ddl: support altering the other charset to utf8 or utf8mb4

ddl/column_test.go

@@ -915,7 +915,7 @@ func (s *testColumnSuite) TestModifyColumn(c *C) {
 		{"int", "int unsigned", errUnsupportedModifyColumn.GenWithStackByArgs("length 10 is less than origin 11")},
 		{"varchar(10)", "text", nil},
 		{"varbinary(10)", "blob", nil},
-		{"text", "blob", errUnsupportedModifyColumn.GenWithStackByArgs("charset binary not match origin utf8mb4")},
+		{"text", "blob", errUnsupportedModifyCharset.GenWithStackByArgs("charset from utf8mb4 to binary")},
 		{"varchar(10)", "varchar(8)", errUnsupportedModifyColumn.GenWithStackByArgs("length 8 is less than origin 10")},
 		{"varchar(10)", "varchar(11)", nil},
 		{"varchar(10) character set utf8 collate utf8_bin", "varchar(10) character set utf8", nil},

ddl/db_change_test.go

@@ -376,7 +376,7 @@ func (s *testStateChangeSuite) TestAppendEnum(c *C) {
 	c.Assert(err.Error(), Equals, "[ddl:203]unsupported modify column the number of enum column's elements is less than the original: 2")
 	failAlterTableSQL2 := "alter table t change c2 c2 int default 0"
 	_, err = s.se.Execute(context.Background(), failAlterTableSQL2)
-	c.Assert(err.Error(), Equals, "[ddl:203]unsupported modify column charset binary not match origin utf8mb4")
+	c.Assert(err.Error(), Equals, "[ddl:210]unsupported modify charset from utf8mb4 to binary")
 	alterTableSQL := "alter table t change c2 c2 enum('N','Y','A') DEFAULT 'A'"
 	_, err = s.se.Execute(context.Background(), alterTableSQL)
 	c.Assert(err, IsNil)

ddl/db_integration_test.go

@@ -152,6 +152,56 @@ func (s *testIntegrationSuite) TestEndIncluded(c *C) {
 	tk.MustExec("admin check table t")
 }
 
+func (s *testIntegrationSuite) TestChangingCharsetToUtf8(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+
+	tk.MustExec("USE test")
+	tk.MustExec("create table t(a char(10) charset latin1)")
+	tk.MustExec("alter table t modify column a char(10) charset latin1")
+	tk.MustExec("alter table t modify column a char(10) charset utf8")
+	tk.MustExec("alter table t modify column a char(10) charset utf8mb4")
+	rs, err := tk.Exec("alter table t modify column a char(10) charset utf8mb4 collate utf8bin")
+	if rs != nil {
+		rs.Close()
+	}
+	c.Assert(err, NotNil)
+	tk.MustExec("alter table t modify column a char(10) charset utf8mb4 collate utf8mb4_bin")
+	rs, err = tk.Exec("alter table t modify column a char(10) charset utf8 collate utf8_bin")
+	if rs != nil {
+		rs.Close()
+	}
+
+	c.Assert(err, NotNil)
+	tk.MustExec("alter table t modify column a char(10) charset utf8mb4 collate utf8mb4_general_ci")
+}
+
+func (s *testIntegrationSuite) TestChangingTableCharset(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+
+	tk.MustExec("USE test")
+	tk.MustExec("create table t(a char(10)) charset latin1 collate latin1_bin")
+	rs, err := tk.Exec("alter table t charset gbk")
+	if rs != nil {
+		rs.Close()
+	}
+	c.Assert(err.Error(), Equals, "Unknown charset gbk")
+	tk.MustExec("alter table t charset utf8")
+	tk.MustExec("alter table t charset utf8 collate utf8_bin")
+	rs, err = tk.Exec("alter table t charset utf8 collate latin1_bin")
+	if rs != nil {
+		rs.Close()
+	}
+	c.Assert(err, NotNil)
+	tk.MustExec("alter table t charset utf8mb4")
+	tk.MustExec("alter table t charset utf8mb4 collate utf8mb4_bin")
+
+	rs, err = tk.Exec("alter table t charset utf8 collate utf8_bin")
+	if rs != nil {
+		rs.Close()
+	}
+	c.Assert(err, NotNil)
+}
+
 func (s *testIntegrationSuite) TestCaseInsensitiveCharsetAndCollate(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 

ddl/db_test.go

@@ -27,6 +27,7 @@ import (
 	. "github.com/pingcap/check"
 	"github.com/pingcap/errors"
 	"github.com/pingcap/parser/ast"
+	"github.com/pingcap/parser/charset"
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/parser/mysql"
 	tmysql "github.com/pingcap/parser/mysql"
@@ -3831,6 +3832,98 @@ func testPartitionAddIndex(tk *testkit.TestKit, c *C) {
 	tk.MustExec("drop table partition_add_idx")
 }
 
+func (s *testDBSuite) TestAlterTableCharset(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("create database test_charset")
+	defer tk.MustExec("drop database test_charset")
+	tk.MustExec("use test_charset")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(a int) charset latin1")
+	ctx := tk.Se.(sessionctx.Context)
+	is := domain.GetDomain(ctx).InfoSchema()
+	t, err := is.TableByName(model.NewCIStr("test_charset"), model.NewCIStr("t"))
+	c.Assert(err, IsNil)
+	c.Assert(t.Meta().Charset, Equals, "latin1")
+	defCollate, err := charset.GetDefaultCollation("latin1")
+	c.Assert(err, IsNil)
+	c.Assert(t.Meta().Collate, Equals, defCollate)
+
+	tk.MustExec("alter table t charset utf8")
+	is = domain.GetDomain(ctx).InfoSchema()
+	t, err = is.TableByName(model.NewCIStr("test_charset"), model.NewCIStr("t"))
+	c.Assert(t.Meta().Charset, Equals, "utf8")
+	defCollate, err = charset.GetDefaultCollation("utf8")
+	c.Assert(err, IsNil)
+	c.Assert(t.Meta().Collate, Equals, defCollate)
+
+	tk.MustExec("alter table t charset utf8mb4 collate utf8mb4_general_ci")
+	is = domain.GetDomain(ctx).InfoSchema()
+	t, err = is.TableByName(model.NewCIStr("test_charset"), model.NewCIStr("t"))
+	c.Assert(t.Meta().Charset, Equals, "utf8mb4")
+	c.Assert(t.Meta().Collate, Equals, "utf8mb4_general_ci")
+
+	rs, err := tk.Exec("alter table t charset utf8")
+	if rs != nil {
+		rs.Close()
+	}
+
+	c.Assert(err.Error(), Equals, "[ddl:210]unsupported modify charset from utf8mb4 to utf8")
+}
+
+func (s *testDBSuite) TestAlterColumnCharset(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("create database test_charset")
+	defer tk.MustExec("drop database test_charset")
+	tk.MustExec("use test_charset")
+	tk.MustExec("drop table if exists t")
+	tk.MustExec("create table t(a char(10) charset latin1)")
+	ctx := tk.Se.(sessionctx.Context)
+	is := domain.GetDomain(ctx).InfoSchema()
+	t, err := is.TableByName(model.NewCIStr("test_charset"), model.NewCIStr("t"))
+	c.Assert(err, IsNil)
+	col := model.FindColumnInfo(t.Meta().Columns, "a")
+	c.Assert(col, NotNil)
+	c.Assert(col.Charset, Equals, "latin1")
+	defCollate, err := charset.GetDefaultCollation("latin1")
+	c.Assert(err, IsNil)
+	c.Assert(col.Collate, Equals, defCollate)
+
+	tk.MustExec("alter table t modify column a char(10) charset utf8")
+	is = domain.GetDomain(ctx).InfoSchema()
+	t, err = is.TableByName(model.NewCIStr("test_charset"), model.NewCIStr("t"))
+	c.Assert(err, IsNil)
+	col = model.FindColumnInfo(t.Meta().Columns, "a")
+	c.Assert(col, NotNil)
+	c.Assert(col.Charset, Equals, "utf8")
+	defCollate, err = charset.GetDefaultCollation("utf8")
+	c.Assert(err, IsNil)
+	c.Assert(col.Collate, Equals, defCollate)
+
+	tk.MustExec("alter table t modify column a char(10) charset utf8 collate utf8_general_ci")
+	is = domain.GetDomain(ctx).InfoSchema()
+	t, err = is.TableByName(model.NewCIStr("test_charset"), model.NewCIStr("t"))
+	c.Assert(err, IsNil)
+	col = model.FindColumnInfo(t.Meta().Columns, "a")
+	c.Assert(col, NotNil)
+	c.Assert(col.Charset, Equals, "utf8")
+	c.Assert(col.Collate, Equals, "utf8_general_ci")
+
+	tk.MustExec("alter table t modify column a char(10) charset utf8mb4 collate utf8mb4_general_ci")
+	is = domain.GetDomain(ctx).InfoSchema()
+	t, err = is.TableByName(model.NewCIStr("test_charset"), model.NewCIStr("t"))
+	c.Assert(err, IsNil)
+	col = model.FindColumnInfo(t.Meta().Columns, "a")
+	c.Assert(col, NotNil)
+	c.Assert(col.Charset, Equals, "utf8mb4")
+	c.Assert(col.Collate, Equals, "utf8mb4_general_ci")
+
+	rs, err := tk.Exec("alter table t modify column a char(10) charset utf8")
+	if rs != nil {
+		rs.Close()
+	}
+	c.Assert(err.Error(), Equals, "[ddl:210]unsupported modify charset from utf8mb4 to utf8")
+}
+
 func (s *testDBSuite) TestDropSchemaWithPartitionTable(c *C) {
 	s.tk = testkit.NewTestKit(c, s.store)
 	s.tk.MustExec("drop database if exists test_db_with_partition")

ddl/ddl.go

@@ -84,10 +84,11 @@ var (
 	errInvalidStoreVer       = terror.ClassDDL.New(codeInvalidStoreVer, "invalid storage current version")
 
 	// We don't support dropping column with index covered now.
-	errCantDropColWithIndex    = terror.ClassDDL.New(codeCantDropColWithIndex, "can't drop column with index")
-	errUnsupportedAddColumn    = terror.ClassDDL.New(codeUnsupportedAddColumn, "unsupported add column")
-	errUnsupportedModifyColumn = terror.ClassDDL.New(codeUnsupportedModifyColumn, "unsupported modify column %s")
-	errUnsupportedPKHandle     = terror.ClassDDL.New(codeUnsupportedDropPKHandle,
+	errCantDropColWithIndex     = terror.ClassDDL.New(codeCantDropColWithIndex, "can't drop column with index")
+	errUnsupportedAddColumn     = terror.ClassDDL.New(codeUnsupportedAddColumn, "unsupported add column")
+	errUnsupportedModifyColumn  = terror.ClassDDL.New(codeUnsupportedModifyColumn, "unsupported modify column %s")
+	errUnsupportedModifyCharset = terror.ClassDDL.New(codeUnsupportedModifyCharset, "unsupported modify %s")
+	errUnsupportedPKHandle      = terror.ClassDDL.New(codeUnsupportedDropPKHandle,
 		"unsupported drop integer primary key")
 	errUnsupportedCharset = terror.ClassDDL.New(codeUnsupportedCharset, "unsupported charset %s collate %s")
 
@@ -587,6 +588,7 @@ const (
 	codeUnsupportedShardRowIDBits    = 207
 	codeUnsupportedAddPartition      = 208
 	codeUnsupportedCoalescePartition = 209
+	codeUnsupportedModifyCharset     = 210
 
 	codeFileNotFound                           = 1017
 	codeErrorOnRename                          = 1025