单选题：已知定义Users表的要求：

已知定义Users表的要求：

uid属性是用户的id号，主码，自增长，起始值1；

username是用户的昵称，不重复 ，不为空，最大长度15的可变长度字符串；

password是密码，最大长度15的可变长度字符串；不为空；

下面定义User表的语句，完全正确的是( ).
@[C](2)

A. `CREATE TABLE users
( uid INT AUTO_INCREMENT PRIMARY KEY,
username CHAR(15) ,
password VARCHAR (15) not null
);
`
B. `CREATE TABLE users
( uid CHAR (10) AUTO_INCREMENT PRIMARY KEY,
username varCHAR(15) unique,
password VARCHAR (15) not null
);
`
C. `CREATE TABLE users
( uid INT AUTO_INCREMENT PRIMARY KEY,
username varCHAR(15) not null unique ,
password VARCHAR (15) not null
);
`
D. `CREATE TABLE users
( uid INT AUTO_INCREMENT PRIMARY KEY,
username CHAR(15) unique ,
password VARCHAR (15) not null
);
`




A.`CREATE TABLE users
( uid INT AUTO_INCREMENT PRIMARY KEY,
username CHAR(15) ,
password VARCHAR (15) not null
);
`
B.`CREATE TABLE users
( uid CHAR (10) AUTO_INCREMENT PRIMARY KEY,
username varCHAR(15) unique,
password VARCHAR (15) not null
);
`
C.`CREATE TABLE users
( uid INT AUTO_INCREMENT PRIMARY KEY,
username varCHAR(15) not null unique ,
password VARCHAR (15) not null
);
`
D.`CREATE TABLE users
( uid INT AUTO_INCREMENT PRIMARY KEY,
username CHAR(15) unique ,
password VARCHAR (15) not null
);
`


答案：C