Category Archives: mysql

MySQL – Unique Key Table of content A Unique Key in MySQL, when applied on a certain field of a database table, does not allow duplicate values to be inserted in that column, i.e. it is used to uniquely identify a record in a table. Usually, any relational database contains a lot of information stored […]

MySQL – Union vs Join Table of content MySQL provides various relational operators to handle data that is spread across multiple tables in a relational database. Out of them, UNION and JOIN queries are fundamentally used to combine data from multiple tables. Even though they are both used for the same purpose, i.e. to combine […]

MySQL – Primary Key Table of content A PRIMARY KEY is a constraint applied on a field of a MySQL table. When this is applied, the values in that particular table column are uniquely identified. It is the most appropriate candidate key to be the main key of any table. A table can have only […]