LINQ to SQL: updating without updating when "UpdateCheck = Never"

Question

I have an Account object that has all the fields in "UpdateCheck = Never" except one field. The field "ModifiedTime" uses "UpdateCheck = Always". The goal - concurrency checking should be based only on the "ModifiedTime" column.

For testing purposes, I supply the value "ModifiedTime", hard-coded in C # code. Therefore, there is no need to retrieve any value from the database for concurrency. However, the code will only update the database if I call the Refresh method. That seems weird. Any approach to avoid this?

Refer to the “Upgrade Without Request” section at http://msdn.microsoft.com/en-us/library/bb386929.aspx

Note. I am trying to avoid a SELECT statement without using Refresh

Generated SQL

SELECT [t0].[AccountNumber], [t0].[AccountType], [t0].[Duration], [t0].[DepositedAmount], [t0].[Prefernce], [t0].[Comment], [t0].[ModifiedTime] FROM [dbo].[Account] AS [t0] WHERE [t0].[AccountNumber] = @p0 -- @p0: Input Int (Size = -1; Prec = 0; Scale = 0) [1] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1 

Refresh Request

 UPDATE [dbo].[Account] SET [AccountType] = @p2, [Duration] = @p3 WHERE ([AccountNumber] = @p0) AND ([ModifiedTime] = @p1) -- @p0: Input Int (Size = -1; Prec = 0; Scale = 0) [1] -- @p1: Input DateTime (Size = -1; Prec = 0; Scale = 0) [6/25/2012 5:08:32 PM] -- @p2: Input NChar (Size = 10; Prec = 0; Scale = 0) [SUCESS] -- @p3: Input Int (Size = -1; Prec = 0; Scale = 0) [2] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1 

Table structure

 CREATE TABLE [dbo].[Account]( [AccountNumber] [int] NOT NULL, [AccountType] [nchar](10) NOT NULL, [Duration] [int] NOT NULL, [DepositedAmount] [int] NULL, [Prefernce] [int] NULL, [Comment] [nvarchar](50) NULL, [ModifiedTime] [datetime] NOT NULL, CONSTRAINT [PK_Account] PRIMARY KEY CLUSTERED ( [AccountNumber] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] 

C # code

  public virtual void UpdateChangesByAttach(T entity) { if (Context.GetTable<T>().GetOriginalEntityState(entity) == null) { //If it is not already attached Context.GetTable<T>().Attach(entity); Context.Refresh(System.Data.Linq.RefreshMode.KeepCurrentValues, entity); } } public void UpdateAccount() { //Used value from previous select DateTime previousDateTime = new DateTime(2012, 6, 25, 17, 8, 32, 677); RepositoryLayer.Account accEntity = new RepositoryLayer.Account(); accEntity.AccountNumber = 1; accEntity.AccountType = "SUCESS"; accEntity.ModifiedTime = previousDateTime; accEntity.Duration = 2; accountRepository.UpdateChangesByAttach(accEntity); accountRepository.SubmitChanges(); } 

Table data

READING:

• LINQ to SQL: how to update a single field without retrieving the entire object

• Update without first selecting data in LINQ 2 SQL?

• UPDATE SELECT in LINQ to SQL

• linq to sql update mulitple rows

• Default values ​​(from C # variables) Problem in updating LINQ to SQL

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Answer 1

Thanks @sgmoore. The values ​​to be updated are set after the Attach method. Now it works. What else needs to be improved?

Generated SQL

 UPDATE [dbo].[Account] SET [AccountType] = @p2, [Duration] = @p3, [ModifiedTime] = @p4 WHERE ([AccountNumber] = @p0) AND ([ModifiedTime] = @p1) -- @p0: Input Int (Size = -1; Prec = 0; Scale = 0) [1] -- @p1: Input DateTime (Size = -1; Prec = 0; Scale = 0) [6/25/2012 5:08:32 PM] -- @p2: Input NChar (Size = 10; Prec = 0; Scale = 0) [NEXT] -- @p3: Input Int (Size = -1; Prec = 0; Scale = 0) [4] -- @p4: Input DateTime (Size = -1; Prec = 0; Scale = 0) [6/26/2012 10:29:19 AM] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1 

THE CODE

  public void UpdateAccount() { //Used value from previous select DateTime previousDateTime = new DateTime(2012, 6, 25, 17, 8, 32, 677); RepositoryLayer.Account accEntity = new RepositoryLayer.Account(); accEntity.AccountNumber = 1; //Primary Key accEntity.ModifiedTime = previousDateTime; //Concurrency column accountRepository.UpdateChangesByAttach(accEntity); //Values to be modified after Attach accEntity.AccountType = "NEXT"; accEntity.ModifiedTime = DateTime.Now; accEntity.Duration = 4; accountRepository.SubmitChanges(); } public virtual void UpdateChangesByAttach(T entity) { if (Context.GetTable<T>().GetOriginalEntityState(entity) == null) { //If it is not already attached Context.GetTable<T>().Attach(entity); } }