Attribute Visibility

Within the current query scope, you can access any available object or object attribute.

In querying, an object's attribute is any identifier that can be mapped to a public field or method in the object.

In the FROM specification, any object that is in scope is valid, so at the beginning of a query all cached regions and their attributes on the cache server are in scope.

This query is valid because name resolves to the Region method getName:

/portfolios.name

This query is valid because toArray resolves to the Collection method with the same name:

SELECT DISTINCT * FROM /portfolios.toArray

You cannot, however, refer to the attribute of a collection object in the region path expression where the collection itself is specified. The following statement is invalid because neither Collection nor Region contain an attribute named positions. The entry values collection (specified by /portfolios) that does contain an attribute named positions is not yet part of the query name space.

/* INCORRECT: positions is not an attribute of Region or of Collection */
SELECT DISTINCT * FROM /portfolios.positions

The following SELECT statement is valid because positions is an element of the entry value collection that is specified by /portfolios. The entry value collection is in scope as soon as the specification in the FROM expression is complete (before WHERE or SELECT are evaluated).

SELECT DISTINCT positions FROM /portfolios

You can also refer to positions inside the FROM clause after the /portfolios entry value collection is created. In this example, positions is an element of the /portfolios entry value collection and values is an attribute of positions:

IMPORT javaobject.Position;
SELECT DISTINCT posnVal
FROM /portfolios, positions.values posnVal TYPE Position
WHERE posnVal.mktValue >= 25.00

After the comma in the FROM clause, /portfolios is in scope, so its value collection can be iterated. In this case, this is done with the second FROM clause specification, positions.values.