Database Structure Database Connection table

Database structure:

Ddl:

libraries, tables, indexes, fields, views, triggers, stored procedure database users

Dml:

CRUD additions and deletions change

DCL:

User Rights Management

DESCRIBE

Having: Re-filtering on the basis of statistics, the condition field allows the name of a statistic field that does not exist in the table

1. Database Connection Table

Left Join

Right Join

INNER JOIN

2. Database engine (System resources, data security, concurrency)

MyISAM

InnoDB

Lock

Transaction

3. Database optimization

Index: Single index, combined index (index is space-occupying)

Sql:1, use with caution

Database Structure Database Connection table