Exam 3: The Relational Database Model

When two or more tables share the same number of columns,and when their corresponding columns share the same or compatible domains,they are said to be .

Each table represents an attribute.

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

A(n)only returns matched records from the tables that are being joined.

In a natural join,the column on which the join was made occurs twice in the new table.

Define entity integrity.What are the two requirements to ensure entity integrity?

If the attribute (B)is functionally dependent on a composite key (A)but not on any subset of that composite key,the attribute (B)is fully functionally dependent on (A).

Date attributes contain calendar dates stored in a special format known as the date format.

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

__ returns only the attributes requested,in the order in which they are requested.

The constraint can be placed on a column to ensure that every row in the table has a value for that column.

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

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

The proper use of keys is crucial to controlling data redundancy.

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

In a database context,the word indicates the use of the same attribute name to label different attributes.

______relationships cannot be implemented as such in the relational model.

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

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

Depending on the sophistication of the application development software,nulls can create problems when functions such as COUNT,AVERAGE,and SUM are used.