数据库连接(Windows本地数据库连接)
// .NET Framework Data Provider for SQL Server 信任连接的一种写法
Server=myServerAddress;Database=myDataBase;Trusted_Connection=True;
SqlConnection con = new SqlConnection();
try
{
//要链接的数据 要操作的数据库文件
con.ConnectionString = "Server=localhost;Database=TestDB;Trusted_Connection=true;";
con.Open();
Console.WriteLine("数据库连接成功");
}
catch(Exception e){
Console.WriteLine(e);
}
Sql语句编写(查询)
//确定连接编写数据库语句
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = "select * from UserT;";
//提交sql语句
SqlDataAdapter adapter = new SqlDataAdapter();
adapter.SelectCommand = cmd;
//得到返回结果
DataSet ds = new DataSet();
adapter.Fill(ds);
//手动释放数据库连接资源 后期熟练直接引用using直接自动释放
con.Close();
//保存数据库信息
DataTable table = ds.Tables[0];
得到返回结果并显示(for循环方法)
//展示数据
for (int i =0;i< table.Rows.Count;i++) {
Console.WriteLine("id:\t"+table.Rows[i]["id"]+ "Username:\t" + table.Rows[i]["Username"] + "password:\t" + table.Rows[i]["password"] );
}
Sql语句编写(插入)
//确定连接编写数据库语句
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
//插入数据 id是主键自增
string Username = "心态96";
string Password = "123456";
//如果想添加多行在values后加 ,('','')即可
cmd.CommandText = $"insert into UserT values ('{Username}','{Password}')";
//count会根据()多少提示成功添加行数
int count = cmd.ExecuteNonQuery();
con.Close();
Console.WriteLine($"信息添加成功新增{count}行");
Console.ReadKey();
Sql语句编写(删除)
//确定连接编写数据库语句
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
//删除语句
cmd.CommandText = $"delete from UserT where userName='123'";
//count会根据()多少提示成功删除行数
int count = cmd.ExecuteNonQuery();
con.Close();
Console.WriteLine($"信息删除成功删除{count}行");
Console.ReadKey();
Sql语句编写(修改)
//确定连接编写数据库语句
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
//设置用户名和修改密码
string Username = "心态69";
string Password = "123456789";
//删除语句
cmd.CommandText = $"update UserT set Password='{Password}' where Username='{Username}'";
//count会根据()多少提示成功删除行数
int count = cmd.ExecuteNonQuery();
con.Close();
Console.WriteLine($"信息修改成功修改影响{count}行");
Console.ReadKey();