Hi,
Direct Extraction & Criteria in IDEA both serve the same purpose. They allow the user to apply arithmetical, logical, conditional commands through the Equation Editor. Very useful to extract data which meets a particular requirement like all sales booked without a valid sales order.
The key differences between Direct Extraction & Criteria are -
a. Direct Extraction creates a separate child database through its criteria whereas Criteria creates a display or view.
b. You can apply up to 50 Direct Extractions at the same time through a single pass of the parent database whereas you can apply only one Criteria at a time on an active database.
c. If you do not save the Direct Extraction criteria/command in the Equation Editor you lose the criteria command once you delete the child database arising out of a direct extraction. However once you enter a Criteria and clear it the last few Criteria entered on the parent database continue to remain in the Criteria. Just right click on Criteria under the Properties and view the last Criteria entered.
d. Direct Extraction allows you the facility to select output fields to display and also run the command on a specific range (record # 1 to say record # 50000 as an example). Criteria runs the command on the entire parent database and returns a view/display with all fields.
e. Direct Extraction is recommended for usage when you are sure about your command and are expected to receive a definitive result in the form of the child database. Criteria is useful for exploratory or what if analysis.
You can convert a criteria to a child database by clicking on Save As under the Home tab. But once saved do remember to clear the criteria entered on the parent database lest you run the next analytic test on the display/view from the earlier criteria.
Kind Regards
Jairam