Version: 0.2 2017.11.28 AET
Using EXPRESS_EXTENSION_SCHEMA from QUERY SCHEMA
To enable compile-time checking and binding an EDM query schema must specify which extension schemata it depends on by specifying the extension as follows in the GLOBAL section:
The "schema_instance" declaration name "ex1" has no use further in the query schema. Constructs from the specified extension will be imported into compiler enabling named access from the query scschema code.