Filter By Expression component

Posted by Ab Initio Coach at 3:47:00 AM

Filter By Expression component in ab initio with example and real time parameters

Purpose
Filter by Expression filters records according to a DML expression or transform function, which specifies the selection criteria.
Filter by Expression is sometimes used to create a subset, or sample, of the data. For example, you can configure Filter by Expression to select a certain percentage of records, or to select every third (or fourth, or fifth, and so on) record. Note that if you need a random sample of a specific size, you should use the sample component.
FILTER BY EXPRESSION supports implicit reformat. For more information, see “Implicit reformat”.
Recommendation
Component folding can enhance the performance of this component. If this feature is enabled, the Co>Operating System folds this component by default. See “Component folding” for more information.
Location in the Component Organizer
Transform folder
Runtime behavior of FILTER BY EXPRESSION
Filter by Expression does the following:

Reads data records from the in port.

If the use_package parameter is false, applies the expression in the select_expr parameter to each record. It routes records as follows, based on how the expression evaluates:

For a non-0 value, Filter by Expression writes the record to the out port.

For 0, Filter by Expression writes the record to the deselect port. If you do not connect a flow to the deselect port, Filter by Expression discards the records.

For NULL, Filter by Expression writes the record to the reject port and a descriptive error message to the error port

If the use_package parameter is true, executes the functions defined in the package

If output_for_error or make_error is defined, executes them whenever an error event occurs. If log_error is defined and logging of rejects is turned on, executes log_error.

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