Exam 3: The Relational Database Model

The SELECT operator yields a vertical subset of a table.

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

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.

Referential and entity integrity are two names for the same thing.

In an outer join,the matched pairs would be retained and any unmatched values in the other table would be left ____.

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

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.

The one-to-many (1:M)relationship is easily implemented in the relational model by putting the foreign key of the "1" side in the table of the "many" side as a primary key.

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

____________________ joins are especially useful when you are trying to determine what value(s)in related tables cause(s)referential integrity problems.

The ____________________ relationship is the relational database norm.

If the foreign key contains either matching values or nulls,the table that makes use of that foreign key is said to exhibit ____________________ integrity

A(n)____ is an ordered arrangement of keys and pointers.

Current relational database software generally provides only a system catalog (and not a data dictionary).

Codd's Rule of ____ states: Application programs and ad hoc facilities are logically unaffected when changes are made to the table structures that preserve the original table values (changing order of columns or inserting columns).

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

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

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

What is the system catalog?

Since it is used to link the tables that originally were related in a M:N relationship,the composite entity structure includes-as foreign keys-at least the ____ keys of the tables that are to be linked.