MariaDB 表(CREATE,DROP,RENAME,ALTER)

MariaDB 表(CREATE,DROP,RENAME,ALTER)

• InnoDB is a transaction-safe engine (see Chapter 26, “Managing Transaction Processing”). It does not support full-text searching.

• MEMORY is functionally equivalent to MyISAM, but as data is stored in memory (instead of on disk) it is extremely fast (and ideally suited for temporary tables).

• MyISAM is a high-performance engine. It supports full-text searching (see Chapter 18, “Full-Text Searching”), but does not support transac- tional processing.

• ARIA (specified as ENGINE=Aria) is a new transaction-safe engine that also supports full-text searching and vital crash recovery features.

  Engine types may be mixed, so within a single database you can have different tables using different engines if required. 

CREATE表

CREATE OR REPLACE TABLE productnotes

(

  note_id    int           NOT NULL AUTO_INCREMENT,

  prod_id    char(10)      NOT NULL,

  note_date datetime       NOT NULL,

  note_text  text          NULL ,

  PRIMARY KEY(note_id),

  FULLTEXT(note_text)

) ENGINE=Aria;

CREATE TABLE orderitems

(

  order_num  int          NOT NULL ,

  order_item int          NOT NULL ,

  prod_id    char(10)     NOT NULL ,

  quantity   int          NOT NULL ,

  item_price decimal(8,2) NOT NULL ,

  PRIMARY KEY (order_num, order_item)

 

) ENGINE=Aria;

注意：每张表只有一个字段具有AUTO_INCREMENT属性,主键是能唯一区分表中所有行的属性，如果一个属性不足以区分，可以设置多个字段为主键

ALTER表

(jlive)[crashcourse]>DESC vendors;

+--------------+----------+------+-----+---------+----------------+

| Field        | Type     | Null | Key | Default | Extra          |

+--------------+----------+------+-----+---------+----------------+

| vend_id      | int(11)  | NO   | PRI | NULL    | auto_increment |

| vend_name    | char(50) | NO   |     | NULL    |                |

| vend_address | char(50) | YES  |     | NULL    |                |

| vend_city    | char(50) | YES  |     | NULL    |                |

| vend_state   | char(5)  | YES  |     | NULL    |                |

| vend_zip     | char(10) | YES  |     | NULL    |                |

| vend_country | char(50) | YES  |     | NULL    |                |

+--------------+----------+------+-----+---------+----------------+

7 rows in set (0.01 sec)

添加字段(AFTER)

(jlive)[crashcourse]>ALTER TABLE vendors ADD vend_phone CHAR(20) AFTER vend_address;

Query OK, 6 rows affected (0.01 sec)

Records: 6  Duplicates: 0  Warnings: 0

(jlive)[crashcourse]>DESC vendors;

+--------------+----------+------+-----+---------+----------------+

| Field        | Type     | Null | Key | Default | Extra          |

+--------------+----------+------+-----+---------+----------------+

| vend_id      | int(11)  | NO   | PRI | NULL    | auto_increment |

| vend_name    | char(50) | NO   |     | NULL    |                |

| vend_address | char(50) | YES  |     | NULL    |                |

| vend_phone   | char(20) | YES  |     | NULL    |                |

| vend_city    | char(50) | YES  |     | NULL    |                |

| vend_state   | char(5)  | YES  |     | NULL    |                |

| vend_zip     | char(10) | YES  |     | NULL    |                |

| vend_country | char(50) | YES  |     | NULL    |                |

+--------------+----------+------+-----+---------+----------------+

8 rows in set (0.00 sec)

删除字段

(jlive)[crashcourse]>ALTER TABLE vendors DROP COLUMN vend_phone;

Query OK, 6 rows affected (0.02 sec)

Records: 6  Duplicates: 0  Warnings: 0

添加字段(FIRST)

(jlive)[crashcourse]>ALTER TABLE vendors ADD vend_phone CHAR(20) FIRST;

Query OK, 6 rows affected (0.01 sec)

Records: 6  Duplicates: 0  Warnings: 0

(jlive)[crashcourse]>DESC vendors;

+--------------+----------+------+-----+---------+----------------+

| Field        | Type     | Null | Key | Default | Extra          |

+--------------+----------+------+-----+---------+----------------+

| vend_phone   | char(20) | YES  |     | NULL    |                |

| vend_id      | int(11)  | NO   | PRI | NULL    | auto_increment |

| vend_name    | char(50) | NO   |     | NULL    |                |

| vend_address | char(50) | YES  |     | NULL    |                |

| vend_city    | char(50) | YES  |     | NULL    |                |

| vend_state   | char(5)  | YES  |     | NULL    |                |

| vend_zip     | char(10) | YES  |     | NULL    |                |

| vend_country | char(50) | YES  |     | NULL    |                |

+--------------+----------+------+-----+---------+----------------+

 

8 rows in set (0.01 sec)

修改字段属性

(jlive)[crashcourse]>ALTER TABLE vendors MODIFY vend_phone char(250) NOT NULL;

Query OK, 6 rows affected, 6 warnings (0.02 sec)

Records: 6  Duplicates: 0  Warnings: 6

(jlive)[crashcourse]>DESC vendors;

+--------------+-----------+------+-----+---------+----------------+

| Field        | Type      | Null | Key | Default | Extra          |

+--------------+-----------+------+-----+---------+----------------+

| vend_phone   | char(250) | NO   |     | NULL    |                |

| vend_id      | int(11)   | NO   | PRI | NULL    | auto_increment |

| vend_name    | char(50)  | NO   |     | NULL    |                |

| vend_address | char(50)  | YES  |     | NULL    |                |

| vend_city    | char(50)  | YES  |     | NULL    |                |

| vend_state   | char(5)   | YES  |     | NULL    |                |

| vend_zip     | char(10)  | YES  |     | NULL    |                |

| vend_country | char(50)  | YES  |     | NULL    |                |

+--------------+-----------+------+-----+---------+----------------+

 

定义forign keys

ALTER TABLE orderitems
ADD CONSTRAINT fk_orderitems_orders FOREIGN KEY (order_num) REFERENCES orders (order_num);

ALTER TABLE orderitems
ADD CONSTRAINT fk_orderitems_products FOREIGN KEY (prod_id) REFERENCES products (prod_id);

ALTER TABLE orders
ADD CONSTRAINT fk_orders_customers FOREIGN KEY (cust_id) REFERENCES customers (cust_id);

ALTER TABLE products
ADD CONSTRAINT fk_products_vendors FOREIGN KEY (vend_id) REFERENCES vendors (vend_id);

DROP表

(jlive)[crashcourse]>SHOW TABLES;

+-----------------------+

| Tables_in_crashcourse |

+-----------------------+

| customers             |

| hello                 |

| hello_2               |

| orderitems            |

| orders                |

| productnotes          |

| products              |

| vendors               |

+-----------------------+

8 rows in set (0.00 sec)

(jlive)[crashcourse]>DROP TABLE IF EXISTS hello,hello_2;

Query OK, 0 rows affected (0.01 sec)

(jlive)[crashcourse]>SHOW TABLES;

+-----------------------+

| Tables_in_crashcourse |

+-----------------------+

| customers             |

| orderitems            |

| orders                |

| productnotes          |

| products              |

| vendors               |

+-----------------------+

6 rows in set (0.00 sec)

RENAME表

(jlive)[crashcourse]>SHOW TABLES LIKE 'hello%';

+--------------------------------+

| Tables_in_crashcourse (hello%) |

+--------------------------------+

| hello_1                        |

| hello_2                        |

| hello_3                        |

+--------------------------------+

3 rows in set (0.00 sec)

(jlive)[crashcourse]>RENAME TABLE hello_1 TO test_1, hello_2 TO test_2, hello_3 TO test_3;

Query OK, 0 rows affected (0.01 sec)

(jlive)[crashcourse]>SHOW TABLES LIKE 'test%';

+-------------------------------+

| Tables_in_crashcourse (test%) |

+-------------------------------+

| test_1                        |

| test_2                        |

| test_3                        |

+-------------------------------+

3 rows in set (0.00 sec)