??????????????
????????????????????????????????????????????????????????????Apache??????????www????????
????????DBMS??database management system(????????????)??
????1??Access:????С????????????
????2??SQL Server:?????д????????
????3??Oracle?????????????????????????????(??????)?????
????4??My SQL??????????AB???????????????????????????????????С????????????
????????????
???????????????????????????
???????????????洢???????????????????????????????п?????????????
?????????????????????????????????????У??????????????????id???????????С?
??????Σ???????? ??????????Σ????????п????ж????Σ???ι漲???е??Щ??????磺???????????????
????????????????????????ID???????????????????????е?????????????????
????????????(Mac Xampp)
????????????? xampp?е?bin?????????в?????
????·./mysql -u root -p????// ?????????
????· show databases;????  // ??????е??????
????· create database if not exists db_name charset utf8;????// ?????????
????[if not exists](???)???????????????????????????????????????д????????
????[charset utf8](???)?????????????????????????????????utf8?????????????????????
????· show create database db_name;               // ????????????????????(????????????????)??
????· drop database if exists db_name;              // ????????
????[if exists](???)????????????????????????????????
????· alter database db_name default character set utf8;       // ???????????????????
????????????
???????????洢????????е???????????????? ????????????????????use db_name;
????· show tables;                // ????????????
????· create table table_name(col_name col_type col_attrbute??col_name2 col_type2 col_attrbute);          // ??????????
????col_name????ε??????
????col_type: ??ε??????
????tinyint??0~255???????Ρ?
????int????21??????Ρ?
????bigint???????????????????
????char??????????????????????10????????????洢?????4????? ????????????10???????
????varchar???????????????????????????洢??????????????????????????????????????????? ???varchar??
????text???????????洢?????????????
????date???????
????time?????
????datetime??????+???
????col_attrbute????ε??????    // ????????ж????
????primary key?????????????ε??????????(???????ID????????????????????)
????null??not null?????????ο??????
????default???????????
????auto_increment?????????????????β???????????????????????????1??
????id??α????????β??????????3???????primary key not null auto_increment??
?????????create table news(id int primary key not null auto_increment??title varchar(100) not null??author varchar(20) not null??content text not null??hits int default 0 not null);
????describe table_name;                       // ????????
????drop table if exists table_name;        // ??????
????alter table;                                      // ????????????????? ?????????????????????????????
????MySQL????????
????· ????
????tinyint??С??????????255????????0~255 ?? -128~127??????????????255????????????????255?? ???1??????
????smallint??С??????????Χ??0~65535?????2??????
????mediumint??????????????Χ??0~1677?????3??????
????int?????????????Χ??0~21??????4??????
????bigint??????????????Χ??0~42??????8??????
????· ??????????????С??????????????????????δ????????bigint??????????????????磺GDP??
????float(M??D)????????(??????С?????7λ)???????????M??????????D????С??λ?á?
????double(M??D)???????(??????С?????15λ)????????float?????
??????????float(7??2) ??????7λ??9999999??С????λ????2λ??99999.99?? ???? ??????????????????洢99999.99???????
????· ?????????
????date????????????"YYYY-mm-dd"
????time??????????"00:00:00"
????· ?????
????char(22)?????????????????0~255???? ??? ????? ?綽????
????varchar(50)???????????????0~65535.
????· ?????
????tinytext??0~255???????С???????
????text??0~1670????????????????
????longtext??0~42?????????????????