Documentation:OCLOperators PSEval: Difference between revisions

OCLOperators PSEval

Revision as of 14:47, 15 October 2023

This page was created by Hans.karlsen@mdriven.net on 2022-01-11. Last edited by Stephanie@mdriven.net on 2025-02-06.

The OCLOperator PSEval makes it possible to use oclPS in any OCL expression. Using this, you can "reach into" the database from OCL and action-language (EAL).

Expression template:

SomeClass.PSEval(<ps-expression>,maxfetch,offset,<dependon>)

Note! PSEval doesn't subscribe to sets from DB. To make the operator auto-updating, provide an expression in "dependon" that, when changed, should also rerun the PSEval expression. This can, for example, be a timer.

Note! Offset is 0-based.

Example:

Uppdrag.PSEval(self.Uppdrag->select(u|u.Aktivt)->orderDescending(u|u.Startdatum),  1000, 0, self.Uppdrag)

For example, this expression from a method has "userName" as a parameter:

SysUser.PSEval(SysUser.allinstances->select(su|su.Username=userName),2,0,'')

Always remember that your SQL-server might also need indexes and other performance settings to execute your expression efficiently.

Note! The offset parameter should almost always be 0, if not used to show a seconds page in a pagination or similar.

@@ Line 1: / Line 1: @@
-A way to switch from ocl to oclps in any expression
+The OCLOperator PSEval makes it possible to use oclPS in any OCL expression. Using this, you can "reach into" the database from OCL and action-language (EAL).
+Expression template:
+ SomeClass.PSEval(<ps-expression>,maxfetch,offset,<dependon>)
+'''Note!''' PSEval doesn't subscribe to sets from DB. To make the operator auto-updating, provide an expression in "dependon" that, when changed, should also rerun the PSEval expression. This can, for example, be a timer.
+'''Note!''' Offset is 0-based.
+Example:
+ Uppdrag.PSEval(self.Uppdrag->select(u|u.Aktivt)->orderDescending(u|u.Startdatum),  1000, 0, self.Uppdrag)
+For example, this expression from a method has "userName" as a parameter:
+ SysUser.PSEval(SysUser.allinstances->select(su|su.Username=userName),2,0,<nowiki>''</nowiki>)
+Always remember that your SQL-server might also need indexes and other performance settings to execute your expression efficiently.
+'''Note!''' The offset parameter should almost always be 0, if not used to show a seconds page in a pagination or similar.
+See also: [[OCLOperators Sqlpassthrough|Sqlpassthrough]], [[OCLOperators PSEvalValue|PSEvalValue]], [[OCLOperators PSEvalTuples|PSEvalTuples]]
+[[Category:OCLOperators]]