下面哪个表达式不能获取user对象的username属性（ ）。
A: ${user['username'] }
B: ${user[username] }
C: ;
D: ${user.username }
A: ${user['username'] }
B: ${user[username] }
C: ;
D: ${user.username }
举一反三
- 下面哪个表达式不能获取user对象的username属性（）。
- 删除用户的同时删除用户所拥有的全部对象的正确命令是（） A: drop user username cascade B: drop user username C: delete user username D: delete user username cascade
- 下面选项中,能够更新user表中数据的SQL语句是() A: update into user set id = 'u001'; B: update user set id = 'u001' and username='jack'; C: update user set username='jack' where id = 1; D: update into user set id = 'u001', username='jack';
- 用户表user中存在一个名字字段username,现查询名字字段中包含"凤"的用户,下列SQL语句中,正确的是() A: select * from user where username = '凤'; B: select * from user where username like '%凤%'; C: select * from user where username like '_凤_'; D: select * from user where username like '凤';
- 以下语句哪个是正确的Select查询语句( ) A: select * from use B: select distinct username user; C: select * from user where ; D: select * from user username=’李四’;