Ds1 (12m recs) as input stream to lookup stage. Ds2 (13k recs) as reference stream to a lookup stage. Use vhc as lookup key.
This section specifies the minimum steps to take to get a modify stage functioning. The input tab allows you to specify details about the incoming data set you are modifying. The change apply stage reads a record from the change data set and from the before data set, compares their key column values, and acts accordingly:
If the before keys come before the change keys in the specified sort order, the before record is copied to the output. The change record is retained for the next comparison. The change capture stage is intended to be used in conjunction with the change apply stage;
It produces a change data set which contains changes that need to be applied to the before data set to turn it into the after data set. The difference stage outputs the before and after rows to the output data set, plus a code indicating if there are. This section specifies the minimum steps to take to get a change apply stage functioning.
Specifies to drop (not generate) the output row for a copy result. By default, an output row is not created by the stage. 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. 32 rowsa datastage® flow consists of stages that are linked together, which describe the flow of data. The change capture stage takes two input data sets, denoted before and after, and outputs a single data set whose records represent the changes made to the before data set to obtain the after data set.
The stage produces a change data set, whose table definition is transferred from the after data set's table definition with the addition of one. This section specifies the minimum steps to take to get a change apply stage functioning. On the output tab, you can specify details about data output from the modify stage.
The sections on the output tab allow you specify various options for the link. The columns section specifies the column definitions of the data. The maps from column input column section that appears when you click edit in the columns section allows you to.
It captures the change between two input data by comparing them based on key column. The two input links are linked with change capture stage by the two default link names i. e. The stage produces a change data set, whose table definition is transferred from the after data set’s table.
The difference stage returns the before columns and after columns only in some situations (if they are not part of the key or value columns and are named differently) the change capture stage returns the after columns. Before columns are only available for deletes. Answered nov 28, 2018 at 19:21.
The change apply stage is a processing stage. It takes the change data set, that contains the changes in the before and after data sets, from the change capture stage and applies the encoded change operations to a before data set to compute an after data set. (see change capture stage for a description of the change capture stage. )
When you create and edit transform jobs with the datastage service, you have numerous stages to work with. You use the stages to transform the data in useful ways. The stages are easy to add to the job by dragging them from the palette to the canvas.
You can also configure the stages by clicking them to open the details card on the transform data page of datastage. The following table contains the change data set, as output by a change capture stage: The following table contains the after data set, output by the change apply stage (bcol4 is the key column, bcol1 the value column):
