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This article will explain in detail how to use the Linq Setting field for you. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Linq Setting field storage

This article introduces the Linq Setting field, the people who have used Linq know its benefits, such as designing a table such as student information table, such as learning hobbies, personality, life experience and other fields, I believe that the previous design concept is to design three fields into three Nvarchar (8000) type fields, or some of them are designed as Text type fields, these designs are all right, but they are not very good.

Now that you have Linq, you can put all three fields in the Linq Setting field (note that the name of the field must be Setting), and the data can be stored by setting the Linq Setting field to the image type. How to use C # syntax to store it? We'll talk about it later. The disadvantage of using Setting field to store data is that when doing conditional query, using Setting as query condition is somewhat complex, and generally does not make conditional query.

Private string _ hotelDescription = string.Empty;// 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);}

Union in Linq (recursive query, query all nodes under the parent node)

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})

The combination of subqueries of Join and Company in Linq

Var roles = from aa in (

From an 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

The left join query in Linq uses the DefaultIfEmpty () syntax

Var svcUser = from an 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)

}

This is the end of the article on "how to use the Linq Setting field". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.

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