The correct answer is: D. All of the above
A data dictionary is a repository of information about data used in an organization. It contains definitions of data elements, their relationships to each other, and the rules and constraints that apply to them. The data dictionary is used by the database management system (DBMS) to manage the database.
The data dictionary tells the DBMS what files are in the database. This information is used by the DBMS to locate the data when it is needed. The data dictionary also tells the DBMS what attributes are possessed by the data. This information is used by the DBMS to enforce data integrity constraints. The data dictionary also tells the DBMS what these files contain. This information is used by the DBMS to generate reports and to answer queries.
Here is a brief explanation of each option:
- Option A: The data dictionary tells the DBMS what files are in the database. This information is used by the DBMS to locate the data when it is needed. For example, if the data dictionary contains a record for a file called “Customers,” the DBMS will know that the Customers file contains information about customers.
- Option B: The data dictionary tells the DBMS what attribute are possessed by the data. This information is used by the DBMS to enforce data integrity constraints. For example, if the data dictionary contains a record for an attribute called “Customer Name,” the DBMS will know that the Customer Name attribute must be unique for each customer.
- Option C: The data dictionary tells the DBMS what these files contain. This information is used by the DBMS to generate reports and to answer queries. For example, if the data dictionary contains a record for a file called “Orders,” the DBMS will know that the Orders file contains information about orders.
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