--建立用户信息表create table users(   users_id  varchar2(12) not null,   users_name varchar2(12) not null,   users_username varchar2(6) not null,   users_userpassword varchar2(6) not null,   users_phone number(11) not null,   users_address varchar2(60) not null   )--添加注释comment on column users.users_id    is ‘用户编号（主键）‘;comment on column users.users_name    is ‘用户姓名‘;comment on column users.users_username    is ‘用户账户登录名‘;comment on column users.users_userpassword    is ‘用户账户登录密码‘;comment on column users.users_phone    is ‘用户联系方式‘;comment on column users.users_address    is ‘用户住址‘;    --添加主键约束alter table users add constraint PK_users primary key (users_id)    --给登录名添加唯一约束alter table users add constraint UK_users unique (users_username);--添加三个信息insert into users values(‘001‘,‘张三‘,‘zhangs‘,‘666666‘,‘18865472008‘,‘阳光小区15号楼1单元102‘);insert into users values(‘002‘,‘李四‘,‘lisi01‘,‘666666‘,‘18865472009‘,‘阳光小区14号楼1单元301‘);insert into users values(‘003‘,‘王五‘,‘wangwu‘,‘666666‘,‘18865472010‘,‘阳光小区8号楼1单元402‘);--查看一下新建的users表select * from users

--建立水费缴纳情况信息表create table water(   users_id  varchar2(12) not null,          water_sfjf varchar2(3)  not null,   water_time date,   water_count number(9,2) not null,   water_price number(9,2) not null,   water_money number(9,2) not null,   water_before number(9,2) not null   )--添加注释comment on column water.users_id    is ‘用户编号（外键）‘;comment on column water.water_sfjf    is ‘上月是否缴纳水费‘;comment on column water.water_time    is ‘缴费时间‘;comment on column water.water_count    is ‘用水量（吨）‘;comment on column water.water_price    is ‘单价‘;comment on column water.water_money    is ‘本次应缴金额‘;comment on column water.water_before    is ‘截止上月共缴水费‘;    --添加外键alter table WATER add constraint FK_WATER foreign key (USERS_ID);--添加几个水费缴纳情况的信息信息insert into water values(‘001‘,‘是‘,sysdate,‘12.3‘,‘0.5‘,‘6.15‘,‘275.5‘);insert into water values(‘002‘,‘是‘,sysdate,‘16‘,‘0.5‘,‘8‘,‘395.7‘);insert into water values(‘003‘,‘否‘,‘‘,‘6‘,‘0.5‘,‘3‘,‘78.6‘);--查看一下新建的admin表select * from water