黑马程序员+ADO.Net基础(上)

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1 在项目中添加数据库，当要打包项目给别人的时候，需要断开数据库的连接

2  连接SQLserver:连接到那台服务器上，那个实例那个数据库，用户名和密码

“Data Data Source=ZHANGLIANG\SQLEXPRESS;Initial Catalog=MyDB;Integrated Security=True”

连接数据库语句：SqlConnection需要using

stringconStr=@"Data Source=ZHANGLIANG\SQLEXPRESS;Initial Catalog=MyDB;Integrated Security=True";

            using(SqlConnectionconn=newSqlConnection(conStr)){

            if (conn!=null)

            {

                conn.Open();

                Console.WriteLine("Success!");               

            }}

3 插入操作：
           using( SqlConnection conn = new SqlConnection(conStr) ){

if (conn != null)

{

conn.Open();

Console.WriteLine("连接 Success!");

using (SqlCommand cmd = conn.CreateCommand())

{

cmd.CommandText = "insert into Person(name,age)values('yy',29) ";

cmd.ExecuteNonQuery();

Console.WriteLine("插入成功！");

}

}

}

4 登录练习：
           /// <summary>

/// 登录方法

/// </summary>

static void LoginMethod(string conStr) {

Console.WriteLine("输入用户名：");

string name = Console.ReadLine();

Console.WriteLine("输入密码：");

string pwd = Console.ReadLine();

using (SqlConnection conn = new SqlConnection(conStr))

{

conn.Open();

using (SqlCommand cmd=conn.CreateCommand())

{

cmd.CommandText = "select * from T_user where name='"+name+"'";

using (SqlDataReader reader=cmd.ExecuteReader())

{

if (reader.Read())//有该用户

{

if (reader.GetString(reader.GetOrdinal("password"))==pwd.Trim())//密码一致

{

Console.WriteLine("登录成功！");

}

else

{

Console.WriteLine("登录失败！");

}

}

else

{

Console.WriteLine("用户不存在！");

}

}

}

}

5        用户界面插入数据

/// <summary>

/// 插入新用户信息

/// </summary>

/// <param name="conStr"></param>

static void InsertUserInfo(string conStr) {

Console.WriteLine("输入要插入的用户名：");

string name = Console.ReadLine();

Console.WriteLine("输入密码：");

string pwd = Console.ReadLine();

using (SqlConnection conn = new SqlConnection(conStr))

{

conn.Open();

using (SqlCommand cmd=conn.CreateCommand())

{

// cmd.CommandText = "insert into T_user(name,password)values('" + name + "','" + pwd + "')";

cmd.CommandText = string.Format("insert into T_user(name,password)values('{0}','{1}')",name,pwd);

cmd.ExecuteNonQuery();

Console.WriteLine("新用户信息插入成功！");

}

}

}

6        ExecuteScalar返回第一行和第一列的结果 ：cmd.CommandText=“select cout(*) from T_user”;  cmd.ExecuteScalar();

7 获取插入数据的id值：
                    cmd.CommandText=string.Format("insert into T_user(name,password) output inserted.id values('{0}','{1}')",name,pwd);                                     Console.WriteLine(cmd.ExecuteScalar());//返回插入时的id值

8   close()与dispose()的区别： close() 后可以在Open,而dispose()后不能在open()

9  防注入漏洞攻击

/// <summary>

/// 防注册漏洞攻击

/// </summary>

/// <param name="conStr"></param>

static void CheckUserProtected(string conStr)

{

string name, pwd;

Console.WriteLine("Name:");

name = Console.ReadLine();

Console.WriteLine("Password:");

pwd = Console.ReadLine();

using(SqlConnection conn=new SqlConnection(conStr)){

conn.Open();

using (SqlCommand cmd=conn.CreateCommand())

{

cmd.CommandText = "select * from T_user where name=@Name and password=@Password";

cmd.Parameters.Add("@Name",name);

cmd.Parameters.Add("@Password",pwd);

if (Convert.ToInt32(cmd.ExecuteScalar())>0)

{

Console.WriteLine("登录成功！");

}

else

{

Console.WriteLine("登录失败！");

}

}

}

}

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