Exam 3: The Relational Database Model

What is a key and why is it important in the relational model?

All RDBMSs enforce integrity rules automatically.

Any attribute that is part of a key is known as a ____.

The ____________________ catalog can be described as a detailed system data dictionary that describes all objects within the database,including data about table names,the table's creator and creation date,the number of columns in each table,the data type corresponding to each column,index filenames,index creators,authorized users,and access privileges.

Attribute A determines attribute B (that is,B is functionally ____________________ on A)if all of the rows in the table that agree in value for attribute A also agree in value for attribute B.

A ____ key can be described as a superkey without unnecessary attributes,that is,a minimal superkey.

The DIVIDE operation uses one single-column table (i.e.column "a")as the divisor and one two-column table (i.e.columns "a" and "b")as the dividend.

If one department chair-a professor-can chair only one department and one department can have only one department chair,then the entities PROFESSOR and DEPARTMENT exhibit a(n)____________________ relationship.

A(n)____________________ key can be described as a superkey without unnecessary attributes.

In the following table description,____ is the primary key. PRODUCT (PROD_CODE,PROD_DESCRIPT,PROD_PRICE,PROD_ON_HAND,VEND_CODE)

The relational database model enables you to view data ____ rather than ____.

The equijoin takes its name from the comparison operator ____ used in the condition.

____________________ relationships can be implemented by creating a new entity in 1:M relationships with the original entities.

The ____ relationship should be rare in any relational database design.

A ____ key is defined as a key that is used strictly for data retrieval purposes.

The order of the rows and columns is important to the DBMS.

The index key can have multiple attributes,this is called a(n)____________________ index.

The practical significance of taking the logical view of a database is that it serves as a reminder of the simple file concept of data storage.

____ relational type is the "relational model ideal."

A CUSTOMER table's primary key is CUS_CODE.The CUSTOMER primary key column has no null entries,and all entries are unique.This is an example of ____ integrity.