERIC", 15, null, 10, false, null),
@@ -243,7 +251,10 @@ private Column(
               true,
               2621440,
               true,
-              null));
+              null,
+              false),
+          new Column(
+              "ColIdentity", Types.BIGINT, "INT64", 19, null, 10, true, null, false, null, true));
 
   @Test
   public void testGetColumns() throws SQLException {
@@ -303,6 +314,10 @@ public void testGetColumns() throws SQLException {
             assertTrue(rs.wasNull());
             assertEquals("NO", rs.getString("IS_AUTOINCREMENT"));
             assertEquals(col.computed ? "YES" : "NO", rs.getString("IS_GENERATEDCOLUMN"));
+            // TODO: Remove check when the emulator correctly returns IS_IDENTITY
+            if (!EmulatorSpannerHelper.isUsingEmulator()) {
+              assertEquals(col.autoIncrement ? "YES" : "NO", rs.getString("IS_AUTOINCREMENT"));
+            }
             assertEquals(24, rs.getMetaData().getColumnCount());
           }
           assertFalse(rs.next());

src/test/resources/com/google/cloud/spanner/jdbc/it/CreateMusicTables.sql

@@ -96,6 +96,7 @@ CREATE TABLE TableWithAllColumnTypes (
   ColJsonArray		ARRAY<JSON>,
 
   ColComputed STRING(MAX) AS (CONCAT(COALESCE(ColString, ''), ' ', COALESCE(ColStringMax, ''))) STORED,
+  ColIdentity INT64 GENERATED BY DEFAULT AS IDENTITY (BIT_REVERSED_POSITIVE),
 ) PRIMARY KEY (ColInt64)
 ;