使用 OleDbParameter来写Access的更新没反应的解决办法
CodeSmith自定义模板生成的DAL，一开始生成的是MsSQL的。后来有需求，要转换成了Access。动软对Access生成支持不好，我手动替换了一次。然后把数据库从SQL导进Access。咋一看都没问题。
结果到了更新的部分，更新无任何变化：
#region Update /// <summary> /// 更新
/// </summary> /// <param name="dictionaryInfo">DictionaryInfo 实体对象</param> public void UpdateByPrimaryKey(DictionaryInfo dictionaryInfo) { StringBuilder strSql = new StringBuilder(); strSql.Append("update dt_Dictionary set "); strSql.Append("dict_CreateDate=@dict_CreateDate,"); strSql.Append("dict_Creator=@dict_Creator,"); strSql.Append("dict_IsVisible=@dict_IsVisible,"); strSql.Append("dict_Key=@dict_Key,"); strSql.Append("dict_Type=@dict_Type,"); strSql.Append("dict_Value=@dict_Value"); strSql.Append(" where dict_ID=@dict_ID"); OleDbParameter[] parameters = { new OleDbParameter("@dict_CreateDate", OleDbType.Date), new OleDbParameter("@dict_Creator", OleDbType.VarChar), new OleDbParameter("@dict_ID", OleDbType.Integer), new OleDbParameter("@dict_IsVisible", OleDbType.Boolean), new OleDbParameter("@dict_Key", OleDbType.Integer), new OleDbParameter("@dict_Type", OleDbType.Integer), new OleDbParameter("@dict_Value", OleDbType.VarChar) }; parameters[0].Value = dictionaryInfo.CreateDate; parameters[1].Value = dictionaryInfo.Creator; parameters[2].Value = dictionaryInfo.ID; parameters[3].Value = dictionaryInfo.IsVisible; parameters[4].Value = dictionaryInfo.Key; parameters[5].Value = dictionaryInfo.Type; parameters[6].Value = dictionaryInfo.Value; DbHelperSQL.ExecuteSql(strSql.ToString(), parameters); } #endregion
运行……，但是却没有效果——更新之后一刷新，又还原了！数据库里面根本没改动。
后来查资料才知道。是微软的一个BUG。在更新Access数据库时，如果使用OleDbParameter。那么OleDbParameter参数的的定义顺序必须和查询语句中参数出现的顺序一致！
这里：strSql.Append(" where dict_ID=@dict_ID"); 和 new OleDbParameter("@dict_ID", OleDbType.Integer), 顺序不一致导致!
所以，只要把参数定义的顺序换过来就行了。修改CodeSmith模板，自动生成以下代码执行成功：
#region Update /// <summary> /// 更新
/// </summary> /// <param name="dictionaryInfo">DictionaryInfo 实体对象</param> public void UpdateByPrimaryKey(DictionaryInfo dictionaryInfo) { StringBuilder strSql = new StringBuilder(); strSql.Append("update dt_Dictionary set "); strSql.Append("dict_CreateDate=@dict_CreateDate,"); strSql.Append("dict_Creator=@dict_Creator,"); strSql.Append("dict_IsVisible=@dict_IsVisible,"); strSql.Append("dict_Key=@dict_Key,"); strSql.Append("dict_Type=@dict_Type,"); strSql.Append("dict_Value=@dict_Value"); strSql.Append(" where dict_ID=@dict_ID "); OleDbParameter[] parameters = { new OleDbParameter("@dict_CreateDate", OleDbType.Date), new OleDbParameter("@dict_Creator", OleDbType.VarChar), new OleDbParameter("@dict_IsVisible", OleDbType.Boolean), new OleDbParameter("@dict_Key", OleDbType.Integer), new OleDbParameter("@dict_Type", OleDbType.Integer), new OleDbParameter("@dict_Value", OleDbType.VarChar), new OleDbParameter("@dict_ID", OleDbType.Integer) }; parameters[0].Value = dictionaryInfo.CreateDate; parameters[1].Value = dictionaryInfo.Creator; parameters[2].Value = dictionaryInfo.IsVisible; parameters[3].Value = dictionaryInfo.Key; parameters[4].Value = dictionaryInfo.Type; parameters[5].Value = dictionaryInfo.Value; parameters[6].Value = dictionaryInfo.ID; DbHelperSQL.ExecuteSql(strSql.ToString(), parameters); } #endregion