DAS

Metadata is:

• redundant data

• data about data

• user created data

• warehoused data

A data model must represent the ____ world as closely as possible.

• machine

• logical

• real

• abstract

The entity integrity rule requires that ____.

• all primary key entries are unique

• a part of the key may be null

• foreign key values do not reference primary key values

• duplicate object values are allowed

The referential integrity rule requires that ____.

• every null foreign key value must reference an existing primary key value

• an attribute have a corresponding value

• every not-null foreign key value reference an existing primary key value

• you delete a row in one table whose primary key does not have a matching foreign key value in another table

Data are classified, according to their format and function, into which categories?

• Numeric and character

• Numeric and logical

• Numeric, character, and date

• Numeric, character, date, and logical

In a relationship, when a primary key from one table is also defined in a second table, the field is referred to as a ____ in the second table.

• combined key

• redundant field

• primary key

• foreign key

A derived attribute ____.

• must be stored physically within the database

• need not be physically stored within the database

• has many values

• must be based on the value of three or more attributes

A ____ key is a key that consists of more than one attribute.

• primary

• foreign

• composite

• domain

A ____ relationship exists when two entities are associated.

• unary

• binary

• ternary

• weak

The set of possible values for an attribute is a ____.

• domain

• range

• set

• weak