An index can be used to…….
a) improve the performance
b) structure of database
c) reduce data dependency
d) all of these
Which of the following are properties of relations?
a) each attribute unique name
b) no two rows in relation
c) no multivalued attributes
d) all of these
Which of the following is a key?
a) identified only one record
b) most important field in record
c) first field of table
d) none of these
Which of the following describe the primary key?
a) it must unique
b) helps in indexing of large database
c) makes sorting quicker
d) all of these
Which of the following is not a good primary key?
a) social security number
b) order number
c) zip code
d) student id number
How many primary keys can a table have?
a) one
b) at least one
c) between 1 and 5
d) no limit
