REF (Entity SQL)
Returns a reference to an entity instance.
REF( expression )
Arguments
- expression
Any valid expression that yields an instance of an entity type.
Return Value
A reference to the specified entity instance.
Remarks
An entity reference consists of the entity key and an entity set name. Because different entity sets can be based on the same entity type, a particular entity key can appear in multiple entity sets. However, an entity reference is always unique. If the input expression represents a persisted entity, a reference to this entity will be returned. If the input expression is not a persisted entity, a null reference will be returned.
If the property extraction operator (.) is used to access a property of an entity, the reference is automatically dereferenced.
Example
The following Entity SQL query uses the REF operator to return the reference for an input entity argument. The same query dereferences the reference because we are using a property extraction operation (.) to access a property of the Product entity. The query is based on the AdventureWorks Sales Model. To compile and run this query, follow these steps:
Follow the procedure in How to: Execute a Query that Returns PrimitiveType Results (EntityClient).
Pass the following query as an argument to the
ExecutePrimitiveTypeQuerymethod:
SELECT VALUE REF(p).Name FROM AdventureWorksEntities.Product as p
This example produces the following output:
Value: Adjustable Race
Value: All-Purpose Bike Stand
Value: AWC Logo Cap
Value: BB Ball Bearing
Value: Bearing Ball
See Also
Reference
DEREF (Entity SQL)
CREATEREF (Entity SQL)
KEY (Entity SQL)