SSIS: Control Flow

Control Flow:

1.Control flow consists of one or more tasks and containers that execute when the package runs. We use precedence constraints to connect the tasks and containers in a package. 

SSIS provides 3 different types of control flow elements: 

-Containers that provide structures in packages. 

-Tasks that provide functionality. 

-Precedence Constraints that connect the executables, containers, and tasks into an ordered control flow.

2. Control flow does not move data from task to task.

3. Tasks are run in series if connected with precedence or in parallel.

Precedence Constraints:

 A task will only execute if  the condition that is set by the precedence constraint preceding the task is met. By using these constraints,it will choose different execution paths depending on the success or failure of other tasks. 

1. Success: Workflow will proceed when the preceding container executes successfully. Indicated in control flow by a solid green line.

2. Failure: Workflow will proceed when the preceding container’s execution results in a failure. Indicated in control flow by a solid red line.

3. Completion: Workflow will proceed when the preceding container’s execution completes, regardless of success or failure. Indicated in control flow by a solid blue line.

4. Expression/Constraint with Logical AND: Workflow will proceed when specified expression and constraints evaluate to true. Indicated in control flow by a solid color line along with a small ‘fx’ icon next to it. Color of line depends on logical constraint chosen (e.g. success=green, completion=blue).

5. Expression/Constraint with Logical OR: Workflow will proceed when either the specified expression or the logical constraint (success/failure/completion) evaluates to true. Indicated in control flow by a dotted color line along with a small ‘fx’ icon next to it. Color of line depends on logical constraint chosen (e.g. success=green, completion=blue).