What are various constraints used in SQL?



What are various constraints used in SQL?..

Answer / rajshri.20

SQL constraints are used to specify rules for the data in a table.

NOT NULL - Indicates that a column cannot store NULL value
UNIQUE - Ensures that each row for a column must have a unique value
PRIMARY KEY - A combination of a NOT NULL and UNIQUE. Ensures that a column (or combination of two or more columns) have an unique identity which helps to find a particular record in a table more easily and quickly
FOREIGN KEY - Ensure the referential integrity of the data in one table to match values in another table
CHECK - Ensures that the value in a column meets a specific condition
DEFAULT - Specifies a default value when specified none for this column

Is This Answer Correct ?    2 Yes 0 No

Post New Answer

More Oracle General Interview Questions

12. Display the client name in upper case only and in lower case only.

1 Answers   Wipro,


you are a universe designer and report developer in BO, what type of information you gather from client?Briefly explain plz

0 Answers   iFlex,


How would you extract DDL of a table without using a GUI tool?

1 Answers  


Difference between cartesian join and cross join?

0 Answers  


How to run create database statement again?

0 Answers  


Will the Optimizer always use COST-based approach if OPTIMIZER_MODE is set to "Cost"?

1 Answers  


What are named parameters?

0 Answers  


What is the CAP theorem?

1 Answers  


In oracle there is column command, how will you explain that?

0 Answers   Aricent,


How to shutdown your 10g xe server?

0 Answers  


How do I recompile a procedure in oracle?

0 Answers  


Explain the use of parfile option in exp command.

0 Answers  


Categories
  • Oracle General Interview Questions Oracle General (1808)
  • Oracle DBA (Database Administration) Interview Questions Oracle DBA (Database Administration) (261)
  • Oracle Call Interface (OCI) Interview Questions Oracle Call Interface (OCI) (10)
  • Oracle Architecture Interview Questions Oracle Architecture (90)
  • Oracle Security Interview Questions Oracle Security (38)
  • Oracle Forms Reports Interview Questions Oracle Forms Reports (510)
  • Oracle Data Integrator (ODI) Interview Questions Oracle Data Integrator (ODI) (120)
  • Oracle ETL Interview Questions Oracle ETL (15)
  • Oracle RAC Interview Questions Oracle RAC (93)
  • Oracle D2K Interview Questions Oracle D2K (72)
  • Oracle AllOther Interview Questions Oracle AllOther (241)