MySQL瀛楃闆�
1銆佸熀鏈蹇�
瀛楃(Character)锛� 聽 聽 聽 聽鏄寚浜虹被璇█涓渶灏忕殑琛ㄤ箟绗﹀彿銆備緥濡�'A'銆�'B'绛夛紱
缂栫爜锛圗ncoding锛夛細 聽 聽缁欏畾涓�绯诲垪瀛楃锛屽姣忎釜瀛楃璧嬩簣涓�涓暟鍊硷紝鐢ㄦ暟鍊兼潵浠ｈ〃瀵瑰簲鐨勫瓧绗︼紝杩欎竴鏁板�煎氨鏄瓧绗︾殑缂栫爜
瀛楃闆�(Character Set):缁欏畾涓�绯诲垪瀛楃骞惰祴浜堝搴旂殑缂栫爜鍚庯紝鎵�鏈夎繖浜涘瓧绗﹀拰缂栫爜瀵圭粍鎴愮殑闆嗗悎灏辨槸瀛楃闆�
瀛楃搴�(Collation) 锛� 聽 聽 鎸囧湪鍚屼竴瀛楃闆嗗唴瀛楃涔嬮棿鐨勬瘮杈冭鍒�
涓�涓瓧绗﹂泦鍙互瀵瑰簲澶氱瀛楃搴忥紱
浠ュ瓧绗﹀簭瀵瑰簲鐨勫瓧绗﹂泦鍚嶇О寮�澶达細
浠ci(琛ㄧず澶у皬鍐欎笉鏁忔劅)锛屼緥濡傦細鍦ㄥ瓧绗﹀簭``utf8_general_ci''涓嬶紝瀛楃``a''鍜宍`A''鏄瓑浠风殑锛�
_cs(琛ㄧず澶у皬鍐欐晱鎰�)鎴朹bin(琛ㄧず鎸夌紪鐮佸�兼瘮杈�)缁撳熬銆�
鏈夊摢浜涘父鐢ㄧ殑瀛楃闆�
mysql涓瓧绗﹂泦 utf8 鍜寀tf8mb4 鏈変粈涔堝尯鍒�?
杩欎釜utf8mb4 鏄痬ysql5.5鎵嶆湁鐨勫瓧绗︿簡锛屽彲浠ョ畝鍗曠殑鐞嗚В utf8mb4 鏄洰鍓嶆渶澶х殑涓�涓瓧绗︾紪鐮�,鏀寔浠绘剰鏂囧瓧.
涓轰粈涔堜細鏈塙TF8MB4锛�
MySQL鏀寔鐨剈tf8缂栫爜锛屾渶澶у瓧绗﹂暱搴︿负 3 瀛楄妭锛屽鏋滈亣鍒� 4 瀛楄妭鐨勫瓧绗﹀氨浼氬嚭鐜伴敊璇簡銆�
涓変釜瀛楄妭鐨� UTF-8 鏈�澶ц兘缂栫爜鐨� Unicode 瀛楃鏄� 0xFFFF锛屼篃灏辨槸 Unicode 涓殑鍩烘湰澶氭枃骞抽潰锛圔MP锛夈��
涔熷氨鏄锛屼换浣曚笉鍦ㄥ熀鏈鏂囧钩闈㈢殑 Unicode瀛楃锛屾渶甯歌鐨勫氨鏄疎moji 琛ㄦ儏锛圗moji 鏄竴绉嶇壒娈婄殑 Unicode 缂栫爜锛屽父瑙佷簬 ios 鍜� android 鎵嬫満涓婏級锛屽拰涓�浜涗笉甯哥敤鐨勬眽瀛楋紝浠ュ強浠讳綍鏂板鐨� Unicode 瀛楃绛夌瓑锛岄兘鏃犳硶浣跨敤MySQL鍘熸湁鐨� utf8 瀛楃闆嗗瓨鍌ㄣ��
2銆佸瓧绗﹂泦鐩稿叧鍙橀噺
character_set_client锛氬鎴风鏉ユ簮鏁版嵁浣跨敤鐨勫瓧绗﹂泦
character_set_connection锛氳繛鎺ュ眰瀛楃闆�
character_set_results锛氭煡璇㈢粨鏋滃瓧绗﹂泦
鍐呴儴瀛楃闆嗭細
character_set_server锛氶粯璁ょ殑鍐呴儴鎿嶄綔瀛楃闆�
character_set_database锛氬綋鍓嶉�変腑鏁版嵁搴撶殑榛樿瀛楃闆�
character_set_system锛氱郴缁熷厓鏁版嵁(瀛楁鍚嶇瓑)瀛楃闆�
杩樻湁浠ollation_寮�澶寸殑鍚屼笂闈㈠搴旂殑鍙橀噺锛岀敤鏉ユ弿杩板瓧绗﹀簭銆�
鍐呴儴鎿嶄綔瀛楃闆嗕紭鍏堢骇鍏崇郴锛�
鏈嶅姟鍣ㄥ瓧绗﹂泦 server < 鏁版嵁搴撳瓧绗﹂泦database < 琛ㄥ瓧绗﹂泦 < 鍒楀瓧绗﹂泦锛屽鏋滄病鏈夎缃紝榛樿浠庝笂涓�绾х户鎵裤��
3銆佽浆鎹㈣繃绋�
MySQL Server鏀跺埌璇锋眰鏃跺皢璇锋眰鏁版嵁浠巆haracter_set_client杞崲涓篶haracter_set_connection锛�
杩涜鍐呴儴鎿嶄綔鍓嶅皢璇锋眰鏁版嵁浠巆haracter_set_connection杞崲涓哄唴閮ㄦ搷浣滃瓧绗﹂泦锛�
浣跨敤姣忎釜鏁版嵁瀛楁鐨凜HARACTER SET璁惧畾鍊硷紱
鑻ヤ笂杩板�间笉瀛樺湪锛屽垯浣跨敤瀵瑰簲鏁版嵁琛ㄧ殑DEFAULT CHARACTER SET璁惧畾鍊�(MySQL鎵╁睍锛岄潪SQL鏍囧噯)锛�
鑻ヤ笂杩板�间笉瀛樺湪锛屽垯浣跨敤瀵瑰簲鏁版嵁搴撶殑DEFAULT CHARACTER SET璁惧畾鍊硷紱
鑻ヤ笂杩板�间笉瀛樺湪锛屽垯浣跨敤character_set_server璁惧畾鍊笺��
MySQL瀛楃闆嗙患鍚堣В鎯戜互鍙婃渶浣冲疄璺�
mysql> insert into t20(name) values ('浣犲ソ');
寰�t20琛ㄧ殑name 鍒椾笂鎻掑叆鏁版嵁鈥樹綘濂解��
瀹㈡埛绔�樹綘濂解�欒杩涜浜嗙紪鐮侊紝鍋囪缂栨垚浜嗏��9190,9193鈥�
Mysql鎺ュ埌SQL璇彞涔嬪悗锛屽彂鐜版湁瀛楃
1銆両nsert
2銆乀20(name) varchar鍒楁湁瀛楃锛屽氨闇�瑕佺紪鐮�
3銆佲��9190,9193鈥�
瀹㈡埛绔�氳繃character_set_client鍛婅瘔mysql鐢ㄧ殑浠�涔堝瓧绗﹂泦缂栫爜锛宑haracter_set_client涓巆haracter_set_connection缂栫爜鏂瑰紡涓嶅悓鏃讹紝浼氳繘琛岃浆鎹€��
鍘熷垯锛氬瓨鏁版嵁鐨勬椂鍊欎笉鍙戠敓杞崲鎴栬浆鎹㈠彧鍙戠敓涓�娆★紝鍙互鍙戠敓鍦�1鎴�2
===============================
insert into t1 values ('浣�'); /select * from t1;
1銆佹瀛樻鍙栵紙瀹岀編锛�
2銆佹瀛橀敊鍙栵紙灏忎簨锛�
鍙槸character_set_results鐨勫�兼病鏈夋纭樉绀哄鎴风鐨勫瓧绗﹂泦锛屾湁鍙兘浼氬嚭鐜颁贡鐮佹儏鍐碉紝浣嗘槸鏁版嵁鐨勫瓨鍌ㄦ槸姝ｇ‘鐨�
3銆侀敊瀛樻鍙栵紙浜哄懡锛�
IMG_256
閿欏瓨姝ｅ彇鐨勮繃绋嬪垎鏋愶細
瀹㈡埛绔殑瀛楃闆嗘槸gbk锛宑haracter_set_client=character_set_connection=character_set_results 鏄� dec8锛屽亣瀹�'浣�'鍦╣bk涓殑缂栫爜鏄�001锛屽綋鍦ㄥ鎴风鎻掑叆鏁版嵁'浣�'鏃讹紝瀹㈡埛绔細鎶�'浣�' 缂栨垚001锛�001浼氫紶鍏ユ暟鎹簱锛屽綋鏁版嵁搴撴帴鏀朵俊鎭椂浼氳闂�001鏄敤浠�涔堢紪鐨勶紝character_set_client 鍛婅瘔鏁版嵁搴撴槸鐢� dec8缂栫殑锛屾暟鎹簱浼氭妸001璇戞垚dec8瀵瑰簲鐨勫瓧绗︼紝鍋囪涓�'a'锛岀劧鍚庢妸 a 缂栨垚utf8鐨勭紪鐮侊紝鍋囧畾涓�010锛屾鏃跺瓨鍏ユ暟鎹簱涓殑鏄� 'a'锛屽彇鏁版嵁鏃惰闂槸鐢ㄤ粈涔堝彇锛宑haracter_set_results鍛婅瘔鏁版嵁搴撶敤 dec8鍙栵紝鏁版嵁搴撳皢 utf8鐨�010 --> a -->dec8 鐨�001锛岀劧鍚庡湪瀹㈡埛绔細鏄剧ずgbk涓�001瀵瑰簲鐨�'浣�'
===================
鏍″瑙勫垯(collation)锛氭槸涓�缁勮鍒欙紝璐熻矗鍐冲畾鏌愪竴瀛楃闆嗗唴鐨勫瓧绗﹁繘琛屾瘮杈冨拰鎺掑簭鐨勭粨鏋�
姣忎釜瀛楃闆嗘湁涓�涓垨澶氫釜鏍″瑙勫垯锛屽苟涓旀瘡涓牎瀵硅鍒欏彧鑳藉睘浜庝竴涓瓧绗﹂泦
姣忎釜瀛楃闆嗘湁涓�涓粯璁�(default)鏍″瑙勫垯銆� utf8鐨勯粯璁ゆ牎瀵硅鍒欐槸utf8_general_ci
鏍″瑙勫垯鐨勫懡鍚嶇害瀹氾細浠ュ瓧绗﹂泦鍚嶅紑濮嬶紝涓棿鍖呮嫭涓�涓瑷�鍚嶏紝鏈�鍚庝互鍚庣紑_ci銆乢cs鎴朾in缁撴潫
*_bin:聽 binary case sensitive collation 鍖哄垎澶у皬鍐�,鐩存帴姣旇緝瀛楃鐨勭紪鐮�
*_cs: case sensitive collation聽 聽聽 鍖哄垎澶у皬鍐�
*_ci: case insensitive collation聽 涓嶅尯鍒嗗ぇ灏忓啓
Utf8
澶у皬鍐欐槸鍚︽晱鎰熺殑杩欎箞涓�涓叧浜庢瘮杈冨拰鎺掑簭鐨勫弬鏁般��
Mysql榛樿閮芥槸澶у皬鍐欎笉鏁忔劅锛岃繖浼氬奖鍝嶆帓搴忓拰where姣旇緝锛岃嫢瑕佸尯鍒嗗ぇ灏忓啓锛岄渶瑕佸湪寤哄簱锛屽缓琛紝寤哄垪鐨勬椂鍊欑壒娈婃寚瀹氫竴涓嬨��
mysql> create table t1(id int,name varchar(20));
mysql> insert into t1 values(1,'a');聽 //鎻掑叆A銆乤銆丅銆乥鍥涗釜鍊�
鐢╳here鍙栫殑鏃跺�欎笉浼氬尯鍒嗗ぇ灏忓啓
mysql> create table t2(id int,name varchar(20)) CHARACTER SET gbk CollATE=gbk_bin;聽聽 //鎸囧畾鍖哄垎澶у皬鍐�
鐢╳here鐨勬椂鍊欏氨鍖哄垎澶у皬鍐欎簡
======
create table t1(id int,name varchar(5)) character set utf8 collate=utf8_general_ci;
IMG_256
create table t2(id int,name varchar(5)) character set utf8 collate=utf8_bin;
IMG_256
======
鏌ョ湅鏁版嵁搴撴敮鎸佺殑鎵�鏈夋牎瀵硅鍒�
show collation;
鏌ョ湅褰撳墠瀛楃闆嗗拰鏍″瑙勫垯璁剧疆
show variables like 'collation_%';
IMG_256
鏉ユ簮锛� http://www.111cn.net/database/mysql/114544.htm