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马哥 33_01 _MySQL系列之五——MySQL数据类型及sql模型 有大用
存储引擎(表类型) 这两种是通用场景
MyISAM表: 无事务,它是表锁
.frm ( format )表结构定义文件
.MYD (mysql data)表数据 (D data)
.MYI (mysql index)索引 (I index)
InnoDB表: 事务,它是行锁
.frm ( format ) 表结构
.ibd ( format ) 表空间 (数据和索引) (i index) (b table? 还是base?) (d data)(假如每表一个单独的表空间的话,否则所有表共用它)
Mysql: 初始化后名叫mysql数据库->MyISAM
>show engines 查看所有引擎
>show table status [ like ... ] 查看表的状态属性
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine (引擎) | Support (是否支持)| Comment(简要描述) | Transactions(事务) | XA (分布式事务) | Savepoints (保存点) |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| MRG_MYISAM | YES | Collection of identical MyISAM tables | NO | NO | NO |
| PERFORMANCE_SCHEMA | YES | Performance Schema | NO | NO | NO |
| MyISAM | YES | MyISAM storage engine | NO | NO | NO |
| BLACKHOLE | YES | /dev/null storage engine (anything you write to it disappears) | NO | NO | NO |
| CSV | YES | CSV storage engine | NO | NO | NO |
| InnoDB | DEFAULT (默认存储引擎)| Supports transactions, row-level locking, and foreign keys | YES | YES | YES |
| ARCHIVE | YES | Archive storage engine | NO | NO | NO |
| MEMORY | YES | Hash based, stored in memory, useful for temporary tables | NO | NO | NO |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
8 rows in set (0.00 sec)
# 可以在事务中,有多个保存到,可以回滚到不同的保存点 (所以一般支持事务才支持保存点)
mysql>
mysql> use mysql
Database changed
mysql> show tables;
+---------------------------+
| Tables_in_mysql |
+---------------------------+
| columns_priv |
| db |
| event |
| func |
| general_log |
| help_category |
| help_keyword |
| help_relation |
| help_topic |
| host |
| ndb_binlog_index |
| plugin |
| proc |
| procs_priv |
| proxies_priv |
| servers |
| slow_log |
| tables_priv |
| time_zone |
| time_zone_leap_second |
| time_zone_name |
| time_zone_transition |
| time_zone_transition_type |
| user |
+---------------------------+
24 rows in set (0.00 sec)
mysql>
mysql> help show table status # help + command ( help 加 命令)
Name: 'SHOW TABLE STATUS'
Description:
Syntax:
SHOW TABLE STATUS [{FROM | IN} db_name]
[LIKE 'pattern' | WHERE expr]
SHOW TABLE STATUS works likes SHOW TABLES, but provides a lot of
information about each non-TEMPORARY table. You can also get this list
using the mysqlshow --status db_name command. The LIKE clause, if
present, indicates which table names to match. The WHERE clause can be
given to select rows using more general conditions, as discussed in
http://dev.mysql.com/doc/refman/5.5/en/extended-show.html.
URL: http://dev.mysql.com/doc/refman/5.5/en/show-table-status.html
mysql> select database();
+------------+
| database() |
+------------+
| mysql |
+------------+
1 row in set (0.00 sec)
mysql>
mysql> show table status like 'user'\G # 查看表的属性信息
*************************** 1. row ***************************
Name: user
Engine: MyISAM
Version: 10
Row_format: Dynamic
Rows: 3
Avg_row_length: 126
Data_length: 380
Max_data_length: 281474976710655
Index_length: 2048
Data_free: 0
Auto_increment: NULL
Create_time: 2020-09-15 12:58:20
Update_time: 2020-09-15 14:44:54
Check_time: NULL
Collation: utf8_bin
Checksum: NULL
Create_options:
Comment: Users and global privileges
1 row in set (0.00 sec)
mysql>
程序语言连接数据库的方式:
动态sql:通过函数或方法与数据库服务器建立连接,将sql发往数据库服务器
嵌入式sql:使用程序开发语言本身的格式来写的查询语句,通过api直接连到服务器上,(连之前要进行编译的)
JDBC, java database Connectivity:java数据库互连
ODBC,open database Connectivity: 开放数据库互连
客户端工具: mysql,mysqladmin.mysqldump,mysqlimport,mysqlcheck
服务器端工具: mysqld,mysqld_safe(支持安全线程的),mysql_multi(支持多实例,一个物理服务器上可以运行多个mysql进程,但端口不同)
[root@mail ~]# ls /usr/local/mysql/bin/
innochecksum mysql_client_test mysql_setpermission
msql2mysql mysql_config mysqlshow
myisamchk mysql_convert_table_format mysqlslap
myisam_ftdump mysqld mysqltest
myisamlog mysqld_multi mysql_tzinfo_to_sql
myisampack mysqld_safe(启动mysql服务器用的是它,而不是mysqld) mysql_upgrade
my_print_defaults mysqldump mysql_waitpid
mysql mysqldumpslow mysql_zap
mysqlaccess mysql_find_rows perror
mysqlaccess.conf mysql_fix_extensions replace
mysqladmin mysqlhotcopy(mysql的一个备份的工具) resolveip
mysqlbinlog (非客户端工具,用得比较多,查看mysql二进制日志) mysqlimport resolve_stack_dump
mysqlbug mysql_plugin
mysqlcheck mysql_secure_installation
[root@mail ~]#
[root@mail ~]# vim /etc/init.d/mysqld
[root@mail ~]# man mysqld_safe
my.cnf 配置文件
unix上
/etc/my.cnf-->/etc/mysql/my.cnf-->$MYSQL_HOME/my.cnf--> --default-extra-file=/path/to/file-> ~/.my.cnf
[mysqld]
[mysqld_safe]
[client] #对所有客户端生效
host =
[mysql] #只对mysql这一个客户端生效
绝大多数配置的参数都可以在命令行直接指定的
比如 mysql --host 可以在配置文件中指 (配置文件中不要加 -- 杠杠了)
杠杠 可以为下短横或中短横,但建议统一格式
default-extra-file
default_extra_file
innodb_file_per_table
innodb-file-per-table
[root@mail ~]# mysqld --help --verbose # 查看 mysqld 能支持的选项配置,各种指令相关信息
跟 mysql > show variables ; 显示的内容近似,
mysql 装好了,启动不了,什么没有更新pid文件这些情况
原因可能有:
1) 此前装的mysql 忘了关掉了
# killall mysqld (killall mysqld_safe) 或者找到进程,并杀死这个进程,让其释放3306端口
datadir = /mydata/data 数据目录下,会产生 hostname.err 错误日志文件(启动之后的错误信息都在里面) 如果没有hostname.err文件,说明数据目录位置指错了,此时要 编辑主配置文件 my.cnf 指定 datadir 的位置
2) 数据初始化失败
3) 数据目录位置错误
4) 数据目录权限问题
5) mysql运行目录权限问题
排查问题:实在不行初始化数据库,再找找主配置文件,把 datadir指向数据目录,再启动,一般就可以了
DBA: (database admistrator)
开发DBA: 数据库设计,SQL语句,存储过程,存储函数,触发器,水晶报表的开发(Oracle上)
管理DBA: 安装,升级,备份,恢复,用户管理,权限管理,监控,性能分析,基准测试
Developing With MySQL
MySQL data types: mysql 数据类型
MySQL Language Structure: mysql结构化查询语言的使用
数据类型:
数值型: 不要指定长度?
精确数值
int
decimal
近似数值
float
double
real (有时相当于float ,有时相当于double,根据系统而定,用得不多)
字符型: 字符型必须要指定长度的
定长字符型: CHAR(不区分大小写),BINARY(区分大小写)
变长字符型: VARCHAR(不区分大小写),VARBINARY(区分大小写)
长字符:text(相当于CHAR,不区分大小写),blob(相当于 binary large object , 区分大小写)
ENUM
SET
日期时间型
date,time,datetime,timestamp
域(field 字段)属性,修饰符: 定义域限制的
SQL:
数据类型的作用:
1)它表示哪种类型的数据
2)它表示最大的存储空间 (char(3)只能存3个字符)
3)定长,变成它就己经确定了
4)如何比较及排序字符,(区不区分大小写也在这里定义了)
5)这个类型是否能够被创建索引
> show character set; #用于显示当前服务器所支持的所有字符集
> show collation; #显示排序规则的
> show global variables; #显示全局变量
mysql遵循sql03的标准
数值型
数值型
bit 按位存储的用的不多
float: 4个字节存储
double:8个字节存储
字符串型
SET: 给你几个字符,组成任意值
ENUM 枚举,里面各项选一个
SET 集合,,里面的各项的组合
日期时间类型
text 上面创建索引,一般不能索引整个字段的,在char可以索引整个字段的
所以不能随意变换数据类型
越简单的数据类型,管理起来成本越低
字符串类型的修饰属性:
NOT NULL
NULL
DEFAULT
BINARY : 是不是区分大小写的,好像现在不用 BINARY 修饰符了
CHARACTER SET : 字符集 (字符类型的) (默认从表继承)
COLLATION : 排序规则 (字符类型的) (默认从表继承)
字符规则如未指定,,从字段,表,数据库,服务器一层一层的继承
看 mysql 支持哪些字符集规则
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 17
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show character set;
+----------+-----------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+-----------------------------+---------------------+--------+
| big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 |
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| ujis | EUC-JP Japanese | ujis_japanese_ci | 3 |
| sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| tis620 | TIS620 Thai | tis620_thai_ci | 1 |
| euckr | EUC-KR Korean | euckr_korean_ci | 2 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| utf16 | UTF-16 Unicode | utf16_general_ci | 4 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| utf32 | UTF-32 Unicode | utf32_general_ci | 4 |
| binary | Binary pseudo charset | binary | 1 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
| cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 |
| eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 |
+----------+-----------------------------+---------------------+--------+
39 rows in set (0.00 sec)
mysql>
mysql> show collation;
+--------------------------+----------+-----+---------+----------+---------+
| Collation | Charset | Id | Default | Compiled | Sortlen |
+--------------------------+----------+-----+---------+----------+---------+
| big5_chinese_ci | big5 | 1 | Yes | Yes | 1 |
| big5_bin | big5 | 84 | | Yes | 1 |
| dec8_swedish_ci | dec8 | 3 | Yes | Yes | 1 |
| dec8_bin | dec8 | 69 | | Yes | 1 |
| cp850_general_ci | cp850 | 4 | Yes | Yes | 1 |
| cp850_bin | cp850 | 80 | | Yes | 1 |
| hp8_english_ci | hp8 | 6 | Yes | Yes | 1 |
| hp8_bin | hp8 | 72 | | Yes | 1 |
| koi8r_general_ci | koi8r | 7 | Yes | Yes | 1 |
| koi8r_bin | koi8r | 74 | | Yes | 1 |
| latin1_german1_ci | latin1 | 5 | | Yes | 1 |
| latin1_swedish_ci | latin1 | 8 | Yes | Yes | 1 |
| latin1_danish_ci | latin1 | 15 | | Yes | 1 |
| latin1_german2_ci | latin1 | 31 | | Yes | 2 |
| latin1_bin | latin1 | 47 | | Yes | 1 |
| latin1_general_ci | latin1 | 48 | | Yes | 1 |
| latin1_general_cs | latin1 | 49 | | Yes | 1 |
| latin1_spanish_ci | latin1 | 94 | | Yes | 1 |
| latin2_czech_cs | latin2 | 2 | | Yes | 4 |
| latin2_general_ci | latin2 | 9 | Yes | Yes | 1 |
| latin2_hungarian_ci | latin2 | 21 | | Yes | 1 |
| latin2_croatian_ci | latin2 | 27 | | Yes | 1 |
| latin2_bin | latin2 | 77 | | Yes | 1 |
| swe7_swedish_ci | swe7 | 10 | Yes | Yes | 1 |
| swe7_bin | swe7 | 82 | | Yes | 1 |
| ascii_general_ci | ascii | 11 | Yes | Yes | 1 |
| ascii_bin | ascii | 65 | | Yes | 1 |
| ujis_japanese_ci | ujis | 12 | Yes | Yes | 1 |
| ujis_bin | ujis | 91 | | Yes | 1 |
| sjis_japanese_ci | sjis | 13 | Yes | Yes | 1 |
| sjis_bin | sjis | 88 | | Yes | 1 |
| hebrew_general_ci | hebrew | 16 | Yes | Yes | 1 |
| hebrew_bin | hebrew | 71 | | Yes | 1 |
| tis620_thai_ci | tis620 | 18 | Yes | Yes | 4 |
| tis620_bin | tis620 | 89 | | Yes | 1 |
| euckr_korean_ci | euckr | 19 | Yes | Yes | 1 |
| euckr_bin | euckr | 85 | | Yes | 1 |
| koi8u_general_ci | koi8u | 22 | Yes | Yes | 1 |
| koi8u_bin | koi8u | 75 | | Yes | 1 |
| gb2312_chinese_ci | gb2312 | 24 | Yes | Yes | 1 |
| gb2312_bin | gb2312 | 86 | | Yes | 1 |
| greek_general_ci | greek | 25 | Yes | Yes | 1 |
| greek_bin | greek | 70 | | Yes | 1 |
| cp1250_general_ci | cp1250 | 26 | Yes | Yes | 1 |
| cp1250_czech_cs | cp1250 | 34 | | Yes | 2 |
| cp1250_croatian_ci | cp1250 | 44 | | Yes | 1 |
| cp1250_bin | cp1250 | 66 | | Yes | 1 |
| cp1250_polish_ci | cp1250 | 99 | | Yes | 1 |
| gbk_chinese_ci | gbk | 28 | Yes | Yes | 1 |
| gbk_bin | gbk | 87 | | Yes | 1 |
| latin5_turkish_ci | latin5 | 30 | Yes | Yes | 1 |
| latin5_bin | latin5 | 78 | | Yes | 1 |
| armscii8_general_ci | armscii8 | 32 | Yes | Yes | 1 |
| armscii8_bin | armscii8 | 64 | | Yes | 1 |
| utf8_general_ci | utf8 | 33 | Yes | Yes | 1 |
| utf8_bin | utf8 | 83 | | Yes | 1 |
| utf8_unicode_ci | utf8 | 192 | | Yes | 8 |
| utf8_icelandic_ci | utf8 | 193 | | Yes | 8 |
| utf8_latvian_ci | utf8 | 194 | | Yes | 8 |
| utf8_romanian_ci | utf8 | 195 | | Yes | 8 |
| utf8_slovenian_ci | utf8 | 196 | | Yes | 8 |
| utf8_polish_ci | utf8 | 197 | | Yes | 8 |
| utf8_estonian_ci | utf8 | 198 | | Yes | 8 |
| utf8_spanish_ci | utf8 | 199 | | Yes | 8 |
| utf8_swedish_ci | utf8 | 200 | | Yes | 8 |
| utf8_turkish_ci | utf8 | 201 | | Yes | 8 |
| utf8_czech_ci | utf8 | 202 | | Yes | 8 |
| utf8_danish_ci | utf8 | 203 | | Yes | 8 |
| utf8_lithuanian_ci | utf8 | 204 | | Yes | 8 |
| utf8_slovak_ci | utf8 | 205 | | Yes | 8 |
| utf8_spanish2_ci | utf8 | 206 | | Yes | 8 |
| utf8_roman_ci | utf8 | 207 | | Yes | 8 |
| utf8_persian_ci | utf8 | 208 | | Yes | 8 |
| utf8_esperanto_ci | utf8 | 209 | | Yes | 8 |
| utf8_hungarian_ci | utf8 | 210 | | Yes | 8 |
| utf8_sinhala_ci | utf8 | 211 | | Yes | 8 |
| utf8_general_mysql500_ci | utf8 | 223 | | Yes | 1 |
| ucs2_general_ci | ucs2 | 35 | Yes | Yes | 1 |
| ucs2_bin | ucs2 | 90 | | Yes | 1 |
| ucs2_unicode_ci | ucs2 | 128 | | Yes | 8 |
| ucs2_icelandic_ci | ucs2 | 129 | | Yes | 8 |
| ucs2_latvian_ci | ucs2 | 130 | | Yes | 8 |
| ucs2_romanian_ci | ucs2 | 131 | | Yes | 8 |
| ucs2_slovenian_ci | ucs2 | 132 | | Yes | 8 |
| ucs2_polish_ci | ucs2 | 133 | | Yes | 8 |
| ucs2_estonian_ci | ucs2 | 134 | | Yes | 8 |
| ucs2_spanish_ci | ucs2 | 135 | | Yes | 8 |
| ucs2_swedish_ci | ucs2 | 136 | | Yes | 8 |
| ucs2_turkish_ci | ucs2 | 137 | | Yes | 8 |
| ucs2_czech_ci | ucs2 | 138 | | Yes | 8 |
| ucs2_danish_ci | ucs2 | 139 | | Yes | 8 |
| ucs2_lithuanian_ci | ucs2 | 140 | | Yes | 8 |
| ucs2_slovak_ci | ucs2 | 141 | | Yes | 8 |
| ucs2_spanish2_ci | ucs2 | 142 | | Yes | 8 |
| ucs2_roman_ci | ucs2 | 143 | | Yes | 8 |
| ucs2_persian_ci | ucs2 | 144 | | Yes | 8 |
| ucs2_esperanto_ci | ucs2 | 145 | | Yes | 8 |
| ucs2_hungarian_ci | ucs2 | 146 | | Yes | 8 |
| ucs2_sinhala_ci | ucs2 | 147 | | Yes | 8 |
| ucs2_general_mysql500_ci | ucs2 | 159 | | Yes | 1 |
| cp866_general_ci | cp866 | 36 | Yes | Yes | 1 |
| cp866_bin | cp866 | 68 | | Yes | 1 |
| keybcs2_general_ci | keybcs2 | 37 | Yes | Yes | 1 |
| keybcs2_bin | keybcs2 | 73 | | Yes | 1 |
| macce_general_ci | macce | 38 | Yes | Yes | 1 |
| macce_bin | macce | 43 | | Yes | 1 |
| macroman_general_ci | macroman | 39 | Yes | Yes | 1 |
| macroman_bin | macroman | 53 | | Yes | 1 |
| cp852_general_ci | cp852 | 40 | Yes | Yes | 1 |
| cp852_bin | cp852 | 81 | | Yes | 1 |
| latin7_estonian_cs | latin7 | 20 | | Yes | 1 |
| latin7_general_ci | latin7 | 41 | Yes | Yes | 1 |
| latin7_general_cs | latin7 | 42 | | Yes | 1 |
| latin7_bin | latin7 | 79 | | Yes | 1 |
| utf8mb4_general_ci | utf8mb4 | 45 | Yes | Yes | 1 |
| utf8mb4_bin | utf8mb4 | 46 | | Yes | 1 |
| utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 8 |
| utf8mb4_icelandic_ci | utf8mb4 | 225 | | Yes | 8 |
| utf8mb4_latvian_ci | utf8mb4 | 226 | | Yes | 8 |
| utf8mb4_romanian_ci | utf8mb4 | 227 | | Yes | 8 |
| utf8mb4_slovenian_ci | utf8mb4 | 228 | | Yes | 8 |
| utf8mb4_polish_ci | utf8mb4 | 229 | | Yes | 8 |
| utf8mb4_estonian_ci | utf8mb4 | 230 | | Yes | 8 |
| utf8mb4_spanish_ci | utf8mb4 | 231 | | Yes | 8 |
| utf8mb4_swedish_ci | utf8mb4 | 232 | | Yes | 8 |
| utf8mb4_turkish_ci | utf8mb4 | 233 | | Yes | 8 |
| utf8mb4_czech_ci | utf8mb4 | 234 | | Yes | 8 |
| utf8mb4_danish_ci | utf8mb4 | 235 | | Yes | 8 |
| utf8mb4_lithuanian_ci | utf8mb4 | 236 | | Yes | 8 |
| utf8mb4_slovak_ci | utf8mb4 | 237 | | Yes | 8 |
| utf8mb4_spanish2_ci | utf8mb4 | 238 | | Yes | 8 |
| utf8mb4_roman_ci | utf8mb4 | 239 | | Yes | 8 |
| utf8mb4_persian_ci | utf8mb4 | 240 | | Yes | 8 |
| utf8mb4_esperanto_ci | utf8mb4 | 241 | | Yes | 8 |
| utf8mb4_hungarian_ci | utf8mb4 | 242 | | Yes | 8 |
| utf8mb4_sinhala_ci | utf8mb4 | 243 | | Yes | 8 |
| cp1251_bulgarian_ci | cp1251 | 14 | | Yes | 1 |
| cp1251_ukrainian_ci | cp1251 | 23 | | Yes | 1 |
| cp1251_bin | cp1251 | 50 | | Yes | 1 |
| cp1251_general_ci | cp1251 | 51 | Yes | Yes | 1 |
| cp1251_general_cs | cp1251 | 52 | | Yes | 1 |
| utf16_general_ci | utf16 | 54 | Yes | Yes | 1 |
| utf16_bin | utf16 | 55 | | Yes | 1 |
| utf16_unicode_ci | utf16 | 101 | | Yes | 8 |
| utf16_icelandic_ci | utf16 | 102 | | Yes | 8 |
| utf16_latvian_ci | utf16 | 103 | | Yes | 8 |
| utf16_romanian_ci | utf16 | 104 | | Yes | 8 |
| utf16_slovenian_ci | utf16 | 105 | | Yes | 8 |
| utf16_polish_ci | utf16 | 106 | | Yes | 8 |
| utf16_estonian_ci | utf16 | 107 | | Yes | 8 |
| utf16_spanish_ci | utf16 | 108 | | Yes | 8 |
| utf16_swedish_ci | utf16 | 109 | | Yes | 8 |
| utf16_turkish_ci | utf16 | 110 | | Yes | 8 |
| utf16_czech_ci | utf16 | 111 | | Yes | 8 |
| utf16_danish_ci | utf16 | 112 | | Yes | 8 |
| utf16_lithuanian_ci | utf16 | 113 | | Yes | 8 |
| utf16_slovak_ci | utf16 | 114 | | Yes | 8 |
| utf16_spanish2_ci | utf16 | 115 | | Yes | 8 |
| utf16_roman_ci | utf16 | 116 | | Yes | 8 |
| utf16_persian_ci | utf16 | 117 | | Yes | 8 |
| utf16_esperanto_ci | utf16 | 118 | | Yes | 8 |
| utf16_hungarian_ci | utf16 | 119 | | Yes | 8 |
| utf16_sinhala_ci | utf16 | 120 | | Yes | 8 |
| cp1256_general_ci | cp1256 | 57 | Yes | Yes | 1 |
| cp1256_bin | cp1256 | 67 | | Yes | 1 |
| cp1257_lithuanian_ci | cp1257 | 29 | | Yes | 1 |
| cp1257_bin | cp1257 | 58 | | Yes | 1 |
| cp1257_general_ci | cp1257 | 59 | Yes | Yes | 1 |
| utf32_general_ci | utf32 | 60 | Yes | Yes | 1 |
| utf32_bin | utf32 | 61 | | Yes | 1 |
| utf32_unicode_ci | utf32 | 160 | | Yes | 8 |
| utf32_icelandic_ci | utf32 | 161 | | Yes | 8 |
| utf32_latvian_ci | utf32 | 162 | | Yes | 8 |
| utf32_romanian_ci | utf32 | 163 | | Yes | 8 |
| utf32_slovenian_ci | utf32 | 164 | | Yes | 8 |
| utf32_polish_ci | utf32 | 165 | | Yes | 8 |
| utf32_estonian_ci | utf32 | 166 | | Yes | 8 |
| utf32_spanish_ci | utf32 | 167 | | Yes | 8 |
| utf32_swedish_ci | utf32 | 168 | | Yes | 8 |
| utf32_turkish_ci | utf32 | 169 | | Yes | 8 |
| utf32_czech_ci | utf32 | 170 | | Yes | 8 |
| utf32_danish_ci | utf32 | 171 | | Yes | 8 |
| utf32_lithuanian_ci | utf32 | 172 | | Yes | 8 |
| utf32_slovak_ci | utf32 | 173 | | Yes | 8 |
| utf32_spanish2_ci | utf32 | 174 | | Yes | 8 |
| utf32_roman_ci | utf32 | 175 | | Yes | 8 |
| utf32_persian_ci | utf32 | 176 | | Yes | 8 |
| utf32_esperanto_ci | utf32 | 177 | | Yes | 8 |
| utf32_hungarian_ci | utf32 | 178 | | Yes | 8 |
| utf32_sinhala_ci | utf32 | 179 | | Yes | 8 |
| binary | binary | 63 | Yes | Yes | 1 |
| geostd8_general_ci | geostd8 | 92 | Yes | Yes | 1 |
| geostd8_bin | geostd8 | 93 | | Yes | 1 |
| cp932_japanese_ci | cp932 | 95 | Yes | Yes | 1 |
| cp932_bin | cp932 | 96 | | Yes | 1 |
| eucjpms_japanese_ci | eucjpms | 97 | Yes | Yes | 1 |
| eucjpms_bin | eucjpms | 98 | | Yes | 1 |
+--------------------------+----------+-----+---------+----------+---------+
197 rows in set (0.03 sec)
mysql>
mysql> show global variables like '%char%';
+--------------------------+----------------------------------+
| Variable_name | Value |
+--------------------------+----------------------------------+
| character_set_client | latin1 |
| character_set_connection | latin1 |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | latin1 |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | /usr/local/mysql/share/charsets/ |
+--------------------------+----------------------------------+
8 rows in set (0.00 sec)
mysql>
大对象存的是指针,指向他处,所以无法创建索引,也不能设默认值
numeric(g,f) 括号里,总长度,精度
decimal(g,f) 括号里,总长度,精度
real 有时候相当于 float ,有时候相当于double(在不同的平台上不一样)(这个用得不多)
修饰符 auto_increment
主键或唯一键索引,
不能为空,
整形,
只能是正数(unsigned)
例 create table test (id int unsigned auto_increment not null primary key,name char(20))
last_insert_id() 函数,显示上一次的序列是几
所有的函数 select 函数名()
比如 select database(); select last_insert_id();
所有的存储过程 使用 call 存储过程
float(g,f): g:一共多长,f:浮点多少位
double(g,f): g:一共多长,f:浮点多少位
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 18
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> use mysql;
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| mysql |
+------------+
1 row in set (0.00 sec)
mysql>
mysql> select last_insert_id();
+------------------+
| last_insert_id() |
+------------------+
| 0 |
+------------------+
1 row in set (0.00 sec)
mysql>
not null , null ,default, auto_increment
unsigned:无符号 ( 0 和 正整数 )
zerofill: 多一位用 0 填充,(用得少)
tinyint(1) 数值型,这里(1)表示显示出1位
boolean
bool
日期,时间,日期时间 都支持时区
timestamp 没有时区的概念,就是格尼尼治时间戳,然后转为当地时间
修饰符: not null ,null ,default
datetime(8字节) 比 date(3字节)+time(3字节) 多两个字节
enum,set都是字符型
enum: 最多 65535 种变化
例如 DNS
RRtype CHAR(5) #不理想 ( RRtype: rescource record type)
(A,PTR,CNAME,AAAA,NS,SOA,SRV,TXT)
RRtype ENUM('A','PTR','CNAME','AAAA','NS','SOA','SRV','TXT') #只能从中选择,比较好
set:在表中存的是下标, 它是不能作为索引字段的
SQL模型 (模式): 违反sql规则,采取的处理机制 abc,abcdefg
CHAR(3) 是丢弃,还是只存前3个
Mysql 其实尽量让模式与其它数据库兼容
ANSI_QUOTES: " 双引号 相当于 反引号 ` (引用字段名称表名,等) , ' 单引号 被当作字符串
INNORE_SPACE: 在内建函数中忽略多余的空白字符
STRICT_ALL_TABLES: (最严格的法则)只要违反规则的数据,不允许填入,并且会返回错误的
STRICT_TRANS_TABLES: 向一个支持事务的表当中,插入非法数据时,是不允许的,而且返回一个错误
TRADITIONAL 传统的
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 19
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show global variables like 'sql_mode'; #由结果,看到没有定义 sql 模型
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| sql_mode | |
+---------------+-------+
1 row in set (0.00 sec)
mysql>
mysql 变量
状态变量
服务器变量
按作用域分类两类:
全局
show global variables
跟用户没关系,服务器启动后就生效了
只有root (或有管理权限的用户) 才能改
会话变量
show [session] variables # session 是可省的
每一次客户端连到mysql上去,只对当前会话生效的变量(会话终止就生效了)
普通用户就能改
按生效时间,分为两类:
可动态调整的: 调整后 立即生效 (可即时修改)
静态的:调整后,要重启mysql服务器才能生效,但是改的全局变量值因重启就没了;;所以静态的必须写在配置文件中或者通过参数传递给mysqld(mysqld_safe)进程
动态调整参数的生效方式:
全局: 对当前会话无效,只对新建会话有效 (好像有点改profile文件,要另打开putty才生效)
会话:即时生效,但只对当前会话有效,
服务器变量(内置变量):@@变量名 两个艾特变量名
显示: select
设定: set [global|sesssion] 变量名='value'
/etc/my.cnf 全局
~/.my.cnf 局部 ,局部覆盖全局
默认情况下新建立会话变量 是从全局继承的,继承完可以自再修改
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 19
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
mysql> show global variables like 'sql_mode';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| sql_mode | |
+---------------+-------+
1 row in set (0.00 sec)
mysql> show variables like 'sql_mode';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| sql_mode | |
+---------------+-------+
1 row in set (0.00 sec)
mysql>
mysql> select @@global.sql_mode; #用两个@表示调用服务器变量 两个艾特变量名
# 一个@表示用户自定义变量
+-------------------+
| @@global.sql_mode |
+-------------------+
| |
+-------------------+
1 row in set (0.00 sec)
mysql> select @@sql_mode;
+------------+
| @@sql_mode |
+------------+
| |
+------------+
1 row in set (0.00 sec)
mysql> select @@session.sql_mode; #session 变量,session其实是可以省略的
+--------------------+
| @@session.sql_mode |
+--------------------+
| |
+--------------------+
1 row in set (0.00 sec)
mysql>
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 20
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> set global sql_mode='strict_all_tables'; #修改全局的
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> select @@session.sql_mode; #对会话不起作用
+--------------------+
| @@session.sql_mode |
+--------------------+
| |
+--------------------+
1 row in set (0.00 sec)
mysql> select @@global.sql_mode; # 对全局有效
+-------------------+
| @@global.sql_mode |
+-------------------+
| STRICT_ALL_TABLES |
+-------------------+
1 row in set (0.00 sec)
mysql>
重开一个putty窗口
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 21
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select @@sql_mode; #不加session 就是会话,所以说上面动态调整全局的,对当前会话无效,对这里新建会话有效
+-------------------+
| @@sql_mode |
+-------------------+
| STRICT_ALL_TABLES |
+-------------------+
1 row in set (0.00 sec)
mysql>
mysql> set session sql_mode='strict_trans_tables'; #在这里改会话变量,只对当前会话有效
Query OK, 0 rows affected (0.00 sec)
mysql>
mysql> select @@sql_mode; # 看到了,此时当前会话有效了 (session是可以省掉的)
+---------------------+
| @@sql_mode |
+---------------------+
| STRICT_TRANS_TABLES |
+---------------------+
1 row in set (0.00 sec)
mysql>
mysql> select @@global.sql_mode; # 对全局是无效的
+-------------------+
| @@global.sql_mode |
+-------------------+
| STRICT_ALL_TABLES |
+-------------------+
1 row in set (0.00 sec)
mysql>
再重开一个putty窗口
[root@mail ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 22
Server version: 5.5.28-log Source distribution
Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select @@global.sql_mode; # 上一个putty窗口改的会话session,不起作用
+-------------------+
| @@global.sql_mode |
+-------------------+
| STRICT_ALL_TABLES |
+-------------------+
1 row in set (0.00 sec)
mysql> select @@sql_mode; # 上一个putty窗口改的会话session,不起作用
+-------------------+
| @@sql_mode |
+-------------------+
| STRICT_ALL_TABLES |
+-------------------+
1 row in set (0.00 sec)
mysql>