Database languages are divided into four categories: 1. Data query language DQL; 2. Data manipulation language DML; 3. Data definition language DDL; 4. Data control language DCL.
The operating environment of this tutorial: windows7 system, mysql8 version, Dell G3 computer.
SQL language is divided into four categories: data query language DQL, data manipulation language DML, data definition language DDL, and data control language DCL.
The basic structure of data query language DQL is a query block composed of SELECT clause, FROM clause, and WHERE
clause :
SELECT 64045639064cb073852c1417fd64f6b2
##FROM 0cdbed13dfb43a6d12d1ba3a3c9ad85f
WHERE 2bce67c46a87998283576015cd7b1478
CREATE TABLE/VIEW/INDEX/SYN/CLUSTERTable view index synonym clusterDDL operations are submitted implicitly! Cannot rollback4. Data control language DCLData control language DCL is used to grant or revoke certain privileges to access the database, and control the time and effect of database manipulation transactions, and perform operations on the database. Surveillance etc. Such as:
1) GRANT: Authorization.
SQL>ROLLBACK;
(1) Explicit submission
The submission completed directly using the COMMIT command is an explicit submission. The format is:SQL>COMMIT;
(2) Implicit submissionThe submission completed indirectly using SQL commands is implicit. submission. These commands are:
(3) Automatic submission
若把AUTOCOMMIT设置为ON,则在插入、修改、删除语句执行后, 系统将自动进行提交,这就是自动提交。其格式为: SQL>SET AUTOCOMMIT ON;(Recommended tutorial:
mysql video tutorial)
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