executor, infoschema: Add foreign key constraint to infoschema.table_constraints

executor/infoschema_reader.go

@@ -1643,6 +1643,18 @@ func (e *memtableRetriever) setDataFromTableConstraints(ctx sessionctx.Context,
 				)
 				rows = append(rows, record)
 			}
+			//  TiDB includes foreign key information for compatibility but foreign keys are not yet enforced.
+			for _, fk := range tbl.ForeignKeys {
+				record := types.MakeDatums(
+					infoschema.CatalogVal,     // CONSTRAINT_CATALOG
+					schema.Name.O,             // CONSTRAINT_SCHEMA
+					fk.Name.O,                 // CONSTRAINT_NAME
+					schema.Name.O,             // TABLE_SCHEMA
+					tbl.Name.O,                // TABLE_NAME
+					infoschema.ForeignKeyType, // CONSTRAINT_TYPE
+				)
+				rows = append(rows, record)
+			}
 		}
 	}
 	e.rows = rows

infoschema/tables.go

@@ -1496,6 +1496,8 @@ const (
 	PrimaryConstraint = "PRIMARY"
 	// UniqueKeyType is the string constant of UNIQUE.
 	UniqueKeyType = "UNIQUE"
+	// ForeignKeyType is the string constant of Foreign Key.
+	ForeignKeyType = "FOREIGN KEY"
 )
 
 // ServerInfo represents the basic server information of single cluster component

infoschema/tables_test.go

@@ -698,7 +698,7 @@ func TestFormatVersion(t *testing.T) {
 	}
 }
 
-// Test statements_summary.
+// TestStmtSummaryTable Test statements_summary.
 func TestStmtSummaryTable(t *testing.T) {
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -1005,7 +1005,7 @@ func TestIssue18845(t *testing.T) {
 	tk.MustQuery(`select count(*) from information_schema.columns;`)
 }
 
-// Test statements_summary_history.
+// TestStmtSummaryInternalQuery Test statements_summary_history.
 func TestStmtSummaryInternalQuery(t *testing.T) {
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -1064,7 +1064,7 @@ func TestStmtSummaryInternalQuery(t *testing.T) {
 	require.Contains(t, rows[0][0].(string), "Projection")
 }
 
-// Test error count and warning count.
+// TestStmtSummaryErrorCount Test error count and warning count.
 func TestStmtSummaryErrorCount(t *testing.T) {
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -1135,7 +1135,7 @@ func TestStmtSummarySensitiveQuery(t *testing.T) {
 		))
 }
 
-// test stmtSummaryEvictedCount
+// TestSimpleStmtSummaryEvictedCount test stmtSummaryEvictedCount
 func TestSimpleStmtSummaryEvictedCount(t *testing.T) {
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()
@@ -1498,3 +1498,16 @@ func TestReferentialConstraints(t *testing.T) {
 
 	tk.MustQuery(`SELECT * FROM information_schema.referential_constraints WHERE table_name='t2'`).Check(testkit.Rows("def referconstraints fk_to_t1 def referconstraints PRIMARY NONE NO ACTION NO ACTION t2 t1"))
 }
+
+// TestTableConstraintsContainForeignKeys TiDB Issue: https://github.com/pingcap/tidb/issues/28918
+func TestTableConstraintsContainForeignKeys(t *testing.T) {
+	store, clean := testkit.CreateMockStore(t)
+	defer clean()
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("CREATE DATABASE tableconstraints")
+	tk.MustExec("use tableconstraints")
+	tk.MustExec("CREATE TABLE `t1` (`id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(25) DEFAULT NULL, PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;")
+	tk.MustExec("CREATE TABLE `t2` (`id` int(11) NOT NULL AUTO_INCREMENT, `t1_id` int(11) DEFAULT NULL,	PRIMARY KEY (`id`) /*T![clustered_index] CLUSTERED */,	CONSTRAINT `fk_t2_t1` FOREIGN KEY (`t1_id`) REFERENCES `t1` (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;")
+	tk.MustQuery("SELECT *  FROM INFORMATION_SCHEMA.table_constraints WHERE constraint_schema = 'tableconstraints' AND table_name = 't2'").Sort().Check(testkit.Rows("def tableconstraints PRIMARY tableconstraints t2 PRIMARY KEY", "def tableconstraints fk_t2_t1 tableconstraints t2 FOREIGN KEY"))
+	tk.MustQuery("SELECT *  FROM INFORMATION_SCHEMA.table_constraints WHERE constraint_schema = 'tableconstraints' AND table_name = 't1'").Sort().Check(testkit.Rows("def tableconstraints PRIMARY tableconstraints t1 PRIMARY KEY"))
+}