Exam 3: The Relational Database Model

Dr. Codd's rule of relational database states that every value in a table is guaranteed to be accessible through a combination of table name, primary key value, and column name.

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

Describe the use of the INTERSECT operator.

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).

The SELECT operator yields a vertical subset of a table.

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

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

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

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

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

The relationship is the "relational model ideal."

, also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition.

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

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

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

As rare as 1:1 relationships should be, certain conditions absolutely require their use.

RDBMSs enforce integrity rules automatically.

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

are especially useful when you are trying to determine what values in related tables cause referential integrity problems.

The is actually a system-created database whose tables store the user/designer-created database characteristics and contents.