MySQL SQLLesson 4Free preview

MySQL SQL

This lesson is part of MySQL · All levels

Summary

SQL is the standard language for managing relational databases, and MySQL uses it with a number of customizations of its own. SQL commands can be grouped by function: DDL for table structure, DML for data manipulation, and DQL for data reading. Understanding this grouping makes it easier to predict the impact of a command, especially that of changing data.

Key points

SQL is a declarative language: we state what data is desired, not the steps of processing it.
DDL (Data Definition Language) contains CREATE, ALTER, and DROP to change the structure of the table
DML (Data Manipulation Language) contains INSERT, UPDATE, and DELETE to change the contents of the table
DQLs contain SELECTs to read data, while TCLs like COMMIT and ROLLBACK manage transactions

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