数据库语句

oracle：

//在cmd模式下登录数据库
sqlplus
sys as sysdba
//建立表空间
create tablespace zjl datafile 'd:\zjl.dbf' size 20m;
//创建用户
create user zjl identified by zjl default tablespace zjl;
//授权
grant connect,resource to zjl;
//切换用户
conn zjl/zjl;
//创建userinfos表
create table userinfos(
    userid number(10) primary key not null,
      username varchar(20) not null,
      birthday date not null
);
//创建cards表
create table cards(
    cardid number(10) primary key not null,
      userid number(10) references userinfos(userid) not null,
      balance number(10,2) not null
);
//创建序列
create sequence seq_userid;
create sequence seq_cardid;
//插入第一张表数据
begin 
for rn in 1..22 loop
insert into userinfos values(seq_userid.nextval,dbms_random.string('a',6),sysdate+rn);
end loop;
commit;
end;
/

//使用游标给第二张表插入数据
declare 
cursor cs is select userid from userinfos;
begin 
for rn in cs loop
insert into cards values(seq_cardid.nextval,rn.userid,trunc(dbms_random.value(100,1000),2));
end loop;
commit;
end;
/

//创建表之后再创建主键及外键的写法如下：
//创建userinfos表的主键
alter table userinfos add constraint PK_userid primary key (userid);
//创建cards表的主键及外键
alter table cards add constraint PK_cardid primary key (cardid);
alter table cards add constraint FK_user_card foreign key (userid) references userinfos(userid); 

//删除表空间
drop tablespace userinfos including contents and datafiles;
//删除用户
drop user zjx cascade;

mysql:

mysql -u root -p
create database goods;
use goods;
create table customs(
        custid int primary key auto_increment not null,
        account varchar(20) not null,
        password varchar(40) not null,
        address varchar(50) not null,
        telephone varchar(11) not null
        );
create table goods(
        goodid int primary key auto_increment not null,
        title varchar(50) not null,
        pirce numeric(10,2) not null,
        picture varchar(40) not null,
        shop varchar(50) not null,
        store int not null
        );
create table buycar(
        carid int primary key auto_increment not null,
        buydate date not null,
        custid int not null
        );
        
create table carandgood(
        cagid int primary key auto_increment not null,
        carid int not null,
        goodid int not null,
        buynum int not null
    );
create table orders(
        orderid int primary key auto_increment not null,
        orderdate date not null,
        custid int not null
        );
create table orderandgood(
        oagid int primary key auto_increment not null,
        goodid int not null,
        orderid int not null,
        ordernum int not null
        );
alter table buycar add constraint FK_cust_car foreign key (custid) references customs(custid);
alter table carandgood add constraint FK_car_cag foreign key (carid) references buycar(carid);
alter table carandgood add constraint FK_good_cag foreign key (goodid) references goods(goodid);
alter table orderandgood add constraint FK_good_oag foreign key (goodid) references goods(goodid);
alter table orderandgood add constraint FK_order_oag foreign key (orderid) references orders (orderid);
alter table orders add constraint FK_cust_order foreign key (custid) references customs (custid);

insert into customs(account,password,address,telephone) values('admin','123456','南京晓航路','18652');

insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',1000,'good.jpg','Themis',200);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',456,'good.jpg','句句句',123);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',7889,'good.jpg','谷歌',134);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',567,'good.jpg','订单',156);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',89,'good.jpg','搜索',167);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',45,'good.jpg','广告',234);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',45,'good.jpg','解决',234);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',345,'good.jpg','UI哦',3435);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',678,'good.jpg','儿童',23);
insert into goods(title,pirce,picture,shop,store) values('物美价廉，货品有限',3456,'good.jpg','好几款',56);