Integrity constraints means..? how many and what are they?
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Answer / firoz basha
Integrity constraint:- An IC is one which does not allow
invalid data entry into the database.
there are 3 types of Integrity constraints:
1. Entity Integrity COnstraint
primary key
unique key
Primary key does not allow null values and duplicate
values
unique key does not allow duplicate values.
unique key allows any number of null values (in case
of oracle)
unikey key allows only one null value. i.e, single null
value ( in the case of sql server 2000)
2. Domain Integrity Constraint
not null constraint
check constraint
rule constraint (in case of SQL SERVER 2000)
rule is an alternate to check constraint
3. Referential Integrity constraint
foreign key constraint
Is This Answer Correct ? | 34 Yes | 1 No |
Integrity constraints provide a way of ensuring that
changes made to the database by authorized users do not
result in a loss of data consistency.
An integrity constraint can be any arbitrary predicate
applied to the database.
They may be costly to evaluate, so we will only consider
integrity constraints that can be tested with minimal
overhead.
Types of integrity constraints
(1) Non-null
(2) Key
(3) Referential integrity
(4) Attribute-based
(5) Tuple-based
(6) General assertions
plzz let me know if it's wrong
Is This Answer Correct ? | 18 Yes | 9 No |
Answer / sriram s
Domain integrity enforces valid entries for a given column
by restricting the type , the format or the range of
possible values
Is This Answer Correct ? | 6 Yes | 0 No |
Domain Integrity Constraint
//not null constraint this is not come
check constraint
//rule constraint (in case of SQL SERVER 2000)
//rule is an alternate to check constraint
only check because it is used as whole domain while all are
in row or tuple !
Is This Answer Correct ? | 4 Yes | 0 No |
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