This is the legacy 4D documentation web site. Documentations are progressively being moved to developer.4d.com
- 4D Language Reference
-
- ORDA - EntitySelection
-
-
entitySelection.{attributeName}
-
entitySelection.add( )
-
entitySelection.and( )
-
entitySelection.average( )
-
entitySelection.contains( )
-
entitySelection.copy( )
-
entitySelection.count( )
-
entitySelection.distinct( )
-
entitySelection.drop( )
-
entitySelection.extract( )
-
entitySelection.first( )
-
entitySelection.getDataClass( )
-
entitySelection.isAlterable( )
-
entitySelection.isOrdered( )
-
entitySelection.last( )
-
entitySelection.length
-
entitySelection.max( )
-
entitySelection.min( )
-
entitySelection.minus( )
-
entitySelection.or( )
-
entitySelection.orderBy( )
-
entitySelection.orderByFormula( )
-
entitySelection.query( )
-
entitySelection.queryPath
-
entitySelection.queryPlan
-
entitySelection.refresh( )
-
entitySelection.slice( )
-
entitySelection.sum( )
-
entitySelection.toCollection( )
-
entitySelection[index]
-
Create entity selection
-
USE ENTITY SELECTION
-
entitySelection.first( )
| entitySelection.first () -> Result | ||||||||
| Parameter | Type | Description | ||||||
| Result | Entity, Null |
|
Reference to the first entity of the entity selection | |||||
The entitySelection.first( ) method returns a reference to the entity in the first position of the entity selection.
The result of this method is similar to:
$entity:=$entitySel[0]There is, however, a difference between both statements when the selection is empty:
C_OBJECT($entitySel;$entity)
$entitySel:=ds.Emp.query("lastName = :1";"Nonexistentname") //no matching entity
//entity selection is then empty
$entity:=$entitySel.first() //returns Null
$entity:=$entitySel[0] //generates an error C_OBJECT($entitySelection;$entity)
$entitySelection:=ds.Emp.query("salary > :1";100000)
If($entitySelection.length#0)
$entity:=$entitySelection.first()
End if
entity.first( )
entitySelection.last( )
entitySelection[index]
Product: 4D
Theme: ORDA - EntitySelection
Created: 4D v17
4D Language Reference ( 4D v19)
4D Language Reference ( 4D v19.1)
4D Language Reference ( 4D v19.4)
4D Language Reference ( 4D v19.5)
4D Language Reference ( 4D v19.6)
4D Language Reference ( 4D v19.7)
4D Language Reference ( 4D v19.8)
