Answer:
subschema
Step-by-step explanation:
To define a subschema, we first must define a schema in a database management system. Schema refers to the overall database design, and is usually fixed, since it is usually not changed frequently. A subschema is subset of the database's schema, and it is used by programmers to view and record data item types.
In simple words, the schema is the whole database design which users cannot generally access, instead users access the database through subschemas. Since Mary accesses the database, she must do so through a subschema.