Exam 3: The Relational Database Model

A(n) _____ join links tables by selecting only the rows with common values in their common attribute(s).

A(n) _____ index is an index in which the index key can have only one pointer value (row) associated with it.

The relational operators have the property of _____; that is, the use of relational algebra operators on existing relations (tables) produces new relations.

_____ relationships cannot be implemented as such in the relational model.

The 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.

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

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.

RDBMSs enforce integrity rules automatically.

In a relational table, each column has a specific range of values known as the _____ domain.

You can think of a table as a persistent representation of a logical relation.

A null is created when you press the Enter key or the Tab key to move to the next entry without making a prior entry of any kind.

Character data can contain any character or symbol intended for mathematical manipulation.

A(n) _____ is an orderly arrangement used to logically access rows in a table.

Describe the use of null values in a database.

A data dictionary is sometimes described as "the database designer's database" because it records the design decisions about tables and their structures.

When you define a table's primary key, the DBMS automatically creates a(n) _____ index on the primary key column(s) you declared.

To avoid nulls, some designers use special codes, known as _____, to indicate the absence of some value.

PRODUCT yields all possible pairs of rows from two tables, also known as the _____ product.

A(n) _____ links tables on the basis of an equality condition that compares specified columns of each table.

According to Codd's _____ rule of relational databases, if the system supports low-level access to the data, users must not be allowed to bypass the integrity rules of the database.