Returns True if the value of a given attribute or variable is empty.
Null(Attribute | &Variable)
Where:
Attribute
Is an Attribute that should be able to be evaluated in the context where the function is used (it must belong to the Extended Table of the current Base Table, it must be instantiated, etc.).
&Variable
Is a Variable defined in the object where the function is used.
Type Returned:
Boolean (True or False)
Objects: Procedure, Transaction, Web Panel, Panel, Data Provider
Generatos: .NET, .NET Framework, Java, Ruby (up to GeneXus X Evolution 3), RPG, Visual FoxPro (up to GeneXus X Evolution 3), Cobol, Apple, Android,
Angular
Returns True if the value of the attribute or variable is empty.
Consider the following Transaction:
Customer
{
CustomerId*
CustomerName
CustomerAddress
}
Suppose you are asked to query the customers stored with null address. The following For Each command solve the requirement:
For each Customer
where Null(CustomerAddress)
Print Customer /* The printblock contains the attributes: CustomerId, CustomerName*/
Endfor
Nullvalue function
IsNull function
IsEmpty method