• Question 18 Referential ____ means that if the foreign key contains a value, that value refers to an existing valid tuple( row) in another relation.
• Question 19 All primary key entries are unique, and no part of a primary key may be ____.
• Question 20 A ____ contains at least all of the attribute names and characteristics for each table in the system.
• 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 A( n) ____ is an ordered arrangement of keys and pointers.
• Question 23 In an outer join, the matched pairs would be retained and any unmatched values in the other table would be left ____.
• Question 24 ____ combines all rows from two tables, excluding duplicate rows.
• Question 25 Another word for existence-independent is ____.
• 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 A derived attribute ____.
• Question 28 Knowing the ____ number of entity occurrences is very helpful at the application software level.
• Question 29 A ____ relationship exists when three entities are associated.
• Question 30 If an entity can exist apart from one or more related entities, it is said to be ____-independent.
• Question 31 A ____ should be a derived attribute.