The task queries the lookup source based on the lookup condition that you specify and returns the result of the lookup to the target.

Select a second source when you want to augment the source data with a related value or values from the lookup source. For example, the source is an orders table that contains a customer ID field. You might retrieve the customer name and address from the lookup source so that you can include them in the target object. The task returns all fields from the lookup source.

To optimize performance, the task caches the lookup source. The cache remains static and does not change as the task runs. The task deletes the cache files after the task completes.

You can preview the data in the lookup source. The preview returns the first 10 rows. To preview rows in alphabetical order, select

Display fields in alphabetical order

.

Data Integration

does not change the order of rows in the actual source. You can also download the preview results to a CSV file.

You can also filter the data from both sources before writing it to the target.