In SQLite3, Sync doesn't support Modify Column：Error: near MODIFY: syntax error (#2267)

rebase

Co-authored-by: brookechen <brookechen@noreply.gitea.io>
Co-authored-by: brookechen <brookechen@tencent.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-on: https://gitea.com/xorm/xorm/pulls/2267
Co-authored-by: brookechen <brookechen@noreply.gitea.com>
Co-committed-by: brookechen <brookechen@noreply.gitea.com>

dialects/mysql.go

@@ -397,6 +397,9 @@ func (db *mysql) AddColumnSQL(tableName string, col *schemas.Column) string {
 // ModifyColumnSQL returns a SQL to modify SQL
 func (db *mysql) ModifyColumnSQL(tableName string, col *schemas.Column) string {
 	s, _ := ColumnString(db.dialect, col, false, true)
+	if col.Comment != "" {
+		s += fmt.Sprintf(" COMMENT '%s'", col.Comment)
+	}
 	return fmt.Sprintf("ALTER TABLE %s MODIFY COLUMN %s", db.quoter.Quote(tableName), s)
 }
 

integrations/engine_test.go

@@ -289,6 +289,48 @@ func TestGetColumnsComment(t *testing.T) {
 	assert.Zero(t, noComment)
 }
 
+type TestCommentUpdate struct {
+	HasComment int `xorm:"bigint comment('this is a comment before update')"`
+}
+
+func (m *TestCommentUpdate) TableName() string {
+	return "test_comment_struct"
+}
+
+type TestCommentUpdate2 struct {
+	HasComment int `xorm:"bigint comment('this is a comment after update')"`
+}
+
+func (m *TestCommentUpdate2) TableName() string {
+	return "test_comment_struct"
+}
+
+func TestColumnCommentUpdate(t *testing.T) {
+	comment := "this is a comment after update"
+	assertSync(t, new(TestCommentUpdate))
+	assert.NoError(t, testEngine.Sync2(new(TestCommentUpdate2))) // modify table column comment
+
+	switch testEngine.Dialect().URI().DBType {
+	case schemas.POSTGRES, schemas.MYSQL: // only postgres / mysql dialect implement the feature of modify comment in postgres.ModifyColumnSQL
+	default:
+		t.Skip()
+		return
+	}
+	tables, err := testEngine.DBMetas()
+	assert.NoError(t, err)
+	tableName := "test_comment_struct"
+	var hasComment string
+	for _, table := range tables {
+		if table.Name == tableName {
+			col := table.GetColumn(testEngine.GetColumnMapper().Obj2Table("HasComment"))
+			assert.NotNil(t, col)
+			hasComment = col.Comment
+			break
+		}
+	}
+	assert.Equal(t, comment, hasComment)
+}
+
 func TestGetColumnsLength(t *testing.T) {
 	var max_length int64
 	switch testEngine.Dialect().URI().DBType {

sync.go

@@ -181,8 +181,11 @@ func (session *Session) SyncWithOptions(opts SyncOptions, beans ...interface{})
 					}
 				}
 			} else if col.Comment != oriCol.Comment {
+				if engine.dialect.URI().DBType == schemas.POSTGRES ||
+					engine.dialect.URI().DBType == schemas.MYSQL {
 					_, err = session.exec(engine.dialect.ModifyColumnSQL(tbNameWithSchema, col))
 				}
+			}
 
 			if col.Default != oriCol.Default {
 				switch {