SQL also allows users to build constraints onto tables or columns to restrict the type of data they contain. Database IndexingĬREATE INDEX and DROP INDEX statements are used to create and delete indexes in tables. GRANT and/or REVOKE user privileges, etc. SELECT, INSERT, UPDATE, DELETE of records within tables. This includes CREATE (tables, views, objects, etc.), ALTER and DROP (delete). Four Categories of SQL Commands Data Definition Language (DDL) This makes it very easy for someone with a basic knowledge of SQL to work in many different environments and perform a wide variety of tasks.
#Sql principal definition update#
While different iterations of SQL may utilize different syntax for key operations, in general, basic commands like select, insert, update and create are common to all SQL releases. In fact, many non-relational databases like MongoDB and DynamoBD are called NoSQL products due to their lack of SQL programming. SQL has remained a consistently popular choice for database users over the years primarily due to its ease of use and the highly effective manner in which it queries, manipulates, aggregates data and performs a wide range of other functions to turn massive collections of structured data into usable information.įor this reason, it has been incorporated into numerous commercial database products, such as MySQL, Oracle, Sybase, SQL Server, Postgres and others. Techopedia Explains Structured Query Language (SQL)
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