The final thing that we are going to look at in this introductory tutorial is Precedence Constraints.
Figure 1.21 Creating a Precedence Constraint.
An example of a precedence constraint would be if we had say an ExecuteSQL task that bulit a table for us and we had a Data Pump that loaded it with data. We want the table to be created before we try to send data to it otherwise it will fail. In addition to this we only want to send data if the table creation succeeds. Time for the precedence constraint.
There are three types of constraint.
1. On Completion. The task following the constraint will happen when the preceding one finishes regardless of outcome.(Blue Chequered Line).
2. On Success. The task following the constraint will happen when the preceding one Succeeds.(Green Chequered Line).
1. On Failure. The task following the constraint will happen when the preceding one Fails.(Red Chequered Line).
Figure 1.22 Shows an on Completion constraint set up.
Figure 1.22 On Completion Constraint.
As you can see a DTS package is a pretty complex thing and in this tutorial we've only scratched the surface. In later ones we are going to be taking
a closer look at packages and seeing how to use some of the features we have mentioned here to their full potential.