xorm/session_exist.go
Lunny Xiao 5a5375a170 Improve statement (#1549)
Fix cache bug

Improve statement

Reviewed-on: xorm/xorm#1549
2020-02-27 00:34:16 +00:00

100 lines
2.6 KiB
Go

// Copyright 2017 The Xorm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package xorm
import (
"errors"
"fmt"
"reflect"
"xorm.io/builder"
"xorm.io/xorm/schemas"
)
// Exist returns true if the record exist otherwise return false
func (session *Session) Exist(bean ...interface{}) (bool, error) {
if session.isAutoClose {
defer session.Close()
}
if session.statement.lastError != nil {
return false, session.statement.lastError
}
var sqlStr string
var args []interface{}
var joinStr string
var err error
if session.statement.RawSQL == "" {
if len(bean) == 0 {
tableName := session.statement.TableName()
if len(tableName) <= 0 {
return false, ErrTableNotFound
}
tableName = session.statement.quote(tableName)
if len(session.statement.JoinStr) > 0 {
joinStr = session.statement.JoinStr
}
if session.statement.cond.IsValid() {
condSQL, condArgs, err := builder.ToSQL(session.statement.cond)
if err != nil {
return false, err
}
if session.engine.dialect.DBType() == schemas.MSSQL {
sqlStr = fmt.Sprintf("SELECT TOP 1 * FROM %s %s WHERE %s", tableName, joinStr, condSQL)
} else if session.engine.dialect.DBType() == schemas.ORACLE {
sqlStr = fmt.Sprintf("SELECT * FROM %s WHERE (%s) %s AND ROWNUM=1", tableName, joinStr, condSQL)
} else {
sqlStr = fmt.Sprintf("SELECT * FROM %s %s WHERE %s LIMIT 1", tableName, joinStr, condSQL)
}
args = condArgs
} else {
if session.engine.dialect.DBType() == schemas.MSSQL {
sqlStr = fmt.Sprintf("SELECT TOP 1 * FROM %s %s", tableName, joinStr)
} else if session.engine.dialect.DBType() == schemas.ORACLE {
sqlStr = fmt.Sprintf("SELECT * FROM %s %s WHERE ROWNUM=1", tableName, joinStr)
} else {
sqlStr = fmt.Sprintf("SELECT * FROM %s %s LIMIT 1", tableName, joinStr)
}
args = []interface{}{}
}
} else {
beanValue := reflect.ValueOf(bean[0])
if beanValue.Kind() != reflect.Ptr {
return false, errors.New("needs a pointer")
}
if beanValue.Elem().Kind() == reflect.Struct {
if err := session.statement.setRefBean(bean[0]); err != nil {
return false, err
}
}
if len(session.statement.TableName()) <= 0 {
return false, ErrTableNotFound
}
session.statement.Limit(1)
sqlStr, args, err = session.statement.genGetSQL(bean[0])
if err != nil {
return false, err
}
}
} else {
sqlStr = session.statement.RawSQL
args = session.statement.RawParams
}
rows, err := session.queryRows(sqlStr, args...)
if err != nil {
return false, err
}
defer rows.Close()
return rows.Next(), nil
}