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Author: Selim Ahmed

Thank you for visiting my personal blog. I’m Selim Ahmed, a tech-savvy who loves to learn a new technology every day. Innovation, research, and development is my daily activities. I love to work in a place where I can learn, innovate, and develop new things.Please feel free to reach me on any comments and feedback you have. I would be more than glad to listen and reply.

What is difference between Primary Key and Unique Key

Posted on by Selim Ahmed

Primary key and Unique key are two important concept in relational database, and used to uniquely identify a row in a table. Both primary key and unique key can identify a row uniquely but there are some subtle difference between them which we will see in this article. In fact primary key vs unique is a popular SQL interview questions along with classics like truncate vs delete and How to manage transaction in database, mostly asked to fresher and 2 to 3 years experience guys in any programming language. SQL is not just limited to any DBA or PLSQL developer but its an important skill even for Java programmer and you can expect SQL interview question even in many Java interviews. Some time programmer also confuse between foreign key and unique key, which is primary key of other table in relation.

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