使用带有OUT参数的VB6调用MySQL存储过程

本文介绍了使用带有OUT参数的VB6调用MySQL存储过程的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我已经在MySQL(服务器5.5)中编写了此过程

I have written this procedure in MySQL (Server 5.5)

DELIMITER $$ DROP PROCEDURE IF EXISTS `InsertList` $$ CREATE DEFINER=`root`@`localhost` PROCEDURE `InsertList`(IN fName VARCHAR(20), IN fType VARCHAR(3), IN fFood varchar(20), Out fResult int) BEGIN insert into tblguest (firstname, confirm, food) values (fName, fType, fFood); select count(id) from tblguest into fResult; END $$ DELIMITER ;

当我从MySQL查询浏览器调用此过程时，它会按预期返回

When I call this procedure from MySQL Query Browser it returns as expected

Call InsertList ('V1', 'No', 'F1', @result); Select @result;

->它成功返回表中ID的数量

--> It successfully returns the count of the ids in the table

我在VB6中编写了以下代码

I wrote the following code in VB6

Dim res As Integer On Error GoTo chkErr Set cmd = New ADODB.Command cmd.ActiveConnection = cn cmd.CommandType = adCmdStoredProc cmd.CommandText = "InsertList" cmd.Parameters.Append cmd.CreateParameter("fName", adVarChar, adParamInput, 20, Text3.Text) cmd.Parameters.Append cmd.CreateParameter("fType", adVarChar, adParamInput, 3, Text2.Text) cmd.Parameters.Append cmd.CreateParameter("fFood", adVarChar, adParamInput, 20, Text1.Text) cmd.Parameters.Append cmd.CreateParameter("fResult", adInteger,adParamOutput) cmd.Execute res = cmd("fResult") MsgBox res Exit Sub chkErr: Select Case Err.Number Case Else Text4.Text = Err.Number & " - " & Err.Description End Select

但是当它尝试运行语句cmd.execute时，会引发以下错误:

But the moment it tries to run the statement cmd.execute it throws the following error :

-2147467259-[MySQL] [ODBC 5.1驱动程序] [mysqld-5.5.34]例程dbtest.InsertList的OUT或INOUT参数4不是变量或NEW 触发前的伪变量

-2147467259 - [MySQL][ODBC 5.1 Driver][mysqld-5.5.34]OUT or INOUT argument 4 for routine dbtest.InsertList is not a variable or NEW pseudo-variable in BEFORE trigger

我已经看到了适用于SQL的代码，那么MySQL本身在使用带有OUT参数的存储过程时是否会遇到问题?

I have seen codes working for SQL, so is it that MySQL itself has an issue using Stored Procedure with an OUT Parameter?

推荐答案

这似乎是来自MySQL ODBC和C/API的未解决的错误

It seems a unsolved bug from MySQL ODBC and C/API

一种解决方案是使用带有准备好的变量的SQL命令执行该操作:

One solution is to execute that using a SQL command with prepared variables:

Dim rs As ADODB.Recordset Set cmd = New ADODB.Command cmd.ActiveConnection = cn cmd.CommandType = adCmdText cmd.CommandText = "call InsertList(?,?,?,@fResult)" cmd.Parameters.Append cmd.CreateParameter("fName", adVarChar, adParamInput, 20, Text3.Text) cmd.Parameters.Append cmd.CreateParameter("fType", adVarChar, adParamInput, 3, Text2.Text) cmd.Parameters.Append cmd.CreateParameter("fFood", adVarChar, adParamInput, 20, Text1.Text) cmd.Execute 'And after that, using the same connection, get the value of '@fResult from a single query: Set rs = cn.Execute("select @fResult as fResult") MsgBox rs!fResult

您将获得期望值.