Output parameter of MySQL stored procedures via ADODB in MS Access (VBA) correct on one computer and random on another

问题

I have tried (nearly) everything to isolate the problem, but I am lost.

I have an MS Access application that uses ADODB to interface to a local MySQL database. I copied it to a new computer, but now the output parameters of the stored procedures contain a random value each time (if done via ADODB). When executed in MySQL WorkBench, the output parameters are correct.

Here are the specs of the 2 computers:

old: Windows 7 Pro, Office 2010 ProPlus, MySQL ODBC 5.3.4, MySQL server 5.6.22 (all are 64-bit; 32-bit ODBC is also installed);
new: Windows 10 Pro, Office 2016 ProPlus, MySQL ODBC 5.3.6, MySQL server 5.7.16 (all are 64-bit, except MS Office; 32-bit ODBC is also installed).

To isolate the problem, I used the following simple stored procedure:

CREATE PROCEDURE `testit`(
    OUT iTest INT(11))
BEGIN
    SET iTest = 123;
END

And a test MS Access database containing only the following VBA code (and a reference to the Microsoft ActiveX Data Objects 6.1 library):

Public Function dbTestIt() As Long

Dim dbConn As ADODB.Connection
Dim dbCmd As ADODB.Command

    'Open new connection
    Set dbConn = New ADODB.Connection
    dbConn.ConnectionString = "Driver={MySQL ODBC 5.3 Ansi Driver};option=3;database=xxx;user=root;password=yyy;"
    dbConn.Open

    'Execute new command
    Set dbCmd = New ADODB.Command
    With dbCmd
        Set .ActiveConnection = dbConn
        .CommandTimeout = 0
        .CommandType = adCmdStoredProc
        .CommandText = "testit"
        .Parameters.Append dbCmd.CreateParameter("iTest", adInteger, adParamOutput)
        .Execute
        dbTestIt = dbCmd.Parameters.Item(0).Value
    End With

    'Close Connection
    dbConn.Close

End Function

Here are the test results:

On the old computer, dbTestIt() always returns 123;
On the new computer, dbTestIt() returns random values (e.g. 51, 1936020585, 1);
And if I connect from the new computer to the MySQL server on the old computer (using server=192.168.1.x in the connection string), it always returns 123 as well;
This tells me the problem is (only) in the MySQL server on the new computer (right?);
However, if I then connect from the old computer to the MySQL server on the new computer, it also always returns 123!

So the problem seems to be in the combination of the components on the new computer, but which and why? And how to test it?

Anybody any bright ideas?

回答1:

To further locate the cause of the problem, I downgraded the MySQL ODBC driver 5.3.6 on the new computer to version 5.3.4 (which is on the old computer) and now it works! To confirm that this is indeed the cause, I upgraded to version 5.3.6 again and it failed again.

So it looks like MySQL ODBC driver 5.3.6 (released 8 months ago!) has problems handling output parameters from a (local) MySQL Server 5.7.16, maybe only in combination with ADODB and Windows 10.

So for the moment I will use the 5.3.4 version and report a bug to MySQL.

回答2:

MySQL server version 5.7 has compatibility issues with latest ODBC connectors. Downgrading the server to version 5.6 fixed the issue.

来源：https://stackoverflow.com/questions/40531411/output-parameter-of-mysql-stored-procedures-via-adodb-in-ms-access-vba-correct

标签

mysql

ms-access

stored-procedures

adodb

output-parameter