使用带有OUT参数的VB6调用MySQL存储过程 [英] Calling MySQL Stored Procedure using VB6 with OUT Parameter

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.

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