Fix SHOW CREATE SCHEMA for connectors

Before the change, SHOW CREATE SCHEMA did not work for almost all
connectors (except maybe for Hive, Iceberg, Blackhole and Memory).

core/trino-spi/src/main/java/io/trino/spi/connector/ConnectorMetadata.java

@@ -662,15 +662,15 @@ default Optional<ConnectorViewDefinition> getView(ConnectorSession session, Sche
      */
     default Map<String, Object> getSchemaProperties(ConnectorSession session, CatalogSchemaName schemaName)
     {
-        throw new TrinoException(NOT_SUPPORTED, "This connector does not support schema properties");
+        return Map.of();
     }
 
     /**
      * Get the schema properties for the specified schema.
      */
     default Optional<TrinoPrincipal> getSchemaOwner(ConnectorSession session, CatalogSchemaName schemaName)
     {
-        throw new TrinoException(NOT_SUPPORTED, "This connector does not support schema ownership");
+        return Optional.empty();
     }
 
     /**

plugin/trino-blackhole/src/main/java/io/trino/plugin/blackhole/BlackHoleMetadata.java

@@ -103,12 +103,6 @@ public Optional<TrinoPrincipal> getSchemaOwner(ConnectorSession session, Catalog
         return Optional.empty();
     }
 
-    @Override
-    public Map<String, Object> getSchemaProperties(ConnectorSession session, CatalogSchemaName schemaName)
-    {
-        return ImmutableMap.of();
-    }
-
     @Override
     public ConnectorTableHandle getTableHandle(ConnectorSession session, SchemaTableName tableName)
     {

plugin/trino-hive/src/test/java/io/trino/plugin/hive/TestHiveConnectorTest.java

@@ -819,6 +819,7 @@ public void testViewAuthorizationForRole()
     }
 
     @Test
+    @Override
     public void testShowCreateSchema()
     {
         Session admin = Session.builder(getSession())

plugin/trino-iceberg/src/test/java/io/trino/plugin/iceberg/AbstractTestIcebergConnectorTest.java

@@ -194,6 +194,7 @@ public void testRenameTable()
     }
 
     @Test
+    @Override
     public void testShowCreateSchema()
     {
         assertThat(computeActual("SHOW CREATE SCHEMA tpch").getOnlyValue().toString())

plugin/trino-memory/src/main/java/io/trino/plugin/memory/MemoryMetadata.java

@@ -131,12 +131,6 @@ public Optional<TrinoPrincipal> getSchemaOwner(ConnectorSession session, Catalog
         return Optional.empty();
     }
 
-    @Override
-    public Map<String, Object> getSchemaProperties(ConnectorSession session, CatalogSchemaName schemaName)
-    {
-        return ImmutableMap.of();
-    }
-
     @Override
     public synchronized ConnectorTableHandle getTableHandle(ConnectorSession session, SchemaTableName schemaTableName)
     {

testing/trino-testing/src/main/java/io/trino/testing/AbstractTestDistributedQueries.java

@@ -1090,6 +1090,14 @@ public void testWrittenStats()
         assertUpdate("DROP TABLE " + tableName);
     }
 
+    @Test
+    public void testShowCreateSchema()
+    {
+        String schemaName = getSession().getSchema().orElseThrow();
+        assertThat((String) computeScalar("SHOW CREATE SCHEMA " + schemaName))
+                .isEqualTo(format("CREATE SCHEMA %s.%s", getSession().getCatalog().orElseThrow(), schemaName));
+    }
+
     @Test
     public void testCreateSchema()
     {
@@ -1101,6 +1109,8 @@ public void testCreateSchema()
         assertThat(computeActual("SHOW SCHEMAS").getOnlyColumnAsSet()).doesNotContain(schemaName);
         assertUpdate("CREATE SCHEMA " + schemaName);
         assertThat(computeActual("SHOW SCHEMAS").getOnlyColumnAsSet()).contains(schemaName);
+        assertThat((String) computeScalar("SHOW CREATE SCHEMA " + schemaName))
+                .startsWith(format("CREATE SCHEMA %s.%s", getSession().getCatalog().orElseThrow(), schemaName));
         assertQueryFails("CREATE SCHEMA " + schemaName, format("line 1:1: Schema '.*\\.%s' already exists", schemaName));
         assertUpdate("DROP SCHEMA " + schemaName);
         assertQueryFails("DROP SCHEMA " + schemaName, format("line 1:1: Schema '.*\\.%s' does not exist", schemaName));