C#數據庫操作小結

2020-01-24 03:41:17

字體：大中小

來源：轉載

供稿：網友

1、常用的T-Sql語句
      查詢：SELECT * FROM tb_test WHERE ID='1' AND name='xia'
                SELECT * FROM tb_test
      插入：INSERT INTO tb_test VALUES('xia','123')
                  INSERT INTO tb_test(name) VALUES('xia')
      更新：UPDATE tb_test SET password='234' WHERE ID='1'
      刪除：DELETE FROM tb_test WHERE ID='1'
                 DELETE tb_test WHERE ID='1'
2、在vs2010中獲取數據庫連接字符串
      string connectionString = Properties.Settings.Default.DatabaseTestConnectionString;
3、SqlCommand類型
       查詢：

復制代碼代碼如下:

       using (SqlConnection connection = new SqlConnection(connectionString))
       {
             try
             {
                    SqlCommand command = new SqlCommand(selectStr, connection);
                    command.Connection.Open();
                    SqlDataReader reader = command.ExecuteReader();
                     while (reader.Read())
                             label1.Text = "name：" + reader["name"].ToString();    //數據讀取
                     command.Connection.Close();
               }
              catch (SqlException ex)
              {
                    throw ex;
              } 
       }
       

插入、修改、刪除：

復制代碼代碼如下:

       using (SqlConnection connection = new SqlConnection(connectionString))
       {
             try
             {
                    SqlCommand command = new SqlCommand(cmdStr, connection);
                    command.Connection.Open();
                    command.ExecuteNonQuery();
                    command.Connection.Close();
              }
              catch (SqlException ex)
              {
                    throw ex;
              }
      }

4、DataTable類型，查詢、添加、修改、刪除
      DataTable使用查詢、添加、刪除、修改時，需要用到SqlDataAdapter類
      string selectStr = "SELECT * FROM tb_test2";
      查詢：

復制代碼代碼如下:

      using (SqlConnection connection = new SqlConnection(connectionString))
      {
             try
             {
                    SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
                    DataTable dataTable = new DataTable();
                    adapter.Fill(dataTable);
                    //數據讀取
                    label1.Text = dataTable.Rows[0][0].ToString();
              }
             catch (SqlException ex)
             {
                     throw ex;
              }
      }
      

添加：

復制代碼代碼如下:

      using (SqlConnection connection = new SqlConnection(connectionString))
      {
           try
           {
                 SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
                 DataTable dataTable = new DataTable();
                 adapter.Fill(dataTable);
                  //添加數據
                 DataRow newRow = dataTable.NewRow();
                 newRow["id"] = "tesr";
                 newRow["name"] = "111";
                 dataTable.Rows.Add(newRow);
                 SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
                 adapter.Update(dataTable); //更新到數據庫
            }
            catch (SqlException ex)
            {
                 throw ex;
            }
      }
      

修改：

復制代碼代碼如下:

      using (SqlConnection connection = new SqlConnection(connectionString))
      {
            try
            {
                  SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
                  DataTable dataTable = new DataTable();
                  adapter.Fill(dataTable);
                  //修改數據
                 DataRow updateRow = dataTable.Rows[0];
                 updateRow["id"] = "update";
                 updateRow["name"] = "222";
                 SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
                 adapter.Update(dataTable); //更新到數據庫
            }
           catch (SqlException ex)
           {
                 throw ex;
           }
      }
      

刪除：

復制代碼代碼如下:

      using (SqlConnection connection = new SqlConnection(connectionString))
      {
            try
            {
                   SqlDataAdapter adapter = new SqlDataAdapter(selectStr, connection);
                   DataTable dataTable = new DataTable();
                   adapter.Fill(dataTable);
                   dataTable.Rows[0].Delete(); //刪除記錄
                   SqlCommandBuilder builder = new SqlCommandBuilder(adapter);
                   adapter.Update(dataTable); //更新到數據庫
             }
            catch (SqlException ex)
            {
                   throw ex;
            } 
      }