自己开发轻量级ORM（二）

上一篇简单的对轻量级ORM开发开了个头。这篇主要聊下ORM框架的设计思路。

ORM本质上是对数据库操作的抽象。大体上我将其分为对数据结构的抽象和对执行方法的抽象。

我的ORM设计图：

ORM框架需要完成.net数据和数据库中数据的相互转换，以及对SQL语句中经典的增删改查操作的抽象封装。

封装方法代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.Common;
using Model.Entities;

namespace DAL.ErpSqlDAL.SqlFactory
{
    /// <summary>CRUD方法抽象
    /// 创建人：雷旭鹏(leo) 2014-1-13
    /// 联系方式：leixupeng823@163.com
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public abstract class OperateEntity<T>:ResolveEntity<T> where T :BaseEntity
    {
        public OperateEntity(DbCmd dbCmd, string entityName, Type entityType)
            : base(dbCmd, entityName, entityType)
        {
        }

        /// <summary>添加实体
        /// </summary>
        /// <param name="entityList">要添加的内容</param>
        /// <returns></returns>
        public virtual object AddEntity(IList<T> entityList)
        {
            try
            {
                base.SourceEntity = entityList;
                base.ConditionEntity = null;
                base.OperateType = OperateType.INSERT;
                base.EntityToSql();

                string strSql = base.CommandString;

                return DBHelper.ExecuteScalar(dbCmd.Cmd, CommandType.Text, strSql, base.Parameters.ToArray());
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
        /// <summary>修改实体,要修改的内容和条件一一对应
        /// </summary>
        /// <param name="entityList">要修改的内容</param>
        /// <param name="conditionList">条件</param>
        /// <returns></returns>
        public virtual int ModEntity(IList<T> entityList, IList<T> conditionList)
        {
            try
            {
                base.SourceEntity = entityList;
                base.ConditionEntity = conditionList;
                base.OperateType = OperateType.UPDATE;

                base.EntityToSql();
                string strSql = base.CommandString;
                return DBHelper.ExecuteNonQuery(dbCmd.Cmd, CommandType.Text, strSql, base.Parameters.ToArray());
            }
            catch
            {
                throw;
            }
        }
        /// <summary>根据主键修改实体 
        /// </summary>
        /// <param name="entityList">要修改的内容和包含主键值的实体</param>
        /// <returns></returns>
        public virtual int ModEntity(IList<T> entityList)
        {
            try
            {
                IList<T> cndEntity = new List<T>();
                CreatePKConditionFromSourceEntity(entityList, cndEntity);
                return ModEntity(entityList, cndEntity);
            }
            catch
            {
                throw;
            }
        }
        /// <summary>删除实体 
        /// </summary>
        /// <param name="conditionList">删除的条件</param>
        /// <returns></returns>
        public virtual int DelEntity(IList<T> conditionList)
        {
            try
            {
                base.SourceEntity = conditionList;
                base.ConditionEntity = conditionList;
                base.OperateType = OperateType.DELETE;

                base.EntityToSql();
                string strSql = base.CommandString;
                return DBHelper.ExecuteNonQuery(dbCmd.Cmd, CommandType.Text, strSql, base.Parameters.ToArray());
            }
            catch
            {
                throw;
            }
        }
        /// <summary>得到实体 
        /// </summary>
        /// <param name="condition">查询条件</param>
        /// <returns></returns>
        public virtual IList<T> GetEntity(T condition)
        {
            try
            {
                if (condition != null)
                {
                    IList<T> coditionLists = new List<T>();
                    coditionLists.Add(condition);

                    base.ConditionEntity = coditionLists;
                    base.SourceEntity = coditionLists;
                }
                base.OperateType = OperateType.SELECT;

                base.EntityToSql();
                string strSql = base.CommandString;
                return base.DateSetToEntity(DBHelper.GetDataSet(dbCmd.Adapter, dbCmd.Cmd, CommandType.Text, strSql, base.Parameters.ToArray()));
            }
            catch
            {
                throw;
            }
        }
        /// <summary>得到一个值 
        /// </summary>
        /// <param name="conditionList">查询条件</param>
        /// <returns></returns>
        public virtual Object GetValue(T conditionList)
        {
            try
            {
                IList<T> coditionLists = new List<T>();
                coditionLists.Add(conditionList);

                base.SourceEntity = coditionLists;
                base.ConditionEntity = coditionLists;
                base.OperateType = OperateType.SELECT;

                base.EntityToSql();
                string strSql = base.CommandString;
                return DBHelper.ExecuteScalar(dbCmd.Cmd, CommandType.Text, strSql, base.Parameters.ToArray());
            }
            catch
            {
                throw;
            }
        }

        //exce by sql
        /// <summary>执行存储过程得到一个值 
        /// </summary>
        /// <param name="sqlStr">存储过程的名称</param>
        /// <param name="Parameters">参数</param>
        /// <returns></returns>
        protected virtual Object GetValueByProc(string sqlStr, params DbParameter[] Parameters)
        {
            try
            {
                return DBHelper.ExecuteScalar(dbCmd.Cmd, CommandType.StoredProcedure, sqlStr, Parameters);
            }
            catch
            {
                throw;
            }
        }
        /// <summary>执行SQL语句得到一个值 
        /// </summary>
        /// <param name="sqlStr">SQL语句</param>
        /// <param name="Parameters">参数</param>
        /// <returns></returns>
        protected virtual Object GetValueBySql(string sqlStr, params DbParameter[] Parameters)
        {
            try
            {
                return DBHelper.ExecuteScalar(dbCmd.Cmd, CommandType.Text, sqlStr, Parameters);
            }
            catch
            {
                throw;
            }
        }
        /// <summary>执行SQL，返回受影响的函数
        /// </summary>
        /// <param name="sqlStr">存储过程的名称</param>
        /// <param name="Parameters">参数</param>
        /// <returns></returns>
        protected virtual int ExecuteSql(string sqlStr, params DbParameter[] Parameters)
        {
            try
            {
                return DBHelper.ExecuteNonQuery(dbCmd.Cmd, CommandType.Text, sqlStr, Parameters);
            }
            catch
            {
                throw;
            }
        }
        /// <summary>执行存储过程,返回受影响的函数
        /// </summary>
        /// <param name="sqlStr">存储过程的名称</param>
        /// <param name="Parameters">参数</param>
        /// <returns></returns>
        protected virtual int ExecuteProc(string sqlStr, params DbParameter[] Parameters)
        {
            try
            {
                return DBHelper.ExecuteNonQuery(dbCmd.Cmd, CommandType.StoredProcedure, sqlStr, Parameters);
            }
            catch
            {
                throw;
            }
        }

        /// <summary>通过SQL语句得到实体 
        /// </summary>
        /// <param name="sqlStr">SQL</param>
        /// <returns></returns>
        protected virtual IList<T> GetEntityBySql(string sqlStr)
        {
            try
            {
                return base.DateSetToEntity(DBHelper.GetDataSet(dbCmd.Adapter, dbCmd.Cmd, CommandType.Text, sqlStr, null));
            }
            catch
            {
                throw;
            }
        }
        /// <summary>通过SQL语句得到DataSet 
        /// </summary>
        /// <param name="sqlStr">SQL</param>
        /// <returns></returns>
        protected virtual DataSet GetDataSetBySql(string sqlStr)
        {
            try
            {
                return DBHelper.GetDataSet(dbCmd.Adapter, dbCmd.Cmd, CommandType.Text, sqlStr, null);
            }
            catch
            {
                throw;
            }
        }
        /// <summary>通过SQL语句得到实体 
        /// </summary>
        /// <param name="sqlStr">SQL</param>
        /// <param name="Parameters">参数</param>
        /// <returns></returns>
        protected virtual IList<T> GetEntityBySql(string sqlStr, params DbParameter[] Parameters)
        {
            try
            {
                return base.DateSetToEntity(DBHelper.GetDataSet(dbCmd.Adapter, dbCmd.Cmd, CommandType.Text, sqlStr, Parameters));
            }
            catch
            {
                throw;
            }
        }
        /// <summary>通过存储过程，语句得到实体 
        /// </summary>
        /// <param name="sqlStr">SQL</param>
        /// <param name="Parameters">参数</param>
        /// <returns></returns>
        protected virtual IList<T> GetEntityByProc(string sqlStr, params DbParameter[] Parameters)
        {
            try
            {
                return base.DateSetToEntity(DBHelper.GetDataSet(dbCmd.Adapter, dbCmd.Cmd, CommandType.StoredProcedure, sqlStr, Parameters));
            }
            catch
            {
                throw;
            }
        }
    }
}

下一篇将讲下从代码上如何实现上面的设计图。