Understanding alerts
Obj-List-View method |
Use the Obj-List-View method to execute the retrieval and sorting operations, but not the formatting and display processing, of a list view rule.
Obj-List-View processing can return a smaller set of columns and a more precisely selected set of rows than the similar Obj-List method, and so can require less memory and less network traffic than an Obj-List method.
Specify all three key parts of a list view rule.
Parameter |
Description |
| ObjClass |
Select the Applies To key part of a list view rule. This may identify an internal class or class group, or an external class. |
| ListView |
Select the Purpose key part of a list view rule. |
| Owner |
Select the Owner key part of a list view rule. |
The system uses rule resolution to find the list view rule and executes it, but does not produce any HTML output display. The selection criteria of the list view rule and the sorting requirements (recorded on the Content tab) are converted to an SQL query that is sent to the PegaRULES database.
The database results are organized into a results page of class Code-Pega-List. The name of this page is determined by the Content Page Name field on the Content tab of the List View form, (The Step Page field on the step is ignored.)
Each embedded pages contains the properties listed on the Content tab. If any of these properties is not exposed as a column in the database, the entire Storage Stream (blob) column is accessed. If the Maximum Value field on the Content tab is not blank, the method returns at most the number of embedded pages specified in the Maximum Value field.
Most information in the Organize, Display Field, and Format tabs is not used. However, if report paging is enabled on the Organize tab, only rows for a single page are returned.
This method can return thousands of database rows and create large clipboard pages. Use care to retrieve only the rows (instances) and columns (properties) you truly need.
Execution of this method may cause an alert to be added to the Alert log, of type PEGA004-PEGA007, PEGA0025, PEGA0027. or PEGA0028. Review the Alert log to understand the frequency and sources of such alerts, and for best performance, alter your application or database to eliminate those that occur frequently. For example, if execution of an Obj-List-View method accesses properties within the Storage Stream column, a PEGA0025 alert occurs. The alert indicates that exposing one or more columns in the PegaRULES database table that holds instances of the class is likely to improve performance.
This method updates the pxMethodStatus property. See How to test method results using a transition.
See the PDN article Comparing the Obj-List-View, Obj-Browse and Obj-List methods.
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Alert log, exposed property, results page, Storage Stream |
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About List View rules
Understanding alerts |
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Standard properties in the Code-Pega-List class |