Mysql Interview Question and Answers

45. What Storage Engines do you use in MySQL?
  Storage engines used to be called table types.
Data in MySQL is stored in files (or memory) using a variety of different techniques. Each of these techniques employs different storage mechanisms, indexing facilities, locking levels and ultimately provides a range of different functions and capabilities. By choosing a different technique you can gain additional speed or functionality benefits that will improve the overall functionality of your application.
46. Where MyISAM table is stored?
 
    Each MyISAM table is stored on disk in three files.
  • The ‘.frm’ file stores the table definition.
  • The data file has a ‘.MYD’ (MYData) extension.
  • The index file has a ‘.MYI’ (MYIndex) extension
47. Define Primary key?
  MYSQL allows only one primary key. A primary key is used to uniquely identify each row in a table. It can either be part of the actual record itself.A primary key can consist of one or more fields on a table. When multiple fields are used as a primary key, they are called a composite key.
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