给实体类 写个---通用数据库操作类

Question

本帖最后由 xiangjianlin 于 2010-12-06 12:41:59 编辑

Answer 1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Configuration;
using System.Data;
using System.Data.OleDb;namespace   XXX
{
    /// <summary>
    /// OLEDB查询辅助类
    /// </summary>
    public abstract class OleDbHelper
    {
        //数据库连接字符串
        public static readonly string ConnectionString = ConfigurationManager.AppSettings["OLEDBConnStr"];        #region 公共方法        /// <summary>
        /// 执行 SQL 语句（如 INSERT、DELETE、UPDATE 和 SET 语句等命令）。
        /// </summary>
        /// <param name="connectionString">连接字符串</param>
        /// <param name="cmdType">指定如何解释命令</param>
        /// <param name="cmdText">要对数据源执行的 SQL 语句或存储过程</param>
        /// <param name="commandParameters">命令的参数</param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {            OleDbCommand cmd = new OleDbCommand();            using (OleDbConnection conn = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                int val = cmd.ExecuteNonQuery();
                cmd.Parameters.Clear();
                return val;
            }
        }        /// <summary>
        /// 执行 SQL 语句（如 INSERT、DELETE、UPDATE 和 SET 语句等命令）。
        /// </summary>
        /// <param name="connection">到数据源的连接</param>
        /// <param name="cmdType">指定如何解释命令</param>
        /// <param name="cmdText">要对数据源执行的 SQL 语句或存储过程</param>
        /// <param name="commandParameters">命令的参数</param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {            OleDbCommand cmd = new OleDbCommand();            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }        /// <summary>
        /// 执行指定的事务。
        /// </summary>
        /// <param name="trans">要在数据源执行的 SQL 事务</param>
        /// <param name="cmdType">指定如何解释命令</param>
        /// <param name="cmdText">要对数据源执行的 SQL 语句或存储过程</param>
        /// <param name="commandParameters">命令的参数</param>
        /// <returns>受影响的行数</returns>
        public static int ExecuteNonQuery(OleDbTransaction trans, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
            int val = cmd.ExecuteNonQuery();
            cmd.Parameters.Clear();
            return val;
        }
        /// <summary>
        /// 获取数据记录读取对象
        /// </summary>
        /// <param name="connectionString">连接字符串</param>
        /// <param name="cmdType">指定如何解释命令</param>
        /// <param name="cmdText">要对数据源执行的 SQL 语句或存储过程</param>
        /// <param name="commandParameters">命令的参数</param>
        /// <returns>数据记录读取对象</returns>
        public static OleDbDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();
            OleDbConnection conn = new OleDbConnection(connectionString);            // we use a try/catch here because if the method throws an exception we want to 
            // close the connection throw code, because no datareader will exist, hence the 
            // commandBehaviour.CloseConnection will not work
            try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
                OleDbDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return rdr;
            }
            catch
            {
                conn.Close();
                throw;
            }
        }        /// <summary>
        /// 从数据源中检索单个值
        /// </summary>
        /// <param name="connectionString">连接字符串</param>
        /// <param name="cmdType">指定如何解释命令</param>
        /// <param name="cmdText">要对数据源执行的 SQL 语句或存储过程</param>
        /// <param name="commandParameters">命令的参数</param>
        /// <returns>检索的值</returns>
        public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {
            OleDbCommand cmd = new OleDbCommand();            using (OleDbConnection connection = new OleDbConnection(connectionString))
            {
                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
                object val = cmd.ExecuteScalar();
                cmd.Parameters.Clear();
                return val;
            }
        }        /// <summary>
        /// 从数据源中检索单个值
        /// </summary>
        /// <param name="connection">到数据源的连接</param>
        /// <param name="cmdType">指定如何解释命令</param>
        /// <param name="cmdText">要对数据源执行的 SQL 语句或存储过程</param>
        /// <param name="commandParameters">命令的参数</param>
        /// <returns>检索的值</returns>
        public static object ExecuteScalar(OleDbConnection connection, CommandType cmdType, string cmdText, params OleDbParameter[] commandParameters)
        {            OleDbCommand cmd = new OleDbCommand();            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
            object val = cmd.ExecuteScalar();
            cmd.Parameters.Clear();
            return val;
        }        #endregion        #region 私有方法        /// <summary>
        /// 准备一个执行的命令
        /// </summary>
        /// <param name="cmd">OleDb命令对象</param>
        /// <param name="conn">OleDb连接对象</param>
        /// <param name="trans">Sql事务对象</param>
        /// <param name="cmdType">命令类型，如：存储过程或文本</param>
        /// <param name="cmdText">命令文本，如：SQL语句</param>
        /// <param name="cmdParms">命令中使用的OleDb参数</param>
        private static void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, CommandType cmdType, string cmdText, OleDbParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();            cmd.Connection = conn;
            cmd.CommandText = cmdText;            if (trans != null)
                cmd.Transaction = trans;            cmd.CommandType = cmdType;            if (cmdParms != null)
            {
                foreach (OleDbParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
            }
        }        #endregion    }
}

Answer 2

很多
看看微软企业库
LINQ