①主键 constraint pk_name primary key <column_name>
②外键 constraint fk_name foreign key(column_name) reference table_name(column_name)
③检查 constraint ck_name check (condition)
④唯一 constraint un_name unique (column_name)
⑤非空 <column name> <data type> not null,
⑥默认值<column name> <data type> default <default value>,
数据库创表常用约束以及案例参照
原文:http://blog.csdn.net/jian_csdn/article/details/45841155