Exam 3: The Relational Database Model

Referential dictates that the foreign key must contain values that match the primary key in the related table,or must contain null.

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

A contains at least all of the attribute names and characteristics for each table in the system.

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

Only a single attribute,not multiple attributes,can define functional dependence.

Another name for a composite entity is a(n)entity.

Each table in a relational database must have a primary key.

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.

The relationship should be rare in any relational database design.

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

In a database context,a(n)indicates the use of different names to describe the same attribute.

Describe the use of the INTERSECT operator.

A is any key that uniquely identifies each row.

One characteristic of generalization hierarchies is that they are implemented as relationships.

What is a key and how is it important in a relational model?

Define an index.Explain the role of indexes in a relational database.

A(n)provides a detailed description of all tables found within the user/designer-created database.

An index key can have multiple (a composite index).

To be considered minimally relational,the DBMS must support the key relational operators ,PROJECT,and JOIN.

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