:: Home Page
 Advertise your Business Here     
Browse  |   Placement Papers  |   Company  |   Code Snippets  |   Certifications  |   Visa Questions
Post Question  |   Post Answer  |   My Panel  |   Search  |   Articles  |   Topics  |   Errors
   Testimonials Refer this Site  Refer This Site to Your Friends  Site Map  Contact Us      
Categories >> Software >> Databases >> MySQL


Question What is the difference between primary and unique key
 Question Asked In Companies :: CSC,     < I also faced this Question! >
 Question Submitted By :: kamaltimalsina012
  Answer Posted By  
Primay key restrict the duplicacy in the records and does
not accept null value or there are only one primary key in
a table

Unique constraint also restict the duplicacy but it accept
the null value one or more then one. We can apply unique
constraint more than one column

Is This Answer Correct ?    2 Yes 2 No

  ashish asthana
View All Answers
Please Help Members By Posting Answers For Below Questions
 Question Views   Select
How to enable or disable a row of a table using MySQL in struts? 1870
In a property booking section want a query to check that property is booked from StartDate to EndDate.Booking Table field are given id proerty_id start_date checkout_date no_of_visitor booking date status Waiting yours answer.. Thanks In Advance... 1080
1)for snapshot replication which agents used? 2)for Transcation replication which agents used? 3)for merge replciation which agents used? 607
How internally data stores in MyISAM and INNODB table types? 872
what is mysql optimization in brief? 782
Can u give the example by taking an unnormalized table and make that 1nf and then 25nf, and then 3 nf? 2813
why not null is not allowed at table level 816
suppose data is copie to oracle to sql by using DTS. Actully it taken 2 hours. suppose some day distribute the server in the middle of 2 hours. after how can i get the data ? 615
how to get only updated, deleted , inserted records after certain interval time in mysql with out using triggers... 669
What is striped backup 698
What is difference between Sql server and MySql database? It may be silly question but i really dont know. 230
Table - Products has number of products as below Productid ProductName 1 iPhone 2 iPad 3 BlackBerry Table - SalesPersonProduct has the below records Salespersonid productid S1 1 S1 2 S1 3 S2 1 S3 2 Write a SQL query that returns the total number of sold products 1107
What are the critical issues you have resolved in your company 603
What are the method you will follow while sql installing 819
i made a table whih contain a column "Photo" with image data type and i want to insert the byte of a picture present in my hardisk using insert statement in that colum... so what will be my insert statement? 1090
E-Mail New Answers        Answer Selected Questions