what is Constraint? How many types of constraints in SQL ?
Answer Posted / pandia rajan
A constraint is a property assigned to a column or the set
of columns in a table that prevents certain types of
inconsistent data values from being placed in the column
(s). Constraints are used to enforce the data integrity.
This ensures the accuracy and reliability of the data in
the database
CONSTRAINT=The threat or use of force to prevent, restrict,
or dictate the action or thought of others.
there are 7 types of constraints are there and they are
grouped in to 4 types. They are
TYPES GROUP
1.DEFAULT = DOMAIN INTEGRITY
2.NOT NULL = DOMAIN INTEGRITY
3.CHECK = DOMAIN INTEGRITY
4.FOREIGN KEY = REFERENTIAL INTEGRITY
5.UNIQUE KEY = ENTITY INTEGRITY
6.PRIMARY KEY = DOMAIN INTEGRITY
7.RULE = USER DEFINED INTEGRITY
| Is This Answer Correct ? | 8 Yes | 10 No |
Post New Answer View All Answers
How do database indexes work?
What are data resources?
What is dirty read?
How can you check the version of sql server?
Explain Capacity planning to create a database? and how to monitor it?
‘Order by’ is not allowed in a view how can you sort information from a view?
What action plan is preferred if sql server is not responding?
What is SQL Azure Firewall?
What are approximate numeric data types in ms sql server?
What is a benefit of using an after insert trigger over using a before insert trigger?
What are the benefits of filtered indexes?
What are alternate keys?
What are the advantages of using cte?
How can you find out if the current user is a member of the specified microsoft® windows nt® group or microsoft sql server™ role?
What is the contrast between sql and mysql?