entityservice.cs

实现数据库中实体到类的动态映射,通过映射可方便的实现数据库记录的增删改查等操作.

using System;
using System.Xml;
using System.Collections;
using System.Data;

namespace EntityMapping
{
	/// <summary>
	/// EntityMapping 的摘要说明。
	/// </summary>
	public class EntityService
	{
		private EntityMapping.Entity ent_ReturnEntity = new Entity();
		private DataAccessObject dao_Temp;
		private EntityMapping.EntitySet eSet = new EntitySet();
		/// <summary>
		/// 获取数据访问对象
		/// </summary>
		public EntityService()
		{
			try
			{
				if(this.dao_Temp == null)
				{
					System.Xml.XmlDocument xml_Doc = new XmlDocument();
					//加载XML文件到文档对象中
					xml_Doc.Load("d:\\MapConfig.xml");
					//获取相应的链接字符串
					System.Xml.XmlNodeList xmlNS= xml_Doc.GetElementsByTagName("DataLink");

					string str_Con =xmlNS.Item(0).ChildNodes[0].Attributes["Link"].Value.ToString();
					this.dao_Temp = new DataAccessObject(EntityMapping.DataType.Oracle,str_Con);
				}
			}
			catch(Exception exp)
			{
				throw new Exception(exp.ToString());
			}
			//
			// TODO: 在此处添加构造函数逻辑
			//
		}
		/// <summary>
		/// 根据实体信息,查询相应字段信息
		/// </summary>
		/// <param name="ent_Temp">实体</param>
		/// <returns>返回查询得到的实体</returns>
		public Entity GetEntity(Entity ent_Temp)
		{
			string str_Sql = "Select * from " + ent_Temp.TableName ;
			if(ent_Temp.Attribute.Count > 0)
			{
				str_Sql = str_Sql + " where ";
				IDictionaryEnumerator de_Temp = ent_Temp.Attribute.GetEnumerator();
				//遍历整个实体的属性,以组合成相应的查询语句
				while(de_Temp.MoveNext())
				{
						str_Sql = str_Sql + " " + de_Temp.Key.ToString() + de_Temp.Value.ToString();
				}
			}

			this.GetEntityBySql(str_Sql);

			return null;
		}
		/// <summary>
		/// 根据SQL语句查询实体
		/// </summary>
		/// <param name="str_Sql">Sql语句</param>
		/// <returns>返回查询得到的实体</returns>
		public Entity GetEntityBySql(string str_Sql)
		{
			DataSet ds_Temp = new  DataSet();

			try
			{
				ds_Temp = this.dao_Temp.QueryBySql(str_Sql);
			}
			catch(Exception exp)
			{
				throw new Exception(exp.ToString());
			}
			if(ds_Temp.Tables[0].Rows.Count > 0)
			ent_ReturnEntity.FillData(ds_Temp.Tables[0],0);
			
			return ent_ReturnEntity;
		}
		/// <summary>
		/// 查询得到实体集
		/// </summary>
		/// <param name="str_Sql">查询的SQL语句</param>
		/// <returns>返回查询结果的实体集合</returns>
		public EntitySet GetEntitySetBySql(string str_Sql)
		{
			DataSet ds_Temp = new  DataSet();

			try
			{
				ds_Temp = this.dao_Temp.QueryBySql(str_Sql);
			}
			catch(Exception exp)
			{
				throw new Exception(exp.ToString());
			}
			this.eSet.DataSource = ds_Temp;
			this.eSet.MappingTableName = ds_Temp.Tables[0].TableName;
			
			return eSet;
			
		}

		/// <summary>
		/// 根据实体信息生成SQL语句查询获得实体集合
		/// </summary>
		/// <param name="ent_Temp"></param>
		/// <returns></returns>
		public EntitySet GetEntitySet(Entity ent_Temp)
		{
			string str_Sql = "Select * from " + ent_Temp.TableName ;
			if(ent_Temp.Attribute.Count > 0)
			{
				str_Sql = str_Sql + " where ";
				IDictionaryEnumerator de_Temp = ent_Temp.Attribute.GetEnumerator();
			
				while(de_Temp.MoveNext())
				{
					str_Sql = str_Sql + " " + de_Temp.Key.ToString() + de_Temp.Value.ToString();
					
				}
			}
			return GetEntitySetBySql(str_Sql);
			
		}

		/// <summary>
		/// 插入一个新的实体数据到数据库
		/// </summary>
		/// <param name="ent_Temp">要插入的实体数据</param>
		/// <returns>返回受影响记录的条数</returns>
		public int InsertNewEntity(Entity ent_Temp)
		{
			string str_Sql = "insert into " + ent_Temp.TableName ;
			if(ent_Temp.Attribute.Count > 0)
			{
				str_Sql = str_Sql + " ";
				IDictionaryEnumerator de_Temp = ent_Temp.Attribute.GetEnumerator();
				string Field = "(" ,Value = "(";
				while(de_Temp.MoveNext())
				{
					Field =  Field + de_Temp.Key.ToString() + ",";
					Value = Value +  de_Temp.Value.ToString() + ",";
				}
				Field = Field.Substring(0,Field.LastIndexOf(","));
				Value = Value.Substring(0,Value.LastIndexOf(","));

				Field = Field + ")";
				Value = Value + ")";
				str_Sql = str_Sql + Field + " values" + Value;
			}
			
			this.ExcuteBySql(str_Sql);
			return 0;
		}
		
		/// <summary>
		/// 更新一个实体
		/// </summary>
		/// <param name="ent_Temp">更新的实体内容</param>
		/// <returns>返回受影响记录的条数</returns>
		public int UpdateEntity(Entity ent_Temp)
		{
			string str_Sql = "Update " + ent_Temp.TableName ;
			string str_Where = "where 1=1 " ;
			if(this.dao_Temp.DBType == EntityMapping.DataType.Oracle)
			{
				string str_PK = "select col.column_name from user_constraints con,  user_cons_columns col"
					+ " where con.constraint_name = col.constraint_name and con.constraint_type='P'" 
					+ " and col.table_name ='" + ent_Temp.TableName.ToUpper() + "'";
				System.Data.DataSet ds_Temp = this.dao_Temp.QueryBySql(str_PK);
				if(ds_Temp.Tables[0].Rows.Count > 0)
				{
					for(int i = 0 ; i < ds_Temp.Tables[0].Rows.Count ; i++)
					{
						str_PK = ds_Temp.Tables[0].Rows[0]["column_name"].ToString();
						
						if((!ent_Temp.Attribute.ContainsKey(str_PK)) & (ent_Temp.Attribute[str_PK] == null))
						{
							throw new Exception("更新记录时,必须指明主键字段的值");
						}
						else
						{
							str_Where = str_Where + " and " +  str_PK + "=" + ent_Temp.Attribute[str_PK];
							ent_Temp.Attribute.Remove(str_PK);
						}
						
					}
				}
			}

			if(ent_Temp.Attribute.Count > 0)
			{
				str_Sql = str_Sql + " ";
				IDictionaryEnumerator de_Temp = ent_Temp.Attribute.GetEnumerator();
				str_Sql = str_Sql + "set ";
				while(de_Temp.MoveNext())
				{

					str_Sql = str_Sql + de_Temp.Key.ToString() + "="  + de_Temp.Value.ToString();
				}
				
			}
			
			str_Sql = str_Sql + " " + str_Where;
			
			return this.ExcuteBySql(str_Sql);

			
		}
		
		/// <summary>
		/// 根据SQL语句向数据库中操作数据
		/// </summary>
		/// <param name="str_Sql">SQL语句</param>
		/// <returns>返回受影响的记录条数</returns>
		public int ExcuteBySql(string str_Sql)
		{
			
			return this.dao_Temp.ExcuteBySql(str_Sql);
		}

		/// <summary>
		/// 从数据库中删除实体数据
		/// </summary>
		/// <param name="ent_Temp">删除的实体数据</param>
		/// <returns>返回受影响的记录条数</returns>
		public int DeleteEntity(Entity ent_Temp)
		{
			string str_Sql = "delete " + ent_Temp.TableName ;
			string str_Where = "where 1=1 " ;
			if(this.dao_Temp.DBType == EntityMapping.DataType.Oracle)
			{
				string str_PK = "select col.column_name from user_constraints con,  user_cons_columns col"
					+ " where con.constraint_name = col.constraint_name and con.constraint_type='P'" 
					+ " and col.table_name ='" + ent_Temp.TableName.ToUpper() + "'";
				System.Data.DataSet ds_Temp = this.dao_Temp.QueryBySql(str_PK);
				if(ds_Temp.Tables[0].Rows.Count > 0)
				{
					for(int i = 0 ; i < ds_Temp.Tables[0].Rows.Count ; i++)
					{
						str_PK = ds_Temp.Tables[0].Rows[0]["column_name"].ToString();
						
						if((!ent_Temp.Attribute.ContainsKey(str_PK)) & (ent_Temp.Attribute[str_PK] == null))
						{
							throw new Exception("删除记录时,必须指明主键字段的值");
						}
						else
						{
							str_Where = str_Where + " and " +  str_PK + "=" + ent_Temp.Attribute[str_PK];
							ent_Temp.Attribute.Remove(str_PK);
						}
						
					}
				}
			}
			str_Sql = str_Sql + " " + str_Where;
			return this.ExcuteBySql(str_Sql);
		}
//		/// <summary>
//		/// 删除记录集合(从数据库中删除多条记录)
//		/// </summary>
//		/// <param name="entSet">实体集合</param>
//		/// <returns>返回受影响的记录的条数</returns>
//		public int DeleteEntitySet(EntitySet entSet)
//		{
//			return 0;
//		}
	}
}