How to only export to text where data exist

  • SQL Server 2008

    My package generates a table of data and then exports it to disk. I only want the export to happen if there are data in the table - i.e. I do not want to produce an empty file. There's an Execute SQL task after the export that I don't want to run either. I know I could test for the presence of data within an Execute SQL task and call RAISEERROR if the table was empty, but don't want to have errors showing up anywhere if I don't have to. How do I implement this kind of control flow in SSIS?

    Thanks

    Scott

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    Scott

  • I would recommend getting the row count from your table and populating a variable with it. Use that variable inside a precedence constraint. Use an expression to test for a non zero value in an expression on the precedence constraint.

    If you've used a Data Flow to populate your table, simply use the Row Count transformation just before your destination adapter to get the row count into a variable. If you've not used a Data Flow, you'll need to call another ExecuteSQL task and return the results into a variable from there. Either way, it's pretty straight forward.

    John Rowan

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    Forum Etiquette: How to post data/code on a forum to get the best help[/url] - by Jeff Moden

  • I hadn't known about expressions in constraints until now. It is straightforward, isn't it?

    Thanks

    --
    Scott

  • Yes. In your Control Flow, just double-click on the connector and it will bring up the Precedence Constraint Editor. For the Evaluation Operation, you'll want to use Expression and Constraint. Set the Value option to Success and build your Expression in the Expression box.

    John Rowan

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    Forum Etiquette: How to post data/code on a forum to get the best help[/url] - by Jeff Moden

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