Database 與 Tables
Database有多的Tables
Tables是存取數據的地方，有一定的結構
Database Level
- show databases
- create database
- drop database
- use database
- select database
- 啟動MySQL
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| sudo /usr/local/mysql/support-files/mysql.server start
使用系統密碼
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- 連接 MySQL 伺服器與 MySQL 用戶端
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| /usr/local/mysql/bin/mysql -u root -h 127.0.0.1 -p
密碼
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show databases 展示所有Db
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| show databases;
SHOW databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
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information_schema,mysql,performance_schema,sys 為默認
create database 創建Db
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| create database test_db;
Query OK, 1 row affected (0.00 sec)
//result
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test_db |
+--------------------+
5 rows in set (0.00 sec)
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資料庫內多了一個剛剛創建的test_db
use test_db
默認並沒使用任何Database
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| use test_db;
Database changed
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select database()
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| select database();
+------------+
| database() |
+------------+
| test_db |
+------------+
1 row in set (0.00 sec)
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如果沒有被 use => select database()
默認並沒使用任何Database 為NULL
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| +------------+
| database() |
+------------+
| NULL |
+------------+
1 row in set (0.00 sec)
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drop database 刪除數據庫名稱
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| drop database test_db;
Query OK, 0 rows affected (0.02 sec)
//result
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.00 sec)
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分號在MySql :結束應該去執行＝>可改變的
Delay
修改不使用分號改為$$
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| delimiter $$
show databases $$;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.01 sec)
delimiter ;
當前有效
show databases $$;
show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
4 rows in set (0.01 sec)
|
使用KeyWord大寫