6) Mary Lamb is an insurance sales representative. Her company has provided her with a laptop computer that uses wireless connectivity to access the accounting information system from virtually anywhere in the country. She has access to view customer and insurance product information. She also has access that allows her to enter and cancel customer orders. The permissions for Mary (and other sales reps) define a in the company's database management system.

external-level schema

Explanation:

Mary lamb is an insurance sales representative. Her company has provided her with a laptop computer that uses wireless connectivity to access the accounting information system from virtually anywhere in the country. She has access to view customer and insurance product information. She also has access that allows her to enter and cancel customer orders. The permissions for Mary (and other sales reps) define a  schema in the company's database management system.

An external schema can be defined access to the aspect of a database that concerns a particular user or group of users. hence a certain aspect of data has been prepared to meet the needs of that particular group and they are given access (external access) to just that aspect of the data management system.

subschema

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.

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