fix(memory): Use text as the underlying type of string (coze-dev#129)

Author: liuyunchao-1998

backend/domain/memory/database/internal/convertor/types.go

@@ -33,7 +33,7 @@ const (
 func SwitchToDataType(itemType table.FieldItemType) entity.DataType {
 	switch itemType {
 	case table.FieldItemType_Text:
-		return entity.TypeVarchar
+		return entity.TypeText
 	case table.FieldItemType_Number:
 		return entity.TypeBigInt
 	case table.FieldItemType_Date:

backend/infra/impl/rdb/mysql.go

@@ -64,6 +64,8 @@ func (m *mysqlService) CreateTable(ctx context.Context, req *rdb.CreateTableRequ
 		if col.DefaultValue != nil {
 			if col.DataType == entity2.TypeTimestamp {
 				colDef += fmt.Sprintf(" DEFAULT %s", *col.DefaultValue)
+			} else if col.DataType == entity2.TypeText {
+				// do nothing
 			} else {
 				colDef += fmt.Sprintf(" DEFAULT '%s'", *col.DefaultValue)
 			}