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Change Capture stage: Stage tab (DataStage)

Last updated: Mar 12, 2025
Change Capture stage: Stage tab (DataStage)

The Stage tab allows you to specify an optional description of the stage.

The Properties section lets you specify what the stage does. The Advanced section allows you to specify how the stage executes.

Properties

The following table lists the properties and their attributes:
Table 1. Properties
Category/Property Values Default Mandatory? Repeats? Dependent of
Change Keys/Key Input Column N/A Y Y N/A
Change Keys/Case Sensitive True/False True N N Key
Change Keys/Sort Order Ascending/ Descending Ascending N N Key
Change Keys/Nulls Position First/Last First N N Key
Change Values/Value Input Column N/A N Y N/A
Change Values/Case Sensitive True/False True N N Value
Options/Change Mode Explicit Keys & Values/All keys, Explicit values/Explicit Keys, All Values Explicit Keys & Values Y N N/A
Options/Log Statistics True/False False N N N/A
Options/Drop Output for Insert True/False False N N N/A
Options/Drop Output for Delete True/False False N N N/A
Options/Drop Output for Edit True/False False N N N/A
Options/Drop Output for Copy True/False True N N N/A
Options/Code Column Name string N/A N N N/A
Options/Copy Code number 0 N N N/A
Options/Deleted Code number 2 N N N/A
Options/Edit Code number 3 N N N/A
Options/Insert Code number 1 N N N/A

Change Keys category

Specifies the name of a difference key input column.
Key
This property can be repeated to specify multiple difference key input columns. You can use the Column Selection dialog box to select several keys at once if required. Key has the following dependent properties:
  • Case Sensitive

    Use this property to specify whether each key is case sensitive or not. It is set to True by default; for example, the values "CASE" and "case" would not be judged equivalent.

  • Sort Order

    Specify ascending or descending sort order.

  • Nulls Position

    Specify whether null values should be placed first or last.

Change Value category

Value
Specifies the name of a value input column. You can use the Column Selection dialog box to select values at once if required . Value has the following dependent properties:
  • Case Sensitive

    Use this to property to specify whether each value is case sensitive or not. It is set to True by default; for example, the values "CASE" and "case" would not be judged equivalent.

Options

Use the Options category to specify how the Change Capture stage operates.
Change mode
This mode determines how keys and values are specified. Choose Explicit Keys & Values to specify the keys and values yourself. Choose All keys, Explicit values to specify that value columns must be defined, but all other columns are key columns unless excluded. Choose Explicit Keys, All Values to specify that key columns must be defined but all other columns are value columns unless they are excluded.
Log statistics
This property configures the stage to display result information containing the number of input rows and the number of copy, delete, edit, and insert rows.
Drop output for insert
Specifies to drop (not generate) an output row for an insert result. By default, an output row is always created by the stage.
Drop output for delete
Specifies to drop (not generate) the output row for a delete result. By default, an output row is always created by the stage.
Drop output for edit
Specifies to drop (not generate) the output row for an edit result. By default, an output row is always created by the stage.
Drop output for copy
Specifies to drop (not generate) the output row for a copy result. By default, an output row is not created by the stage.
Code column name
Allows you to specify a different name for the output column carrying the change code generated for each record by the stage. By default the column is called change_code.
Copy code
Allows you to specify an alternative value for the code that indicates the after record is a copy of the before record. By default this code is 0.
Deleted code
Allows you to specify an alternative value for the code that indicates that a record in the before set has been deleted from the after set. By default this code is 2.
Edit code
Allows you to specify an alternative value for the code that indicates the after record is an edited version of the before record. By default this code is 3.
Insert code
Allows you to specify an alternative value for the code that indicates a new record has been inserted in the after set that did not exist in the before set. By default this code is 1.

Advanced

Specify the following advanced parameters:
  • Execution Mode. The stage can execute in parallel mode or sequential mode. In parallel mode the input data is processed by the available nodes as specified in the Configuration file, and by any node constraints specified on the Advanced tab. In Sequential mode the entire data set is processed by the conductor node.
  • Combinability mode. This is Auto by default, which allows IBM® DataStage® to combine the operators that underlie parallel stages so that they run in the same process if it is sensible for this type of stage.
  • Preserve partitioning. This is Propagate by default. It adopts Set or Clear from the previous stage. You can explicitly select Set or Clear. Select Set to request that next stage in the job should attempt to maintain the partitioning.