entitySelection[index]

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4D v19.8


entitySelection[index] -> Result

Parameter	Type	Description
Result	Entity	Entity corresponding to the specified index (non assignable expression)

Description

The entitySelection[index] notation allows you to access entities within the entity selection using the standard collection syntax: pass the position of the entity you want to get in the index parameter.

Note that the corresponding entity is reloaded from the datastore.

index can be any number between 0 and entitySelection.length-1.

If index is out of range, an error is returned.
If index corresponds to a dropped entity, a Null value is returned.

Warning: entitySelection[index] is a non assignable expression, which means that it cannot be used as en editable entity reference with methods like entity.lock( ) or entity.save( ). To work with the corresponding entity, you need to assign the returned expression to an assignable expression, such as a variable. Examples:

 $sel:=ds.Employee.all() //create the entity selection

  //invalid statements:

 $result:=$sel[0].lock() //will NOT work

 $sel[0].lastName:="Smith" //will NOT work

 $result:=$sel[0].save() //will NOT work

  //valid code:

 $entity:=$sel[0]  //OK

 $entity.lastName:="Smith" //OK

 $entity.save() //OK

Example

 C_OBJECT($employees;$employee)

 $employees:=ds.Employee.query("lastName = :1";"H@")

 $employee:=$employees[2]  // The 3rd entity of the $employees entity selection is reloaded from the database