mysql 获取 库 和 表 的信息

/*显示 数据库系统 中 有哪些数据库*/
mysql> show databases;

+----------+
| Database |
+----------+
| mysql    |
| test     |
| tmp      |
+----------+

/*创建数据库*/
mysql> CREATE DATABASE menagerie;


/*选择一个数据库*/
mysql> USE test
Database changed

/*显示数据库中有哪些表*/
mysql> show tables;

/*创建表 pet, 包含字段及其类型 */
mysql> CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20),
       species VARCHAR(20), sex CHAR(1), birth DATE, death DATE);

/*查看表结构*/
mysql> DESCRIBE pet;
+---------+-------------+------+-----+---------+-------+
| Field   | Type        | Null | Key | Default | Extra |
+---------+-------------+------+-----+---------+-------+
| name    | varchar(20) | YES  |     | NULL    |       |
| owner   | varchar(20) | YES  |     | NULL    |       |
| species | varchar(20) | YES  |     | NULL    |       |
| sex     | char(1)     | YES  |     | NULL    |       |
| birth   | date        | YES  |     | NULL    |       |
| death   | date        | YES  |     | NULL    |       |
+---------+-------------+------+-----+---------+-------+

/*查看当前处于哪个数据库*/
mysql> SELECT DATABASE();
+------------+
| DATABASE() |
+------------+
| menagerie  |
+------------+

/*查看索引信息*/
mysql> SHOW INDEX FROM tbl_name;