fix: findColumn is case-sensitive for unquoted identifier (#2261)

* fix: findColumn is case-sensitive for unquoted identifier

* Addressed comments

Author: sakthivelmanii

src/main/java/com/google/cloud/spanner/jdbc/JdbcDatabaseMetaData.java

@@ -187,7 +187,7 @@ public boolean storesUpperCaseIdentifiers() {
 
   @Override
   public boolean storesLowerCaseIdentifiers() {
-    return false;
+    return connection.getDialect() == Dialect.POSTGRESQL;
   }
 
   @Override

src/test/java/com/google/cloud/spanner/jdbc/JdbcDatabaseMetaDataTest.java

@@ -61,6 +61,7 @@ public static Object[] data() {
   @Test
   public void testTrivialMethods() throws SQLException {
     JdbcConnection connection = mock(JdbcConnection.class);
+    when(connection.getDialect()).thenReturn(dialect);
     DatabaseMetaData meta = new JdbcDatabaseMetaData(connection);
     assertTrue(meta.allProceduresAreCallable());
     assertTrue(meta.allTablesAreSelectable());
@@ -132,7 +133,11 @@ public void testTrivialMethods() throws SQLException {
     assertTrue(meta.nullPlusNonNullIsNull());
     assertFalse(meta.isCatalogAtStart());
     assertEquals(connection.isReadOnly(), meta.isReadOnly());
-    assertFalse(meta.storesLowerCaseIdentifiers());
+    if (dialect == Dialect.POSTGRESQL) {
+      assertTrue(meta.storesLowerCaseIdentifiers());
+    } else {
+      assertFalse(meta.storesLowerCaseIdentifiers());
+    }
     assertFalse(meta.storesLowerCaseQuotedIdentifiers());
     assertTrue(meta.storesMixedCaseIdentifiers());
     assertTrue(meta.storesMixedCaseQuotedIdentifiers());