一天一点点(20151216）

主题: MySQL Client Programs
（来自MySQL reference manual 4.5.1.4）
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4.5.1.3 mysql Logging
4.5.1.4 mysql Server-Side Help
mysql>help me
4.5.1.5 Executing SQL Statements from a Text File
shell> mysql db_name
shell> mysql db_name < text_file
shell> mysql < text_file
mysql> source file_name
mysql> \. file_name
--verbose选项
--default-character-set=utf8
4.5.1.6 mysql Tips
4.5.1.6.1 Input-Line Editing
1.普通技能
left-arrow and right-arrow keys move horizontally within the current input line--行编辑；
up-arror and down-arrow keys move up and down--历史命令查询；
Backspace、Enter
2.高级技巧
Documentation for the libedit and readline libraries is available online
ctrl+w和ctrl+u
编辑.editrc文件
bind "^W" ed-delete-prev-word
bind "^U" vi-kill-line-prev
4.5.1.6.4 Using the --safe-updates Option
SET sql_safe_updates=1, sql_select_limit=1000, max_join_size=1000000;
mysql> desc safe_test1;
+-------+---------------------+------+-----+---------+-------+
| Field | Type                | Null | Key | Default | Extra |
+-------+---------------------+------+-----+---------+-------+
| id    | bigint(20) unsigned | NO   |     | 0       |       |
| ename | varchar(20)         | YES  |     | NULL    |       |
+-------+---------------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql> desc safe_test;
+-------+---------------------+------+-----+---------+----------------+
| Field | Type                | Null | Key | Default | Extra          |
+-------+---------------------+------+-----+---------+----------------+
| id    | bigint(20) unsigned | NO   | PRI | NULL    | auto_increment |
| ename | varchar(20)         | YES  |     | NULL    |                |
+-------+---------------------+------+-----+---------+----------------+

UPDATE tbl_name SET not_key_column=val WHERE key_column=val;
UPDATE tbl_name SET not_key_column=val LIMIT 1;

delete操作比较
前提:safe_test有索引safe_test1无索引
1.无where条件的delete，均不能执行
mysql> delete from safe_test;
ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
mysql> delete from safe_test1;
ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
2.有where条件，safe_test使用索引列为条件，能执行；safe_test1不能执行
mysql> delete from safe_test1 where id=4;
ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
mysql> delete from safe_test where id=4;
Query OK, 1 row affected (0.05 sec)
3.safe_test使用非索引列为条件，不能执行
mysql> delete from safe_test where ename='sad';
ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column

update操作与delete操作雷同

4.5.1.6.5 Disabling mysql Auto-Reconnect
客户端的自动重新连接可能会造成一些严重的问题，因为重连前后可能有些数据依赖关系不在是实际期望的那样，有可能会造成误操作，所以建议禁掉这一行为 使用--skip-reconnect选项