[YSQL] ENG-4831 (#969): Enable drop cascade

Summary:
Enabled drop cascade in the parser. Added a test in TestPgDepend.
Fixed old tests for TestPgDepend.

Test Plan: Run the TestPgDepend java test.

Reviewers: mihnea

Reviewed By: mihnea

Subscribers: kannan, yql

Differential Revision: https://phabricator.dev.yugabyte.com/D6315

java/yb-pgsql/src/test/java/org/yb/pgsql/TestPgDepend.java

@@ -26,7 +26,7 @@
 import java.util.Collections;
 import java.util.List;
 
-import static org.yb.AssertionWrappers.assertEquals;
+import static org.yb.AssertionWrappers.*;
 
 @RunWith(value=YBTestRunnerNonTsanOnly.class)
 public class TestPgDepend extends BasePgSQLTest {
@@ -52,12 +52,12 @@ public void testPgDependInsertion() throws SQLException {
       // Check that we have inserted the dependency into pg_depend.
       rs = statement.executeQuery("SELECT * FROM pg_depend "
                                   + "WHERE objid=" + oidIndex + "AND refobjid=" + oidTable);
-      int rs_count = 0;
-      while(rs.next()) ++rs_count;
-      assertEquals(rs_count, 1);
+      assertTrue(rs.next());
     }
   }
-  public void testPgDependDeletion() throws SQLException {
+
+  @Test
+  public void testTableWithIndexDeletion() throws SQLException {
     createSimpleTable("test");
     try (Statement statement = connection.createStatement()) {
       // Create an Index for the table.
@@ -76,35 +76,194 @@ public void testPgDependDeletion() throws SQLException {
       // Check that we have inserted into pg_index.
       rs = statement.executeQuery("SELECT * FROM pg_index "
                                   + "WHERE indexrelid=" + oidIndex + "AND indrelid=" + oidTable);
-      int rs_count = 0;
-      while(rs.next()) ++rs_count;
-      assertEquals(rs_count, 1);
+      assertTrue(rs.next());
 
       statement.execute("DROP TABLE test");
 
       // Check that we have deleted the dependency in pg_depend.
       rs = statement.executeQuery("SELECT * FROM pg_depend "
                                   + "WHERE objid=" + oidIndex + "and refobjid=" + oidTable);
-      rs_count = 0;
-      while(rs.next()) ++rs_count;
-      assertEquals(rs_count, 0);
+      assertFalse(rs.next());
 
       // Check that we have deleted the index's entry in pg_index.
       rs = statement.executeQuery("SELECT * FROM pg_index "
                                   + "WHERE indexrelid=" + oidIndex + "AND indrelid=" + oidTable);
-      rs_count = 0;
-      while(rs.next()) ++rs_count;
-      assertEquals(rs_count, 0);
+      assertFalse(rs.next());
 
       // Check that we have deleted the index's entry in pg_class.
       rs = statement.executeQuery("SELECT * FROM pg_class WHERE relname = 'test_h'");
-      rs_count = 0;
-      while(rs.next()) ++rs_count;
-      assertEquals(rs_count, 0);
+      assertFalse(rs.next());
 
       // Check that we can create a new index with the same name.
       createSimpleTable("test");
       statement.execute("CREATE INDEX test_h on test(h)");
     }
   }
+
+  @Test
+  public void testTableWithSequenceDeletion() throws SQLException {
+    try (Statement statement = connection.createStatement()) {
+      // Create a table with serial type
+      statement.execute("CREATE TABLE test (d SERIAL)");
+
+      // Get the OID of the table.
+      ResultSet rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname='test'");
+      rs.next();
+      int oidTable = rs.getInt("oid");
+
+      int pgSequenceOid = 1259;
+
+      // Get the parent sequence's oid.
+      rs = statement.executeQuery("SELECT objid FROM pg_depend "
+                                  + "WHERE classid=" + pgSequenceOid + "AND refobjid=" + oidTable);
+
+      rs.next();
+      int oidSequence = rs.getInt("objid");
+
+      statement.execute("DROP TABLE test");
+
+      // Check that we have deleted the dependency between the sequence and the table.
+      rs = statement.executeQuery("SELECT * FROM pg_depend "
+                                  + "WHERE objid=" + oidSequence + "AND refobjid=" + oidTable);
+      assertFalse(rs.next());
+
+      // Check that we have deleted the sequence's entry from pg_class.
+      rs = statement.executeQuery("SELECT * FROM pg_class WHERE oid=" + oidSequence);
+      assertFalse(rs.next());
+
+      // Check that we have deleted the sequence's entry from pg_sequence.
+      rs = statement.executeQuery("SELECT * FROM pg_sequence WHERE seqrelid=" + oidSequence);
+      assertFalse(rs.next());
+    }
+  }
+
+  @Test
+  public void testTableWithViewDeletionWithCascade() throws SQLException {
+    createSimpleTable("test");
+    try (Statement statement = connection.createStatement()) {
+      // Create an index for the table.
+      statement.execute("CREATE INDEX test_h on test(h)");
+
+      // Create a view on the table.
+      statement.execute("CREATE VIEW test_view AS SELECT * FROM test");
+
+      // Get the OID of the table.
+      ResultSet rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test'");
+      rs.next();
+      int oidTable = rs.getInt("oid");
+
+      // Get the OID of the index.
+      rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test_h'");
+      rs.next();
+      int oidIndex = rs.getInt("oid");
+
+      // Get the OID of the view.
+      rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test_view'");
+      rs.next();
+      int oidView = rs.getInt("oid");
+
+      // Test dropping the table (without CASCADE). -- expecting an error
+      runInvalidQuery(statement, "DROP TABLE test");
+
+      // Test dropping the table (with CASCADE).
+      statement.execute("DROP TABLE test CASCADE");
+
+      // Check that we have deleted the view-table dependency in pg_depend.
+      rs = statement.executeQuery("SELECT * FROM pg_depend "
+                                  + "WHERE objid=" + oidView + "and refobjid=" + oidTable);
+      assertFalse(rs.next());
+
+      // Check that we have deleted the index-table dependency in pg_depend.
+      rs = statement.executeQuery("SELECT * FROM pg_depend "
+                                  + "WHERE objid=" + oidIndex + "and refobjid=" + oidTable);
+      assertFalse(rs.next());
+
+      // Check that we have deleted the views's entry in pg_class.
+      rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test_view'");
+      assertFalse(rs.next());
+
+      // Check that we can create a new view with the same name.
+      createSimpleTable("test");
+      statement.execute("CREATE VIEW test_view AS SELECT * FROM test");
+    }
+  }
+
+  @Test
+  public void testViewDeletionWithCascade() throws SQLException {
+    createSimpleTable("test");
+    try (Statement statement = connection.createStatement()) {
+
+      // Create a view on the table.
+      statement.execute("CREATE VIEW test_view AS SELECT * FROM test");
+
+      // Create a view on the view.
+      statement.execute("CREATE VIEW test_view_view AS SELECT * FROM test_view");
+
+      // Get the OID of test_view.
+      ResultSet rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test_view'");
+      rs.next();
+      int oidView1 = rs.getInt("oid");
+
+      // Get the OID of test_view_view;
+      rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test_view_view'");
+      rs.next();
+      int oidView2 = rs.getInt("oid");
+
+      // Test dropping test_view (without CASCADE). -- expecting an error
+      runInvalidQuery(statement, "DROP VIEW test_view");
+
+      // Test dropping test_view (with CASCADE).
+      statement.execute("DROP VIEW test_view CASCADE");
+
+      // Check that we have deleted the view-view dependency in pg_depend.
+      rs = statement.executeQuery("SELECT * FROM pg_depend "
+                                  + "WHERE objid=" + oidView2 + " AND refobjid=" + oidView1);
+      assertFalse(rs.next());
+
+      // Check that we have deleted the test_view_view's entry in pg_class.
+      rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test_view_view'");
+      assertFalse(rs.next());
+    }
+  }
+
+  @Test
+  public void testSequenceDeletionWithCascade() throws SQLException {
+    try (Statement statement = connection.createStatement()) {
+
+      // Create a sequence.
+      statement.execute("CREATE SEQUENCE seq_test START 101");
+
+      // Create a table with a column that depends on the sequence.
+      statement.execute("CREATE TABLE test (a int, b int DEFAULT nextval('seq_test'))");
+
+      // Get the OID of the sequence.
+      ResultSet rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname='seq_test'");
+      rs.next();
+      int oidSequence = rs.getInt("oid");
+
+      // Get the OID of the table.
+      rs = statement.executeQuery("SELECT oid FROM pg_class WHERE relname = 'test'");
+      rs.next();
+      int oidTable = rs.getInt("oid");
+
+      int pgTypeOid = 1247;
+
+      // Get the OID of the table column type
+      rs = statement.executeQuery("SELECT objid FROM pg_depend "
+                                  + " WHERE classid=" + pgTypeOid + " AND refobjid=" + oidSequence);
+      rs.next();
+      int oidColType = rs.getInt("objid");
+
+      // Test dropping the sequence (without CASCADE). -- expecting an error
+      runInvalidQuery(statement, "DROP SEQUENCE seq_test");
+
+      // Test dropping the sequence (with CASCADE).
+      statement.execute("DROP SEQUENCE seq_test CASCADE");
+
+      // Check that we have deleted the table column to sequence type dependency in pg_depend.
+      rs = statement.executeQuery("SELECT * FROM pg_depend "
+                                  + "WHERE objid=" + oidColType + " AND refobjid=" + oidSequence);
+      assertFalse(rs.next());
+    }
+  }
 }