Precedence Constraints: how to control the flow of task execution

Precedence Constraints are arrows in the Control Flow which define execution priority of tasks and other executables in the Control Flow. In the samples of this book till now we used simple Precedence Constraints a lot.

In this recipe, we will explore a new way of using Precedence Constraints and we will implement an if condition in the Control Flow with Precedence Constraints.

Also, we will reveal options to work when there are multiple Precedence Constraints for each executable.

How to do it...

1. Create a SSIS project and name it as R06_Precedence Constraints.

2. Create a RecordCount package variable of type int32. Set the default value to 0.

3. Add an Execute SQL Task into the Control Flow, create an OLE DB Connection to the AdventureWorks2008R2 database.

4. Type the following query in the SQL Statement property:

   SELECT COUNT(*) AS Cnt
   FROM Sales.Customer
   WHERE DATEDIFF(Day, ModifiedDate, GETDATE()) < 0

5. As the previous statement will return...