Documentation:Allow Null: Difference between revisions

Allow Null

Revision as of 05:39, 20 January 2025

This page was created by Lars.olofsson@mdriven.net on 2024-01-16. Last edited by Stephanie@mdriven.net on 2025-03-13.

Allow null sets an attribute's nullability, i.e. if this attribute should be able to hold "no value". It affects both the in-memory value (it will show up with a question mark at the end of the type, like Boolean?).

In c# and ocl its a bit tricky to know to check for both null and '' (empty string) for strings - hence the ->isnullorempty operator on string is good to use.

Nullability is at its best for numbers - helping user to distinguish if someone wrote 0 or no-one has written anything yet...

Read more about Initial values and Default Database values for a fuller explanation of the properties InitialValue, DefaultDBValue and Allow Null

Revision as of 14:34, 20 December 2024 (view source) Hans.karlsen@mdriven.net (talk \| contribs) No edit summary Tag: Visual edit ← Older edit		Revision as of 05:39, 20 January 2025 (view source) Edgar (talk \| contribs) (Updated Edited template to July 12, 2025.) Newer edit →
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	Read more about [[Initial values and Default Database values\|'''Initial values''' and '''Default Database values''']] for a fuller explanation of the properties [[InitialValue]], [[DefaultDBValue]] and [[Allow Null]]		Read more about [[Initial values and Default Database values\|'''Initial values''' and '''Default Database values''']] for a fuller explanation of the properties [[InitialValue]], [[DefaultDBValue]] and [[Allow Null]]
	{{Edited\|July\|12\|~~2024~~}}		{{Edited\|July\|12\|2025}}