在http://blog.csdn.net/jacky4955/article/details/9138411(http://blog.csdn.net/jacky4955/article/details/9138411)裏面,是對操作底層的封裝,但對於偶來說,其實並不滿意。因爲操作還是顯得太過繁瑣,每一次都得去實現基礎的幾個方法,即使他的代碼很少,這個也是一種浪費,作爲一個攻城師,堅決不做碼農,不去重複同樣的工作。於是針對DAL的數據操作做了一個父類。
上代碼:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;
using System.Data.Objects.DataClasses;
using System.Reflection;
namespace NOAS.PublicOpinionMonitor.Access.Common
{
public class AccessBase<T> where T : class
{
private string _strTableName;
private string _ColumsName;
private string _PrimaryKey;
private Type _PrimaryKeyType;
public AccessBase(string PrimaryKey = "", string strTableName = "", string ColumsName = "")
{
Type t = typeof(T);
if (string.IsNullOrEmpty(strTableName))
{
strTableName = t.Name; //GetType(t).ToString();
}
_strTableName = strTableName;
if (string.IsNullOrEmpty(ColumsName))
{
_ColumsName = " * ";
}
if (string.IsNullOrEmpty(PrimaryKey))
{
PropertyInfo[] infos = t.GetProperties();
_PrimaryKey = getPrimaryKey(infos);
}
}
/// <summary>
/// 獲取主鍵,此方式只適用於edmx數據表結構
/// </summary>
/// <param name="infos"></param>
/// <returns></returns>
private string getPrimaryKey(PropertyInfo[] infos)
{
string columnName = string.Empty;
foreach (PropertyInfo propertyInfo in infos)
{
object[] customInfos = propertyInfo.GetCustomAttributes(typeof(EdmScalarPropertyAttribute), true);
if (customInfos == null
|| customInfos.Length == 0)
return string.Empty;
EdmScalarPropertyAttribute limit = customInfos.GetValue(0) as EdmScalarPropertyAttribute;
if (limit.EntityKeyProperty)
{
_PrimaryKeyType = propertyInfo.PropertyType;
return columnName = propertyInfo.Name;
}
}
return columnName;
}
/// <summary>
/// 執行數據庫操作基礎類方法
/// </summary>
protected DataCommon Data = new DataCommon();
/// <summary>
/// 增加單個實體
/// </summary>
/// <param name="t"></param>
public virtual void addEntity(T t)
{
Data.InsertEntity<T>(t);
}
public virtual T getSingleEntity(Expression<Func<T, bool>> query)
{
return Data.GetSingleEntity<T>(query);
}
public virtual T getSingleEntity(object PrimaryKeyId)
{
StringBuilder strWhere = new StringBuilder();
switch (_PrimaryKeyType.Name.ToLower())
{
case "int16":
case "int32":
case "int64":
case "int":
case "decimal":
case "double":
case "float":
case "short":
strWhere.AppendFormat(" {0}={1}", _PrimaryKey, PrimaryKeyId);
break;
case "bool":
case "boolean":
if ((bool)PrimaryKeyId)
{ strWhere.AppendFormat(" {0}=1", _PrimaryKey);}
else
{ strWhere.AppendFormat(" {0}=0", _PrimaryKey); }
break;
default:
strWhere.AppendFormat(" {0}='{1}'", _PrimaryKey, PrimaryKeyId);
break;
}
return getListByWhere(strWhere.ToString()).FirstOrDefault();
}
/// <summary>
/// 修改單個實體
/// </summary>
/// <param name="t"></param>
public virtual void updateEntity(T t)
{
Data.Update<T>(t);
}
/// <summary>
/// 根據條件刪除信息
/// </summary>
/// <param name="query">條件</param>
public virtual void deleteEntity(Expression<Func<T, bool>> query)
{
Data.DeleteEntitys<T>(query);
}
/// <summary>
/// 根據條件獲取相關監測信息表
/// </summary>
/// <param name="strWhere">Where條件</param>
/// <returns>數據集合</returns>
protected virtual List<T> getListByWhere(string strWhere)
{
StringBuilder strSql = new StringBuilder();
strSql.AppendFormat("select {1} from {0}", _strTableName, _ColumsName);
if (!string.IsNullOrEmpty(strWhere))
{
strSql.AppendFormat(" where {0}", strWhere);
}
return Data.ExecuteQuery<T>(strSql.ToString()).ToList();
}
/// <summary>
/// 獲取最大主鍵
/// </summary>
/// <returns></returns>
protected virtual int? getMaxPrimaryKey()
{
StringBuilder strSql = new StringBuilder();
strSql.AppendFormat("select max({1}) from {0}", _strTableName, _PrimaryKey);
return Data.ExecuteQuery<int>(strSql.ToString()).FirstOrDefault();
}
}
}
這樣繼承的子類,就自動擁有了增刪改查的基礎方法。