what is primary key,unique key, foreign key? can u teach me
in simple language?
- 44 Answers
- 180971 Views
- Banking, CMC, CTS, HCL, Infosys, Keggfarms, SkyEss, Sunrise, TCS, Web Synergies, Wipro, I also Faced
- E-Mail Answers
Answer Posted / kranthi
primary key: primary creates a clustered index on the
column and it doesn't allow null values.
unique key: unique key creates non clustered index by
default.it allows "one null value".
foreign key: A foreign key (FK) is a column or combination
of columns used to establish and enforce a link between the
data in two tables
| Is This Answer Correct ? | 212 Yes | 76 No |
Post New Answer View All Answers
What is a Database?
Give the syntax of exception handling used in DBMS?
What is the best database?
Differentiate between unique key and foreign key?
What is dialect in database?
Design an ETL process( batch job/script)from source to starting that u will not be dependent on the source in the near future?please elobarate details on what are things to consider.if you'd like to do a diagram that will be great.please answer it
please tell me the informatica telecom projects interview question? like if they ask about project explanation and the difficulties and the solutions taken to solve the issues for telecom projects,e.g i am workin for a vodafone project handlin postpaid section,pls tell me wat wud be the process if i work in this ? thanks
What is the difference between primary key, foreign key and candidate key?
What is odm database?
How many types of locks are present in a database?
HOW PASS PARAMETERS FOLLOWING ORDER RPG-CL-RPG?
What is the difference between database and server?
Is redis in memory database?
Given a table Employee which has columns name and salary, write an SQL query to find the employee with the second highest salary.
Can a database table exist without a primary key?
