mysql操作之常用操作——數(shù)據(jù)庫和數(shù)據(jù)表的基本操作(1)共2課

?##  ?##  ?##  ?##?????????????文件包含：???數(shù)據(jù)庫和數(shù)據(jù)表的CRUD操作?  ?##  ?##?????????????其中包含：???數(shù)據(jù)庫和數(shù)據(jù)表的：  ?##?????????????????????????????????????????數(shù)據(jù)庫的字符集修改  ?##?????????????????????????????????????????數(shù)據(jù)表的名字?字段信息?等操作  ?##  ?##  ?##???//?+----------------------------------------------------------------------  ?##???//?|?數(shù)據(jù)庫操作  ?##???//?|?1.增------------創(chuàng)建數(shù)據(jù)庫  ?##???//?|?2.刪------------刪除數(shù)據(jù)庫  ?##???//?|?3.改------------修改數(shù)據(jù)庫  ?##???//?|?3.查------------查詢數(shù)據(jù)庫創(chuàng)建  ?##???//?+----------------------------------------------------------------------#  ?##????????  ?##  ?##  ?#1.數(shù)據(jù)庫創(chuàng)建語句  create?database??`liu1`?character?set?utf8??collate?utf8_general_ci  ?#2.刪除數(shù)據(jù)庫創(chuàng)建語句??  drop?database?if?exists?`liu1`;  ?#3.修改數(shù)據(jù)庫創(chuàng)建語句?  alter?database?`liu1`?charset?=?utf8  alter?database?`liu1`?collate?utf8_general_ci;utf8_slovenian_ci  ?#4.查看數(shù)據(jù)庫創(chuàng)建語句??  show?create?database?`liu1`;  ?##  ?##  ?##  ?##???//?+----------------------------------------------------------------------  ?##???//?|?數(shù)據(jù)表操作  ?##???//?|?1.增------------創(chuàng)建表  ?##???//?|?2.刪------------刪除表  ?##???//?|?3.改------------修改表  ?##???//?|?4.查------------查看表創(chuàng)建語句  ?##???//?+----------------------------------------------------------------------#  ?##????????  ?##  ?##  ##################################字段類型查詢#####################################################  #整型  #???????????1）tinyint???1字節(jié)??-128?????127??????UNSIGNED???255  #???????????2）SMALLINT??2字節(jié)??-32768???32767????UNSIGNED???65535  #???????????3）MEDIUMINT?3字節(jié)??-8388608?8388607??UNSIGNED???16777215  #???????????4）INT???????4字節(jié)??-2147483648?2147483647???UNSIGNED????4294967295  #???????????5）BIGINT????8字節(jié)??-9223372036854775808????9223372036854775807??UNSIGNED?18446744073709551615  #小數(shù)型  #???????????1）float(4,2)???范圍??-99.99-99.99??UNSIGNED?0-99.99?(丟失精度)  #???????????2）decimal(4,2)?范圍??-99.99-99.99??UNSIGNED?0-99.99  #時(shí)間  #???????????1）date??????????格式：2017-11-12(沒有時(shí)分秒)  #???????????2）datetime??????格式：2017-11-12?12:12:12  #???????????3）timestamp?????格式：2017-11-12?12:12:12(當(dāng)插入數(shù)據(jù)時(shí)，默認(rèn)插入系統(tǒng)當(dāng)前時(shí)間)  #多選???????set(1,2,3,4)?????格式：字段名(屬性1，屬性2，屬性3)?insert?into?`liu1`?values('1,2,4');  #?????????????????????????????????select?*?from?liu1?where?find_in_set('1查詢的選項(xiàng)','hobby查詢的字段名')  #單選???????enum(1,2,3,4)????格式：字段名(屬性1，屬性2，屬性3)?insert?into?`liu1`?values('1');  #  #字符串  #???????????1）char??????????范圍??1-255字節(jié)  #???????????2）varchar???????范圍??1-65535字節(jié)(21844漢字)  #???????????3）text??????????  ##################################字段類型查詢#####################################################    ##################################1.表創(chuàng)建語句#####################################################  CREATE?TABLE?IF?NOT?EXISTS?`admin`(??  ????`adminid`?INT?UNSIGNED?NOT?NULL?AUTO_INCREMENT?COMMENT?'主鍵ID',?  ????`adminuser`?VARCHAR(32)?NOT?NULL?DEFAULT?''?COMMENT?'管理員賬號(hào)',??  ????`adminpass`?CHAR(32)?NOT?NULL?DEFAULT?''?COMMENT?'管理員密碼',??  ????`adminemail`?VARCHAR(50)?NOT?NULL?DEFAULT?''?COMMENT?'管理員電子郵箱',??  ????`logintime`?INT?UNSIGNED?NOT?NULL?DEFAULT?'0'?COMMENT?'登陸時(shí)間',??  ????`loginip`?BIGINT?NOT?NULL?DEFAULT?'0'?COMMENT?'登陸IP',??  ????`createtime`?INT?UNSIGNED?NOT?NULL?DEFAULT?'0'?COMMENT?'創(chuàng)建時(shí)間',??  ????`repasssendmailtime`?INT?UNSIGNED?NOT?NULL?DEFAULT?'0'?COMMENT?'密碼修改時(shí)間',  ????`repasssedradint`?INT?UNSIGNED?NOT?NULL?DEFAULT?'0'?COMMENT?'密碼修改隨機(jī)數(shù)字',  ????PRIMARY?KEY(`adminid`),??  ????UNIQUE?shop_admin_adminuser_adminpass(`adminuser`,`adminpass`),??  ????UNIQUE?shop_admin_adminuser_adminemail(`adminuser`,`adminemail`)??  ??  )ENGINE=InnoDB?DEFAULT?CHARSET=utf8;??    INSERT?INTO?`admin`(adminuser,adminpass,adminemail,createtime)?  VALUES  ('admin',md5('admin'),'857523518@qq.com',UNIX_TIMESTAMP()),  ('admin',md5('admin'),'857523518@qq.com',UNIX_TIMESTAMP());  #UNSIGNED????表示無符號(hào)  #PRIMARY?KEY?主鍵?一張表中只能有一個(gè)主鍵，表示該字段的數(shù)據(jù)不能重復(fù)?自帶不能為空屬性  #PRIMARY?KEY(`adminid?name`)?復(fù)合主鍵?表示2個(gè)字段的數(shù)據(jù)都不可能重復(fù)  #UNIQUE?KEY?唯一鍵???一個(gè)表中可以多個(gè)唯一鍵??可以為空，而且空字段不參與唯一性比較  ##################################2.刪除表語句#####################################################  DROP?TABLE?IF?EXISTS?`admin`;  ##################################3.修改表語句#####################################################  #1.修改表名  alter?table?admin1?RENAME?TO?admin2;  #2.修改表字符集  alter?table?`admin2`?character?set?utf8  #3.修改表字段長(zhǎng)度  alter?table?`admin2`?modify?column?adminuser??varchar(32)?not?null?default?'';  #3.插入新字段  alter?table?`admin2`?add?name?varchar(6)?not?null?default?'?'?after?adminid;?(在adminid后)?  #3.刪除新字段  alter?table?liu1?drop?name;  #4.修改表字段名  alter?table?liu1?change?id?id1?varchar(16)?not?null?default?'?'（注：?后面的屬性要全部帶上）  ##################################4.查看表創(chuàng)建語句###################################################  show?create?table?admin2