1. 表相关
a. 主键：constraint [主键的约束名] primary key
b. 外键：constraint [外键约束名] foreign key( ) references []()
c. 唯一性： unique
d.条件约束： constraint ...check...
Example:
Create Table Computers(
CompNo number(4) constraint PK_Comp primary key,
CompModel number unique,
OwnerId number(4) constraint FK_Owner foreign key(OwnerId) references Member(Id),
Price number(7,2) constraint ch_price check(price >0 and price <30000)
);