C # operation of the database (CRUD)

C # operation of the database (CRUD)

1, the configuration in the web.config file []

<connectionStrings>
    <add name="sqlConnection" connectionString="Data Source=服务器;Initial Catalog=数据库名称;Persist Security Info=True;User ID=用户名;Password=密码" providerName="System.Data.SqlClient"/>
  </connectionStrings>

2, the connection string []

private static readonly string StrCon = ConfigurationManager.ConnectionStrings["sqlConnection"].ToString();

3, query data [method]

 

/// <summary>
        /// 查询数据
        /// </summary>
        /// <param name="sqlStr">查询语句</param>
        /// <param name="parameter">参数</param>
        /// <returns></returns>
        public static DataTable QueryData(string sqlStr,params SqlParameter [] parameter) {
            try
            {
                using (SqlConnection conn = new SqlConnection())
                {
                    conn.Open();
                    SqlCommand cmd = new SqlCommand(sqlStr, conn);
                    DataSet dt = new DataSet();
                    SqlDataAdapter adapter = new SqlDataAdapter();
                    cmd.Parameters.AddRange(parameter);
                    adapter.SelectCommand = cmd;
                    adapter.Fill(dt);
                    conn.Close();
                    return dt.Tables[0];
                }
            }
            catch (Exception ex)
            {
                throw new ApplicationException("查询数据异常"+ex.Message);
            }
        }

 

4, updating data [Method]

 

/// <summary>
        /// 更新数据
        /// </summary>
        /// <param name="sqlStr">更新语句</param>
        /// <param name="parameter">参数</param>
        /// <returns></returns>
        public static bool UpdateData(string sqlStr, params SqlParameter[] parameter) {
            try
            {
                using (SqlConnection conn = new SqlConnection())
                {
                    conn.Open();
                    SqlCommand cmd = new SqlCommand(sqlStr,conn);
                    cmd.Parameters.AddRange(parameter);
                    var row=cmd.ExecuteNonQuery();
                    conn.Close();
                    if (row>0)
                    {
                        return true;
                    }
                    return false;
                }
            }
            catch (Exception ex)
            {
                throw new ApplicationException("更新数据异常"+ex.Message) ;
            }
        }

 

5. Delete Data Method]

 

/// <summary>
        /// 删除数据
        /// </summary>
        /// <param name="sqlStr">删除语句</param>
        /// <param name="parameter">参数</param>
        /// <returns></returns>
        public static bool DeleteData(string sqlStr,params SqlParameter[] parameter) {
            try
            {
                using (SqlConnection conn=new SqlConnection())
                {
                    conn.Open();
                    SqlCommand cmd = new SqlCommand(sqlStr,conn);
                    cmd.Parameters.AddRange(parameter);
                    var row = cmd.ExecuteNonQuery();
                    conn.Close();
                    if (row>0)
                    {
                        return true;
                    }
                    return false;
                }
            }
            catch (Exception ex)
            {
                throw new ApplicationException("删除数据异常"+ex.Message);
            }
        }

 

6, adding data [Method]

 

/// <summary>
        /// 删除数据
        /// </summary>
        /// <param name="sqlStr">删除语句</param>
        /// <param name="parameter">参数</param>
        /// <returns></returns>
        public static bool AddData(string sqlStr,params SqlParameter[] parameter) {
            try
            {
                using (SqlConnection conn = new SqlConnection())
                {
                    conn.Open();
                    SqlCommand cmd = new SqlCommand(sqlStr,conn);
                    cmd.Parameters.AddRange(parameter);
                    var row = cmd.ExecuteNonQuery();
                    conn.Close();
                    if (row>0)
                    {
                        return true;
                    }
                    return false;
                }
            }
            catch (Exception ex)
            {
                throw new ApplicationException("添加数据异常"+ex.Message);
            }
        }

 

7, write a method call query data [method], the other three method calls similar to this

public DataTable GetInfo(string id) {
            var sqlStr = "select * from Student where id=@id";
            DataTable table = SqlHelper.QueryData(sqlStr, new System.Data.SqlClient.SqlParameter[] { new System.Data.SqlClient.SqlParameter("@id",id) });
            return table;
        }