This is the legacy 4D documentation web site. Documentations are progressively being moved to developer.4d.com
- 4D Language Reference
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- SQL
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Overview of SQL Commands
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On SQL Authentication Database Method
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Begin SQL
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End SQL
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Is field value Null
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QUERY BY SQL
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SET FIELD VALUE NULL
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SQL CANCEL LOAD
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SQL End selection
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SQL EXECUTE
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SQL EXECUTE SCRIPT
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SQL EXPORT DATABASE
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SQL EXPORT SELECTION
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SQL Get current data source
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SQL GET DATA SOURCE LIST
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SQL GET LAST ERROR
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SQL GET OPTION
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SQL LOAD RECORD
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SQL LOGIN
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SQL LOGOUT
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SQL SET OPTION
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SQL SET PARAMETER
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START SQL SERVER
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STOP SQL SERVER
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Is field value Null
| Is field value Null ( aField ) -> Function result | ||||||||
| Parameter | Type | Description | ||||||
| aField | Field |
|
Field to be evaluated | |||||
| Function result | Boolean |
|
True = field is NULL, False = field is not NULL | |||||
The Is field value Null command returns True if the field designated by the aField parameter contains the NULL value, and False otherwise.
The NULL value is used by the SQL kernel of 4D. For more information, refer to the 4D SQL Reference manual.
The value returned by this command is only meaningful if the "Map NULL values to blank values" option is not checked in the field definition of the Structure editor. Otherwise, it always returns False.
Note: This command cannot be used with objects and object properties. Null values in object fields are handled through the Null command.
Product: 4D
Theme: SQL
Number:
964
Created: 4D v11 SQL
4D Language Reference ( 4D v20 R7)
