• Question 18 Any attribute that is part of a key is known as a ____.
• Question 19 ____ combines all rows from two tables, excluding duplicate rows.
• Question 20 A( n) ____ is perceived as a two-dimensional structure composed of rows and columns.
• Question 21 In the context of a database table, the statement ― A ____ B ‖ indicates that if you know the value of attribute A, you can look up the value of attribute B.
• Question 22 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.
• Question 23 A( n) ____ join only returns matched records from the tables that are being joined.
• Question 24 In an outer join, the matched pairs would be retained and any unmatched values in the other table would be left ____.
• Question 25 A ____ identifier is composed of more than one attribute.
• Question 26 An entity is said to be ____-dependent if it can exist in the database only when it is associated with another related entity occurrence.
• Question 27 Another word for existence-independent is ____.
• Question 28 A ____ relationship exists when an association is maintained within a single entity.
• Question 29 Knowing the ____ number of entity occurrences is very helpful at the application software level.
• Question 30 A ____ relationship exists when three entities are associated.