!ntegrity and ACID (1.3.2 e/f)

Question 1

Referential integrity requires…

Answer 1

that if a foreign key is added to a table and a value is entered into a foreign may field the value must exist in the primary key field of another table

Question 2

Referential integrity foreign key can be..

Answer 2

null to signify that there is no relationship
if null values are not allowed then there must be related record

Question 3

What is data integrity?

Answer 3

refers to maintaining and ensuring the reliability of data in terms of its accuracy completeness and consistency over its life cycle

Question 4

What is referential integrity?

Answer 4

refers to the accuracy and consistency of data within a relationship

Question 5

Data integrity

Answer 5

about ensuring that data is guaranteed to be correct
entity integrity
domain integrity

Question 6

What is entity integrity?

Answer 6

stipulates that every table must ave a primary key
the primary key for every record of a table must have a unique value and can not be null

Question 7

What is domain integrity?

Answer 7

means that every attribute in a relational database is associated with a domain

Question 8

Maintaining integrity - cascade delete

Answer 8

use cascade delete when removing a record from a database
ensures that if a record is removed from a table all references to that record are removed from every other table as well

Question 9

Maintaining integrity - record locking

Answer 9

prevents other users from making changes to a record while you are editing it
prevents data being lost or immediately overridden by accident
can cause deadlock which can be solved by deleting a transaction to clear it