private const string SQL_INSERT_USER = "INSERT INTO Users(UserName, Password, Email, Question, Answer, CreateDate, LastLoginDate) VALUES(@UserName, @Password, @Email, @Question, @Answer, @CreateDate, @LastLoginDate)"; using (SqlDataReader sdr = SqlHelper.ExecuteReader(SqlHelper.ConnString, CommandType.Text, SQL_SELECT_USER, null))上边这两条语句麻烦详细解释一下!
private const string SQL_INSERT_USER = "INSERT INTO Users(UserName, Password, Email, Question, Answer, CreateDate, LastLoginDate) VALUES(@UserName, @Password, @Email, @Question, @Answer, @CreateDate, @LastLoginDate)"; using (SqlDataReader sdr = SqlHelper.ExecuteReader(SqlHelper.ConnString, CommandType.Text, SQL_SELECT_USER, null))上边这两条语句麻烦详细解释一下!
private const string SQL_INSERT_USER = "INSERT INTO Users(UserName, Password, Email, Question, Answer, CreateDate, LastLoginDate) VALUES(@UserName, @Password, @Email, @Question, @Answer, @CreateDate, @LastLoginDate)"; //构造一条Sql语句 using (SqlDataReader sdr = SqlHelper.ExecuteReader(SqlHelper.ConnString, CommandType.Text, SQL_SELECT_USER, null)) //调用SqlHepler里面的ExecuteReader方法返回数据阅读器
@UserName //这是变量吗?
//using可以 using()这样用?那一部分的知识
set @id=1
set @username='zhangsan'
insert into [user] values(@id,@username)2、using (SqlDataReader sdr = SqlHelper.ExecuteReader(SqlHelper.ConnString, CommandType.Text, SQL_SELECT_USER, null))
{
//在using后面括号中声明的变量sdr只能够在本{}中使用,离开{}就会被释放、关闭
}
2 使用using(...){}其中的所有资源在使用后完会自动释放掉