Replicate - How to store before-image data in target table

[john_wang]

Sometimes we need to store column's before-image data in the target table. This is useful  if we want to store both of the before-image and after-image of the columns values in the target table for downstream apps usage. 

 

Environment

• Qlik Replicate All supported versions

Detailed Steps:

Under Apply Changes mode (Store changes mode is turn off),  in the table setting by adding a new column in transformation (name it as "prevenient_salary" in this sample), the variable expression is like $BI__<columnName> where $BI__ is a mandatory prefix (which instructs Replicate to capture the before-image data) and <columnName> is the original table column. For example if the original table column name is SALARY then $BI__SALARY is the column before-image data:

    

If the column SALARY value is updated from 22 to 33 in source side, then before the UPDATE the target table row looks like:

    

after the UPDATE is applied to target table the row looks like:

    

In this sample the before-image value is 22, the after-image value is 33.

Related Content

before-image data can be used in filer also, see sample here .

Qlik Replicate 

[Solomon]

Hi, Will this work on CT table in the store changes mode also? 

[john_wang]

Hello @Solomon ,

Thanks for the update.

Yes, it works however by design both Before Image & After Image of change row are recorded in the __ct table already, unless it's turned off. A sample of task setting:

Regards,

John.