*: enable foreign_key_checks variable by default

ddl/cancel_test.go

@@ -150,7 +150,7 @@ var allTestCase = []testCancelJob{
 	{"alter table t modify column c11 char(10)", false, model.StatePublic, false, true, nil},
 	// Add foreign key.
 	{"alter table t add constraint fk foreign key a(c1) references t_ref(c1)", true, model.StateNone, true, false, []string{"create table t_ref (c1 int key, c2 int, c3 int, c11 tinyint);"}},
-	{"alter table t add constraint fk foreign key a(c1) references t_ref(c1)", false, model.StatePublic, false, true, nil},
+	{"alter table t add constraint fk foreign key a(c1) references t_ref(c1)", false, model.StatePublic, false, true, []string{"insert into t_ref (c1) select c1 from t;"}},
 	// Drop foreign key.
 	{"alter table t drop foreign key fk", true, model.StatePublic, true, false, nil},
 	{"alter table t drop foreign key fk", false, model.StateNone, false, true, nil},

ddl/column_type_change_test.go

@@ -1812,8 +1812,7 @@ func TestChangingAttributeOfColumnWithFK(t *testing.T) {
 	tk.MustExec("use test")
 
 	prepare := func() {
-		tk.MustExec("drop table if exists users")
-		tk.MustExec("drop table if exists orders")
+		tk.MustExec("drop table if exists users, orders")
 		tk.MustExec("CREATE TABLE users (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, doc JSON);")
 		tk.MustExec("CREATE TABLE orders (id INT NOT NULL PRIMARY KEY AUTO_INCREMENT, user_id INT NOT NULL, doc JSON, FOREIGN KEY fk_user_id (user_id) REFERENCES users(id));")
 	}

ddl/db_foreign_key_test.go

@@ -26,8 +26,7 @@ func TestDuplicateForeignKey(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)
 	tk.MustExec("use test")
-	tk.MustExec("drop table if exists t")
-	tk.MustExec("drop table if exists t1")
+	tk.MustExec("drop table if exists t, t1")
 	// Foreign table.
 	tk.MustExec("create table t(id int key)")
 	// Create target table with duplicate fk.
@@ -38,8 +37,7 @@ func TestDuplicateForeignKey(t *testing.T) {
 	// Alter target table with duplicate fk.
 	tk.MustGetErrCode("alter table t1 add CONSTRAINT `fk_aaa` FOREIGN KEY (`id_fk`) REFERENCES `t` (`id`)", mysql.ErrFkDupName)
 	tk.MustGetErrCode("alter table t1 add CONSTRAINT `fk_aAa` FOREIGN KEY (`id_fk`) REFERENCES `t` (`id`)", mysql.ErrFkDupName)
-	tk.MustExec("drop table if exists t")
-	tk.MustExec("drop table if exists t1")
+	tk.MustExec("drop table if exists t, t1")
 }
 
 func TestTemporaryTableForeignKey(t *testing.T) {

ddl/db_integration_test.go

@@ -2378,6 +2378,7 @@ func TestParserIssue284(t *testing.T) {
 
 	tk := testkit.NewTestKit(t, store)
 	tk.MustExec("use test")
+	tk.MustExec("set @@foreign_key_checks=0")
 	tk.MustExec("create table test.t_parser_issue_284(c1 int not null primary key)")
 	_, err := tk.Exec("create table test.t_parser_issue_284_2(id int not null primary key, c1 int not null, constraint foreign key (c1) references t_parser_issue_284(c1))")
 	require.NoError(t, err)

ddl/serial_test.go

@@ -112,6 +112,7 @@ func TestCreateTableWithLike(t *testing.T) {
 	tk.MustExec("use ctwl_db")
 	tk.MustExec("create table tt(id int primary key)")
 	tk.MustExec("create table t (c1 int not null auto_increment, c2 int, constraint cc foreign key (c2) references tt(id), primary key(c1)) auto_increment = 10")
+	tk.MustExec("set @@foreign_key_checks=0")
 	tk.MustExec("insert into t set c2=1")
 	tk.MustExec("create table t1 like ctwl_db.t")
 	tk.MustExec("insert into t1 set c2=11")

executor/explain_test.go

@@ -247,6 +247,7 @@ func TestExplainAnalyzeExecutionInfo(t *testing.T) {
 	checkExecutionInfo(t, tk, "explain analyze select * from t use index(k)")
 	checkExecutionInfo(t, tk, "explain analyze with recursive cte(a) as (select 1 union select a + 1 from cte where a < 1000) select * from cte;")
 
+	tk.MustExec("set @@foreign_key_checks=0")
 	tk.MustExec("CREATE TABLE IF NOT EXISTS nation  ( N_NATIONKEY  BIGINT NOT NULL,N_NAME       CHAR(25) NOT NULL,N_REGIONKEY  BIGINT NOT NULL,N_COMMENT    VARCHAR(152),PRIMARY KEY (N_NATIONKEY));")
 	tk.MustExec("CREATE TABLE IF NOT EXISTS part  ( P_PARTKEY     BIGINT NOT NULL,P_NAME        VARCHAR(55) NOT NULL,P_MFGR        CHAR(25) NOT NULL,P_BRAND       CHAR(10) NOT NULL,P_TYPE        VARCHAR(25) NOT NULL,P_SIZE        BIGINT NOT NULL,P_CONTAINER   CHAR(10) NOT NULL,P_RETAILPRICE DECIMAL(15,2) NOT NULL,P_COMMENT     VARCHAR(23) NOT NULL,PRIMARY KEY (P_PARTKEY));")
 	tk.MustExec("CREATE TABLE IF NOT EXISTS supplier  ( S_SUPPKEY     BIGINT NOT NULL,S_NAME        CHAR(25) NOT NULL,S_ADDRESS     VARCHAR(40) NOT NULL,S_NATIONKEY   BIGINT NOT NULL,S_PHONE       CHAR(15) NOT NULL,S_ACCTBAL     DECIMAL(15,2) NOT NULL,S_COMMENT     VARCHAR(101) NOT NULL,PRIMARY KEY (S_SUPPKEY),CONSTRAINT FOREIGN KEY SUPPLIER_FK1 (S_NATIONKEY) references nation(N_NATIONKEY));")

executor/issuetest/executor_issue_test.go

@@ -532,6 +532,7 @@ func TestFix31537(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)
 	tk.MustExec("use test")
+	tk.MustExec("set @@foreign_key_checks=0")
 	tk.MustExec(`CREATE TABLE trade (
   t_id bigint(16) NOT NULL AUTO_INCREMENT,
   t_dts datetime NOT NULL,

executor/set_test.go

@@ -799,15 +799,15 @@ func TestSetVar(t *testing.T) {
 
 	// test variable 'foreign_key_checks'
 	// global scope
-	tk.MustQuery("select @@global.foreign_key_checks").Check(testkit.Rows("0")) // default value
-	tk.MustExec("set global foreign_key_checks = 1")
-	tk.MustQuery("select @@global.foreign_key_checks").Check(testkit.Rows("1"))
+	tk.MustQuery("select @@global.foreign_key_checks").Check(testkit.Rows("1")) // default value
+	tk.MustExec("set global foreign_key_checks = 0")
+	tk.MustQuery("select @@global.foreign_key_checks").Check(testkit.Rows("0"))
 	// session scope
-	tk.MustQuery("select @@session.foreign_key_checks").Check(testkit.Rows("0")) // default value
-	tk.MustExec("set session foreign_key_checks = 1")
-	tk.MustQuery("select @@session.foreign_key_checks").Check(testkit.Rows("1"))
+	tk.MustQuery("select @@session.foreign_key_checks").Check(testkit.Rows("1")) // default value
+	tk.MustExec("set session foreign_key_checks = 0")
+	tk.MustQuery("select @@session.foreign_key_checks").Check(testkit.Rows("0"))
 
-	// test variable 'foreign_key_checks'
+	// test variable 'tidb_enable_foreign_key'
 	// global scope
 	tk.MustQuery("select @@global.tidb_enable_foreign_key").Check(testkit.Rows("1")) // default value
 	tk.MustExec("set global tidb_enable_foreign_key = 0")

executor/showtest/show_test.go

@@ -318,9 +318,10 @@ func TestShowCreateTable(t *testing.T) {
 			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin",
 	))
 
-	// TiDB defaults (and only supports) foreign_key_checks=0
+	// set @@foreign_key_checks=0,
 	// This means that the child table can be created before the parent table.
 	// This behavior is required for mysqldump restores.
+	tk.MustExec("set @@foreign_key_checks=0")
 	tk.MustExec(`DROP TABLE IF EXISTS parent, child`)
 	tk.MustExec(`CREATE TABLE child (id INT NOT NULL PRIMARY KEY auto_increment, parent_id INT NOT NULL, INDEX par_ind (parent_id), CONSTRAINT child_ibfk_1 FOREIGN KEY (parent_id) REFERENCES parent(id))`)
 	tk.MustExec(`CREATE TABLE parent ( id INT NOT NULL PRIMARY KEY auto_increment )`)

planner/core/point_get_plan.go

@@ -1687,10 +1687,12 @@ func buildPointDeletePlan(ctx sessionctx.Context, pointPlan PhysicalPlan, dbName
 	var err error
 	is := sessiontxn.GetTxnManager(ctx).GetTxnInfoSchema()
 	t, _ := is.TableByID(tbl.ID)
-	tblID2Table := map[int64]table.Table{tbl.ID: t}
-	err = delPlan.buildOnDeleteFKTriggers(ctx, is, tblID2Table)
-	if err != nil {
-		return nil
+	if t != nil {
+		tblID2Table := map[int64]table.Table{tbl.ID: t}
+		err = delPlan.buildOnDeleteFKTriggers(ctx, is, tblID2Table)
+		if err != nil {
+			return nil
+		}
 	}
 	return delPlan
 }

session/session_test/session_test.go

@@ -2961,6 +2961,7 @@ func TestIgnoreForeignKey(t *testing.T) {
 
 	tk := testkit.NewTestKit(t, store)
 	tk.MustExec("use test")
+	tk.MustExec("set @@foreign_key_checks=0")
 	sqlText := `CREATE TABLE address (
 		id bigint(20) NOT NULL AUTO_INCREMENT,
 		user_id bigint(20) NOT NULL,

sessionctx/variable/tidb_vars.go

@@ -1110,7 +1110,7 @@ const (
 	DefTiDBAutoBuildStatsConcurrency             = 1
 	DefTiDBSysProcScanConcurrency                = 1
 	DefTiDBRcWriteCheckTs                        = false
-	DefTiDBForeignKeyChecks                      = false
+	DefTiDBForeignKeyChecks                      = true
 	DefTiDBAnalyzePartitionConcurrency           = 1
 	DefTiDBOptRangeMaxSize                       = 64 * int64(size.MB) // 64 MB
 	DefTiDBCostModelVer                          = 2