sql: parse and recognize ALTER SCHEMA and DROP SCHEMA

Touches #50880.
Touches #50884.

This commit adds the boilerplate for adding the `ALTER SCHEMA` and `DROP
SCHEMA` statements.

Release note: None

docs/generated/sql/bnf/drop_stmt.bnf

@@ -4,6 +4,7 @@ drop_stmt ::=
 	| drop_table_stmt
 	| drop_view_stmt
 	| drop_sequence_stmt
+	| drop_schema_stmt
 	| drop_type_stmt
 	| drop_role_stmt
 	| drop_schedule_stmt

docs/generated/sql/bnf/stmt_block.bnf

@@ -310,6 +310,7 @@ alter_ddl_stmt ::=
 	| alter_database_stmt
 	| alter_range_stmt
 	| alter_partition_stmt
+	| alter_schema_stmt
 	| alter_type_stmt
 
 alter_role_stmt ::=
@@ -406,6 +407,7 @@ drop_ddl_stmt ::=
 	| drop_table_stmt
 	| drop_view_stmt
 	| drop_sequence_stmt
+	| drop_schema_stmt
 	| drop_type_stmt
 
 drop_role_stmt ::=
@@ -1064,6 +1066,9 @@ alter_range_stmt ::=
 alter_partition_stmt ::=
 	alter_zone_partition_stmt
 
+alter_schema_stmt ::=
+	'ALTER' 'SCHEMA' schema_name 'RENAME' 'TO' schema_name
+
 alter_type_stmt ::=
 	'ALTER' 'TYPE' type_name 'ADD' 'VALUE' 'SCONST' opt_add_val_placement
 	| 'ALTER' 'TYPE' type_name 'ADD' 'VALUE' 'IF' 'NOT' 'EXISTS' 'SCONST' opt_add_val_placement
@@ -1203,6 +1208,10 @@ drop_sequence_stmt ::=
 	'DROP' 'SEQUENCE' table_name_list opt_drop_behavior
 	| 'DROP' 'SEQUENCE' 'IF' 'EXISTS' table_name_list opt_drop_behavior
 
+drop_schema_stmt ::=
+	'DROP' 'SCHEMA' schema_name_list opt_drop_behavior
+	| 'DROP' 'SCHEMA' 'IF' 'EXISTS' schema_name_list opt_drop_behavior
+
 drop_type_stmt ::=
 	'DROP' 'TYPE' type_name_list opt_drop_behavior
 	| 'DROP' 'TYPE' 'IF' 'EXISTS' type_name_list opt_drop_behavior
@@ -1455,6 +1464,9 @@ alter_zone_partition_stmt ::=
 	| 'ALTER' 'PARTITION' partition_name 'OF' 'INDEX' table_index_name set_zone_config
 	| 'ALTER' 'PARTITION' partition_name 'OF' 'INDEX' table_name '@' '*' set_zone_config
 
+schema_name ::=
+	name
+
 type_name ::=
 	db_object_name
 
@@ -1463,9 +1475,6 @@ opt_add_val_placement ::=
 	| 'AFTER' 'SCONST'
 	| 
 
-schema_name ::=
-	name
-
 opt_with ::=
 	'WITH'
 	| 
@@ -1645,6 +1654,9 @@ table_index_name_list ::=
 table_name_list ::=
 	( table_name ) ( ( ',' table_name ) )*
 
+schema_name_list ::=
+	( schema_name ) ( ( ',' schema_name ) )*
+
 type_name_list ::=
 	( type_name ) ( ( ',' type_name ) )*
 

pkg/sql/alter_schema.go

@@ -0,0 +1,39 @@
+// Copyright 2020 The Cockroach Authors.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package sql
+
+import (
+	"context"
+
+	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
+	"github.com/cockroachdb/cockroach/pkg/util/errorutil/unimplemented"
+	"github.com/cockroachdb/errors"
+)
+
+type alterSchemaNode struct {
+	n *tree.AlterSchema
+}
+
+// Use to satisfy the linter.
+var _ planNode = &alterSchemaNode{n: nil}
+
+func (p *planner) AlterSchema(ctx context.Context, n *tree.AlterSchema) (planNode, error) {
+	return nil, unimplemented.NewWithIssue(50880, "ALTER SCHEMA")
+}
+
+func (n *alterSchemaNode) startExec(params runParams) error {
+	return errors.AssertionFailedf("unimplemented")
+}
+
+func (n *alterSchemaNode) Next(params runParams) (bool, error) { return false, nil }
+func (n *alterSchemaNode) Values() tree.Datums                 { return tree.Datums{} }
+func (n *alterSchemaNode) Close(ctx context.Context)           {}
+func (n *alterSchemaNode) ReadingOwnWrites()                   {}

pkg/sql/drop_schema.go

@@ -0,0 +1,39 @@
+// Copyright 2020 The Cockroach Authors.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package sql
+
+import (
+	"context"
+
+	"github.com/cockroachdb/cockroach/pkg/sql/sem/tree"
+	"github.com/cockroachdb/cockroach/pkg/util/errorutil/unimplemented"
+	"github.com/cockroachdb/errors"
+)
+
+type dropSchemaNode struct {
+	n *tree.DropSchema
+}
+
+// Use to satisfy the linter.
+var _ planNode = &dropSchemaNode{n: nil}
+
+func (p *planner) DropSchema(ctx context.Context, n *tree.DropSchema) (planNode, error) {
+	return nil, unimplemented.NewWithIssue(50884, "DROP SCHEMA")
+}
+
+func (n *dropSchemaNode) startExec(params runParams) error {
+	return errors.AssertionFailedf("unimplemented")
+}
+
+func (n *dropSchemaNode) Next(params runParams) (bool, error) { return false, nil }
+func (n *dropSchemaNode) Values() tree.Datums                 { return tree.Datums{} }
+func (n *dropSchemaNode) Close(ctx context.Context)           {}
+func (n *dropSchemaNode) ReadingOwnWrites()                   {}

pkg/sql/logictest/testdata/logic_test/schema

@@ -102,3 +102,9 @@ CREATE TEMP TABLE myschema.tmp (x int)
 # We should error out trying to modify any virtual schemas.
 statement error pq: schema cannot be modified: "pg_catalog"
 CREATE TABLE pg_catalog.bad (x int)
+
+statement error pq: unimplemented: DROP SCHEMA
+DROP SCHEMA myschema
+
+statement error pq: unimplemented: ALTER SCHEMA
+ALTER SCHEMA myschema RENAME TO yourschema

pkg/sql/opaque.go

@@ -49,6 +49,8 @@ func buildOpaque(
 	switch n := stmt.(type) {
 	case *tree.AlterIndex:
 		plan, err = p.AlterIndex(ctx, n)
+	case *tree.AlterSchema:
+		plan, err = p.AlterSchema(ctx, n)
 	case *tree.AlterTable:
 		plan, err = p.AlterTable(ctx, n)
 	case *tree.AlterTableSetSchema:
@@ -93,6 +95,8 @@ func buildOpaque(
 		plan, err = p.DropIndex(ctx, n)
 	case *tree.DropRole:
 		plan, err = p.DropRole(ctx, n)
+	case *tree.DropSchema:
+		plan, err = p.DropSchema(ctx, n)
 	case *tree.DropTable:
 		plan, err = p.DropTable(ctx, n)
 	case *tree.DropType:
@@ -169,6 +173,7 @@ func buildOpaque(
 func init() {
 	for _, stmt := range []tree.Statement{
 		&tree.AlterIndex{},
+		&tree.AlterSchema{},
 		&tree.AlterTable{},
 		&tree.AlterTableSetSchema{},
 		&tree.AlterType{},
@@ -190,6 +195,7 @@ func init() {
 		&tree.Discard{},
 		&tree.DropDatabase{},
 		&tree.DropIndex{},
+		&tree.DropSchema{},
 		&tree.DropTable{},
 		&tree.DropType{},
 		&tree.DropView{},

pkg/sql/parser/help_test.go

@@ -69,6 +69,10 @@ func TestContextualHelp(t *testing.T) {
 		{`ALTER SEQUENCE blah RENAME ??`, `ALTER SEQUENCE`},
 		{`ALTER SEQUENCE blah RENAME TO blih ??`, `ALTER SEQUENCE`},
 
+		{`ALTER SCHEMA ??`, `ALTER SCHEMA`},
+		{`ALTER SCHEMA x RENAME ??`, `ALTER SCHEMA`},
+		{`ALTER SCHEMA x OWNER ??`, `ALTER SCHEMA`},
+
 		{`ALTER USER IF ??`, `ALTER ROLE`},
 		{`ALTER USER foo WITH PASSWORD ??`, `ALTER ROLE`},
 
@@ -182,6 +186,8 @@ func TestContextualHelp(t *testing.T) {
 		{`DROP SCHEDULE ???`, `DROP SCHEDULES`},
 		{`DROP SCHEDULES ???`, `DROP SCHEDULES`},
 
+		{`DROP SCHEMA ??`, `DROP SCHEMA`},
+
 		{`EXPLAIN (??`, `EXPLAIN`},
 		{`EXPLAIN SELECT 1 ??`, `SELECT`},
 		{`EXPLAIN INSERT INTO xx (SELECT 1) ??`, `INSERT`},

pkg/sql/parser/parse_test.go

@@ -356,6 +356,13 @@ func TestParse(t *testing.T) {
 		{`CREATE TYPE a.b AS ENUM ('a', 'b', 'c')`},
 		{`CREATE TYPE a.b.c AS ENUM ('a', 'b', 'c')`},
 
+		{`DROP SCHEMA a`},
+		{`DROP SCHEMA a, b`},
+		{`DROP SCHEMA IF EXISTS a, b, c`},
+		{`DROP SCHEMA IF EXISTS a, b CASCADE`},
+		{`DROP SCHEMA IF EXISTS a, b RESTRICT`},
+		{`DROP SCHEMA a RESTRICT`},
+
 		{`DROP TYPE a`},
 		{`DROP TYPE a, b, c`},
 		{`DROP TYPE db.sc.a, sc.a`},
@@ -1244,6 +1251,8 @@ func TestParse(t *testing.T) {
 		{`ALTER INDEX IF EXISTS a@b RENAME TO b`},
 		{`ALTER INDEX IF EXISTS a@primary RENAME TO like`},
 
+		{`ALTER SCHEMA s RENAME TO s2`},
+
 		{`ALTER TABLE a RENAME TO b`},
 		{`EXPLAIN ALTER TABLE a RENAME TO b`},
 		{`ALTER TABLE IF EXISTS a RENAME TO b`},
@@ -2814,7 +2823,6 @@ func TestUnimplementedSyntax(t *testing.T) {
 		{`DROP OPERATOR a`, 0, `drop operator`, ``},
 		{`DROP PUBLICATION a`, 0, `drop publication`, ``},
 		{`DROP RULE a`, 0, `drop rule`, ``},
-		{`DROP SCHEMA a`, 26443, `drop`, ``},
 		{`DROP SERVER a`, 0, `drop server`, ``},
 		{`DROP SUBSCRIPTION a`, 0, `drop subscription`, ``},
 		{`DROP TEXT SEARCH a`, 7821, `drop text`, ``},

pkg/sql/parser/sql.y

@@ -685,6 +685,7 @@ func (u *sqlSymUnion) executorType() tree.ScheduledJobExecutorType {
 %type <tree.Statement> alter_partition_stmt
 %type <tree.Statement> alter_role_stmt
 %type <tree.Statement> alter_type_stmt
+%type <tree.Statement> alter_schema_stmt
 
 // ALTER RANGE
 %type <tree.Statement> alter_zone_range_stmt
@@ -773,6 +774,7 @@ func (u *sqlSymUnion) executorType() tree.ScheduledJobExecutorType {
 %type <tree.Statement> drop_database_stmt
 %type <tree.Statement> drop_index_stmt
 %type <tree.Statement> drop_role_stmt
+%type <tree.Statement> drop_schema_stmt
 %type <tree.Statement> drop_table_stmt
 %type <tree.Statement> drop_type_stmt
 %type <tree.Statement> drop_view_stmt
@@ -907,6 +909,7 @@ func (u *sqlSymUnion) executorType() tree.ScheduledJobExecutorType {
 %type <*tree.UnresolvedObjectName> table_name standalone_index_name sequence_name type_name view_name db_object_name simple_db_object_name complex_db_object_name
 %type <[]*tree.UnresolvedObjectName> type_name_list
 %type <str> schema_name
+%type <[]string> schema_name_list
 %type <*tree.UnresolvedName> table_pattern complex_table_pattern
 %type <*tree.UnresolvedName> column_path prefixed_column_path column_path_with_star
 %type <tree.TableExpr> insert_target create_stats_target analyze_target
@@ -1234,6 +1237,7 @@ alter_ddl_stmt:
 | alter_database_stmt  // EXTEND WITH HELP: ALTER DATABASE
 | alter_range_stmt     // EXTEND WITH HELP: ALTER RANGE
 | alter_partition_stmt // EXTEND WITH HELP: ALTER PARTITION
+| alter_schema_stmt    // EXTEND WITH HELP: ALTER SCHEMA
 | alter_type_stmt      // EXTEND WITH HELP: ALTER TYPE
 
 // %Help: ALTER TABLE - change the definition of a table
@@ -2727,7 +2731,6 @@ drop_unsupported:
 | DROP OPERATOR error { return unimplemented(sqllex, "drop operator") }
 | DROP PUBLICATION error { return unimplemented(sqllex, "drop publication") }
 | DROP RULE error { return unimplemented(sqllex, "drop rule") }
-| DROP SCHEMA error { return unimplementedWithIssueDetail(sqllex, 26443, "drop") }
 | DROP SERVER error { return unimplemented(sqllex, "drop server") }
 | DROP SUBSCRIPTION error { return unimplemented(sqllex, "drop subscription") }
 | DROP TEXT error { return unimplementedWithIssueDetail(sqllex, 7821, "drop text") }
@@ -2949,6 +2952,7 @@ drop_ddl_stmt:
 | drop_table_stmt    // EXTEND WITH HELP: DROP TABLE
 | drop_view_stmt     // EXTEND WITH HELP: DROP VIEW
 | drop_sequence_stmt // EXTEND WITH HELP: DROP SEQUENCE
+| drop_schema_stmt   // EXTEND WITH HELP: DROP SCHEMA
 | drop_type_stmt     // EXTEND WITH HELP: DROP TYPE
 
 // %Help: DROP VIEW - remove a view
@@ -3066,7 +3070,6 @@ drop_type_stmt:
   }
 | DROP TYPE error // SHOW HELP: DROP TYPE
 
-
 type_name_list:
   type_name
   {
@@ -3077,6 +3080,37 @@ type_name_list:
     $$.val = append($1.unresolvedObjectNames(), $3.unresolvedObjectName())
   }
 
+// %Help: DROP SCHEMA - remove a schema
+// %Category: DDL
+// %Text: DROP SCHEMA [IF EXISTS] <schema_name> [, ...] [CASCADE | RESTRICT]
+drop_schema_stmt:
+  DROP SCHEMA schema_name_list opt_drop_behavior
+  {
+    $$.val = &tree.DropSchema{
+      Names: $3.strs(),
+      IfExists: false,
+      DropBehavior: $4.dropBehavior(),
+    }
+  }
+| DROP SCHEMA IF EXISTS schema_name_list opt_drop_behavior
+  {
+    $$.val = &tree.DropSchema{
+      Names: $5.strs(),
+      IfExists: true,
+      DropBehavior: $6.dropBehavior(),
+    }
+  }
+| DROP SCHEMA error // SHOW HELP: DROP SCHEMA
+
+schema_name_list:
+  schema_name
+  {
+    $$.val = []string{$1}
+  }
+| schema_name_list ',' schema_name
+  {
+    $$.val = append($1.strs(), $3)
+  }
 
 // %Help: DROP ROLE - remove a user
 // %Category: Priv
@@ -4929,6 +4963,29 @@ create_schema_stmt:
   }
 | CREATE SCHEMA error // SHOW HELP: CREATE SCHEMA
 
+// %Help: ALTER SCHEMA - alter an existing schema
+// %Category: DDL
+// %Text:
+//
+// Commands:
+//   ALTER SCHEMA ... RENAME TO <newschemaname>
+//   ALTER SCHEMA ... OWNER TO {<newowner> | CURRENT_USER | SESSION_USER }
+alter_schema_stmt:
+  ALTER SCHEMA schema_name RENAME TO schema_name
+  {
+    $$.val = &tree.AlterSchema{
+      Schema: $3,
+      Cmd: &tree.AlterSchemaRename{
+        NewName: $6,
+      },
+    }
+  }
+| ALTER SCHEMA schema_name OWNER TO role_spec
+  {
+    return unimplementedWithIssueDetail(sqllex, 50882, "ALTER SCHEMA OWNER TO")
+  }
+| ALTER SCHEMA error // SHOW HELP: ALTER SCHEMA
+
 // %Help: CREATE TABLE - create a new table
 // %Category: DDL
 // %Text: