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Linq Setting字段存储
本文介绍Linq Setting字段,这个用过Linq的人都知道它的好处,如在设计一张表如学生信息表,如学习爱好,性格,生活经历等这些字段,相信大家在以前的设计理念是将三个字段设计成三个 Nvarchar(8000)类型字段,或者有些设计成 Text 类型字段,这些设计都没错,但都不是很好。
现在有 Linq,可以将这三个字段都放在Linq Setting字段中(注意这里,字段的名称必须为Setting),Linq Setting字段设置成 image 类型即可实现数据的存储。如何用C#语法来存储呢?????以后有空再说。用Setting字段存储的数据,缺点是做条件查询时,用Setting作为查询条件就有些复杂了,一般不作条件查询。
private string _hotelDescription = string.Empty;//兴趣 public string HotelDescription { get { return _hotelDescription; } set { _hotelDescription = value; } } partial void OnLoaded() { byte[] bytes = Setting.ToArray(); CSetting setting = new CSetting(bytes); load(setting); } partial void OnValidate(System.Data.Linq.ChangeAction action) { CSetting setting = new CSetting(); save(setting); byte[] bytes = setting.ToByteArray(); Setting = new Binary(bytes); } private void save(CSetting setting) { setting.Set("desc", _hotelDescription); } private void load(CSetting setting) { _hotelDescription = setting.Get("desc", string.Empty); }
Linq中的Union(递归查询,查询父节点下所有节点)
var query = (from item1 in dc.SysOrganization where (item1.FatherSysOrganizationID == orgId) && item1.IsDel == false select new SysOrganizationInfo { SysOrganizationID =item1.SysOrganizationID,Name=item1.Name,Code=item1.Code,BaseProvinceID=(int)item1.BaseProvinceID,BaseCityID=(int)item1.BaseCityID}) .Union( from item2 in dc.SysOrganization join item3 in dc.SysOrganization on item2.FatherSysOrganizationID equals item3.SysOrganizationID where (item2.SysOrganizationID == orgId) && item2.IsDel == false select new SysOrganizationInfo { SysOrganizationID = item2.SysOrganizationID, Name = item2.Name, Code = item2.Code, BaseProvinceID = (int)item2.BaseProvinceID, BaseCityID = (int)item2.BaseCityID });
Linq中Join连所子查询结合
var roles = from aa in( from a in dc.SysOrganizationRoleUser join b in dc.SysOrganizationRole on a.SysRoleID equals b.SysRoleID join c in dc.SysOrganizationRoleFunctionItem on b.SysRoleID equals c.SysRoleID join d in dc.SysFunctionItem on c.SysFunctionItemID equals d.SysFunctionItemID join d2 in dc.SysFunctionItem on c.SysFunctionItemID equals d2.SysFunctionItemID where a.SysUserID == userID select d) from bb in dc.SysFunctionItem where aa.SysFunctionItemID == bb.SysFunctionItemID || aa.FatherFunctionItemID == bb.SysFunctionItemID select bb;
Linq中的左连接查询用到 DefaultIfEmpty() 语法
var svcUser = from a in hdc.SysServiceCenterUser join b in hdc.SysServiceCenter on a.SysServiceCenterID equals b.SysServiceCenterID join c in hdc.SysServicePositionUser on a.SysUserID equals c.SysUserID into pous from c in pous.DefaultIfEmpty() join d in hdc.SysServiceCenterPosition on c.SysServicePositionID equals d.SysServicePositionID into po from d in po.DefaultIfEmpty() where (_SysServiceCenterID == 0 ? true : a.SysServiceCenterID == _SysServiceCenterID) && (_SysServicePositionID == 0 ? true : (from w in hdc.SysServicePositionUser where w.SysServicePositionID == _SysServicePositionID select w.SysUserID).Contains(a.SysUserID)) && (_Name == null || _Name.Trim() == "" ? true : a.FullName.Contains(_Name)) && (_Code == null || _Code.Trim() == "" ? true : a.Code == _Code) select new Svc { _SysUserID = (a.SysUserID == null ? 0 : a.SysUserID), _SysServiceCenterID = (a.SysServiceCenterID==null?0:(int)a.SysServiceCenterID), //_SysServicePositionID = (int)c.SysServicePositionID, _SvcName = b.Name, //_PositionName = d.Name, _LoginName = a.LoginName, _FullName = a.FullName, _Code = (a.Code==null?"":a.Code) };
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