摘要：
--创建表格createtableT_ HQ_XS（xuehVARCHAR2（10）notnull，xingmVARCHAR（20）notnull；xingbCHAR（1）默认'1'，nialNUMBER，砖瓦查尔2（20））--将注释添加到列T_ HQ-XS的注释中。学号；注释
-- Create table create table T_HQ_XS ( xueh VARCHAR2(10) not null, xingm VARCHAR2(20) not null, xingb CHAR(1) default '1', nianl NUMBER, zhuany VARCHAR2(20) ) -- Add comments to the columns comment on column T_HQ_XS.xueh is '学号'; comment on column T_HQ_XS.xingm is '姓名'; comment on column T_HQ_XS.xingb is '性别 1-男,2-女'; comment on column T_HQ_XS.nianl is '年龄'; comment on column T_HQ_XS.zhuany is '专业'; -- Create/Recreate primary, unique and foreign key constraints alter table T_HQ_XS add constraint PK_T_HQ_XS primary key (XUEH) -- Create/Recreate check constraints alter table T_HQ_XS add constraint CHECK_T_HQ_XS_NIANL check (NIANL > 8 AND NIANL < 50); alter table T_HQ_XS add constraint CHECK_T_HQ_XS_XINGB check (XINGB = '1' OR XINGB = '2');