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Learn more about the logical functions AND, OR, NOT, logical values TRUE, FALSE, and the special meta-value UNKNOWN.
Overview
Function / value | Description |
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AND | Returns |
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AND
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TRUE if all its arguments evaluate to TRUE; it returns FALSE if one or more arguments evaluate to FALSE. |
Syntax
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argument1 AND argument2 [AND ...] |
- argument1 - The first boolean condition that you want to evaluate.
- argument2 - The first boolean condition that you want to evaluate.
- [AND …] - Additional boolean conditions that you want to evaluate. (optional)
Return type
- boolean
Examples
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FALSE
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OR
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TRUE
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TRUE if at least one of its arguments evaluates to TRUE; it returns FALSE if none of the arguments evaluate to TRUE. |
Syntax
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argument1 OR argument2 [OR ...] |
argument1 - The first boolean condition that you want to evaluate. argument2 - The first boolean condition that you want to evaluate. [OR …] - Additional boolean conditions that you want to evaluate.
Return type
- boolean
Examples
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Use the '?' (question mark), representing UNKNOWN, to check if an expression or an attribute has a value. |
TRUE | This is the boolean value TRUE. |
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FALSE | This is the boolean value FALSE. |
Functions
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NOT
This operator reverses the value of its boolean argument.
Syntax
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NOT argument |
- argument - The boolean condition of which you want to reverse its value.
Return type
- boolean
Examples
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Tip |
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Using brackets is not required, but advised to clearly indicate which boolean condition needs to be reversed. |
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UNKNOWN
You can use the '?' (question mark), representing UNKNOWN, to check if an expression or an attribute has a value.
Example
Suppose a model with an entity Person and attributes Person.name and Person.age. In runtime, a user fills out a form and enters his name, but forgets to fill out his age.
As a result:
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