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Stored Procedure with Prepared Statements to build SQL
Posted by: Daniel Hofer
Date: February 27, 2012 02:17PM

This is a stored Procedure workaround to the limitation that an ADODB recordset cannot be assigned as an ACCDB Access report recordsource.

Private Sub Report_Open(Cancel As Integer)
Dim cmdStr As String
Dim cmd As ADODB.Command
Dim rs As ADODB.Recordset
Dim strConn, strServer As String

Set cmd = New ADODB.Command

strServer = TempVars![MySQLServer]
strConn = "ODBC;MySQL ODBC 5.1 Driver;UID=hdbmysqluser;PORT=3306;DATABASE=hdb;PASSWORD=x; SERVER=" & strServer & ";FILEDSN=C:\AccessHdb\HDB\HDB.dsn;"

With cmd
.ActiveConnection = strConn
.CommandText = "CALL sp_tempviewinvoicesummary('2012-01-01', '2012-2-27', '%');"
.CommandType = adCmdText
End With

Set rs = cmd.Execute

' the following shows the recordset has data
Do While Not rs.EOF
Debug.Print rs!COMPANY
rs.MoveNext
Loop

' the following line will not work
Me.Recordset = rs

Set cmd = Nothing
Set rs = Nothing

End Sub
-----------------------------------------------------------------------------------

Work Around:
The following stored procedure is used to fill a MySQL table with records
for the Access report to use as a recordsource.

DELIMITER $$

CREATE PROCEDURE `sp_tempviewinvoicesummary`(invdatestart TEXT, invdateend TEXT, sproj TEXT)
BEGIN

DECLARE spj TEXT;

-- Note: '\'' below is 'single quote'
-- if sproj = '%', want to include records with sproj = null
IF sproj = '%' then
SET spj = CONCAT(' AND (v.sproj LIKE ', '\'', sproj, '\'', ' OR v.sproj IS NULL) ');
ELSEIF INSTR(UPPER(sproj), 'NOT NULL') > 0 then
SET spj = ' AND v.sproj IS NOT NULL';
ELSEIF INSTR(UPPER(sproj), 'NULL') > 0 then
SET spj = ' AND v.sproj IS NULL';
ELSE
SET spj = CONCAT(' AND v.sproj LIKE ', '\'', sproj, '\'');
end if;

SET @str = CONCAT('CREATE TABLE tempviewinvoicesummary
SELECT * FROM viewinvoicesummary AS v
WHERE v.invdate >= \'',invdatestart, '\'',
' AND v.invdate <= \'', invdateend, '\'', spj,
' ORDER BY v.invdate DESC, v.invoiceno DESC;');

-- SELECT @str; used while testing, to check the sql string that was built

BEGIN
DECLARE CONTINUE HANDLER FOR SQLSTATE '42S02' BEGIN END;
DROP TABLE tempviewinvoicesummary;
END;

PREPARE stmt FROM @str;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

END

Call sp_tempviewinvoicesummary from Access:

Private Sub Report_Open(Cancel As Integer)
Dim cmdStr As String
Dim cmd As ADODB.Command
Dim strConn, strServer As String

Set cmd = New ADODB.Command

strServer = TempVars![MySQLServer]
strConn = "ODBC;MySQL ODBC 5.1 Driver;UID=hdbmysqluser;PORT=3306;DATABASE=hdb;PASSWORD=x; SERVER=" & strServer & ";FILEDSN=C:\AccessHdb\HDB\HDB.dsn;"

'cmdStr is built in a criteria form [actual report has many criteria fields] see samples below
cmdStr = TempVars![rptCriteriaCommand]

With cmd
.ActiveConnection = strConn
.CommandText = cmdStr
.CommandType = adCmdText
.Execute
End With

Set cmd = Nothing

End Sub

Four example calls, sproj is a LONG but can be null:

CALL sp_tempviewinvoicesummary('2012-01-01', '2012-2-27', '%'); show sproj non-null and null records
CALL sp_tempviewinvoicesummary('2012-01-01', '2012-2-27', '3112162'); show sproj matching records
CALL sp_tempviewinvoicesummary('2012-01-01', '2012-2-27', 'NULL'); show records with sproj IS NULL
CALL sp_tempviewinvoicesummary('2012-01-01', '2012-2-27', 'NOT NULL'); show records with sproj IS NOT NULL

The table needs to be dropped when the report is closed. Only 1 person can run this report at a time
unless the stored procedure created table name is made unique for each Call.

It's easier and cleaner to just use a pass through query, but I'm trying to build functionality into MySQL
so that it can be used in another front end.

I entertain any comments about improvements.

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Stored Procedure with Prepared Statements to build SQL
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February 27, 2012 02:17PM


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