數據庫之表操做

建立表

#語法：
create table 表名(
字段名1 類型[(寬度) 約束條件],
字段名2 類型[(寬度) 約束條件],
字段名3 類型[(寬度) 約束條件]
);

#注意：
1. 在同一張表中，字段名是不能相同
2. 寬度和約束條件可選
3. 字段名和類型是必須的

mysql> create database staff;
Query OK, 1 row affected (0.00 sec)

mysql> use staff;
Database changed
mysql> create table staff_info (id int,name varchar(50),age int(3),sex enum('male','female'),phone bigint(11),job varchar(11));
Query OK, 0 rows affected (0.02 sec)


mysql> show tables;
+-----------------+
| Tables_in_staff |
+-----------------+
| staff_info      |
+-----------------+
1 row in set (0.00 sec)

mysql> desc staff_info;
+-------+-----------------------+------+-----+---------+-------+
| Field | Type                  | Null | Key | Default | Extra |
+-------+-----------------------+------+-----+---------+-------+
| id    | int(11)               | YES  |     | NULL    |       |
| name  | varchar(50)           | YES  |     | NULL    |       |
| age   | int(3)                | YES  |     | NULL    |       |
| sex   | enum('male','female') | YES  |     | NULL    |       |
| phone | bigint(11)            | YES  |     | NULL    |       |
| job   | varchar(11)           | YES  |     | NULL    |       |
+-------+-----------------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

mysql> select id,name,sex from staff_info;
Empty set (0.00 sec)

mysql> select * from staff_info;
Empty set (0.00 sec)

插入數據

mysql> insert into staff_info (id,name,age,sex,phone,job) values (1,'Alex',83,'female',13651054608,'IT');
Query OK, 1 row affected (0.00 sec)

mysql> insert into staff_info values (2,'Egon',26,'male',13304320533,'Teacher');
Query OK, 1 row affected (0.00 sec)

mysql> insert into staff_info values (3,'nezha',25,'male',13332353222,'IT'),(4,'boss_jin',40,'male',13332353333,'IT');
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from staff_info;
+------+----------+------+--------+-------------+---------+
| id   | name     | age  | sex    | phone       | job     |
+------+----------+------+--------+-------------+---------+
|    1 | Alex     |   83 | female | 13651054608 | IT      |
|    2 | Egon     |   26 | male   | 13304320533 | Teacher |
|    3 | nezha    |   25 | male   | 13332353222 | IT      |
|    4 | boss_jin |   40 | male   | 13332353333 | IT      |
+------+----------+------+--------+-------------+---------+
4 rows in set (0.00 sec)

 

\c表明此行做廢

查案表結構

查看錶結構有兩種方式：

describe [tablename];這種方法和desc [tablename];效果相同；能夠查看當前的表結構

雖然desc命令能夠查看錶的定義，可是其輸出的信息還不夠全面，爲了獲得更全面的表定義信息，有時候就須要查看建立表的SQL語句，使用show create table語法。除了能夠看到表定義以外，還能夠看到engine（存儲引擎）和charset（字符集）等信息。（\G選項的含義是是的記錄可以豎向排列，以便更好的顯示內容較長的記錄。）

mysql> describe staff_info;
+-------+-----------------------+------+-----+---------+-------+
| Field | Type                  | Null | Key | Default | Extra |
+-------+-----------------------+------+-----+---------+-------+
| id    | int(11)               | YES  |     | NULL    |       |
| name  | varchar(50)           | YES  |     | NULL    |       |
| age   | int(3)                | YES  |     | NULL    |       |
| sex   | enum('male','female') | YES  |     | NULL    |       |
| phone | bigint(11)            | YES  |     | NULL    |       |
| job   | varchar(11)           | YES  |     | NULL    |       |
+-------+-----------------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

mysql> desc staff_info;
+-------+-----------------------+------+-----+---------+-------+
| Field | Type                  | Null | Key | Default | Extra |
+-------+-----------------------+------+-----+---------+-------+
| id    | int(11)               | YES  |     | NULL    |       |
| name  | varchar(50)           | YES  |     | NULL    |       |
| age   | int(3)                | YES  |     | NULL    |       |
| sex   | enum('male','female') | YES  |     | NULL    |       |
| phone | bigint(11)            | YES  |     | NULL    |       |
| job   | varchar(11)           | YES  |     | NULL    |       |
+-------+-----------------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

mysql> show create table staff_info\G;
*************************** 1. row ***************************
       Table: staff_info
Create Table: CREATE TABLE `staff_info` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(50) DEFAULT NULL,
  `age` int(3) DEFAULT NULL,
  `sex` enum('male','female') DEFAULT NULL,
  `phone` bigint(11) DEFAULT NULL,
  `job` varchar(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.01 sec)

ERROR: 
No query specified