EntityDAC

TCustomEntityContext.CreateEntity<T> Method

The method is designed for creating a new entity instance.

Class

TCustomEntityContext

Syntax

function CreateEntity<T: TMappedEntity>(const KeyValue: Variant): T; overload;

Type parameters
T
The class type of the entity to be created
Parameters
KeyValue
The initial value of the primary key meta attribute.

Remarks

The method creates a new entity instance of the specified class type. The entity primary key attribute will be initialized by the specified value. The entity instance created by this method is not attached to the data context (is not placed to the object cache), therefore it won't be automatically destroyed on application shutdown. It should be destroyed manually. It is expedient to use the method in case when the primary key value of an entity is unknown at the moment of its creation (or there is no confidence in its uniqueness), in order to avoid an exception on an attempt to place an object to the cache.

To attach an entity instance to the data context and place it to the object cache (in order to perform further modification operations: TCustomEntityContext.Delete, TCustomEntityContext.Save, TCustomEntityContext.Cancel), the TCustomEntityContext.Attach method should be used. To create an entity instance with simultaneous attaching it to the data context, the TCustomEntityContext.CreateAttachedEntity method should be used.

Example

var
  EmpEntity: TEntity;
begin
EmpEntity := Context.CreateAttachedEntity<TEmp>(1);
  // ...
end; 

See Also

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