Allow Null
(Created page with "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 an question mark at the end of the type, like Boolean? Read more about '''Initial values''' and '''Default Database values''' for a fuller explanation of the properties InitalValue, DefaultDbValue and Allow Null") |
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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 | <message>Write the content here to display this box</message> | ||
'''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?). | |||
Read more about [[Initial values and Default Database values|'''Initial values''' and '''Default Database values''']] for a fuller explanation of the properties [[ | In C# and OCL, it is a bit tricky to know to check for both null and <nowiki>''</nowiki> (empty string) for strings. Hence, the ->isnullorempty operator on string is good to use. | ||
Nullability is at its best for numbers - helping the user to distinguish if someone wrote 0 or no-one has written anything yet... | |||
Read more about [[Documentation:Initial values and Default Database values|'''Initial values''' and '''Default Database values''']] for a fuller explanation of the properties [[Documentation:InitialValue|InitialValue]], [[Documentation:DefaultDBValue|DefaultDBValue]] and Allow Null. | |||
{{Edited|July|12|2025}} | |||
[[Category:Database]] | |||
Latest revision as of 05:05, 13 March 2025
This page was created by Lars.olofsson on 2024-01-16. Last edited by Stephanie 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, it is 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 the 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.