Pop quiz W3

The columns of a relation

• must be in specified order

• may be in any order

• with key field in first column

• with largest width column last

In a relational table, each column represents an attribute and each column has a distinctive name.

• TRUE

• FALSE

To maintain entity integrity, a null value is permitted in the primary key.

• TRUE

• FALSE

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

.   _______ symbol is used to denote the CROSS PRODUCT operation.

• X

• σ

• ρ

• π

_________ is

a set of values allowed for an attributes.

• Cardinality

• Domain

• Tuple

• Attributes

_____ is the set of one or more attributes in a relation whch value matched with a primary key in another relation.

• candidate key

• primary key

• foreign key

• super key

_______ operator is denoted by sigma (

σ ) and it is used to find the tuples (or rows) in a relation (or table) whic

• cross

• project

• select

• join