Databases
StackOverflow2013
Postsdbo
PODefault Values (of C# variables) Issue in LINQ to SQL Update
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PODefault Values (of C# variables) Issue in LINQ to SQL Update
    primarykey
    data
    text
    <p>I have the following code for updating Account table with LINQ to SQL. AccountNumber is the primary key column. The only value which need to be updated is AccountType; however the Duration also gets updated with zero (default value for int). How can we avoid this unnecessary overwrite?</p> <p>Note: I am using <strong>Attach</strong> method</p> <p>Note: I understand the reason for this behavior. "The DataContext cannot distinguish between a field with an assigned value of zero and one that is merely unassigned.". I am looking for a solution to overcome this.</p> <pre><code>[global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_Duration", DbType="Int NOT NULL" public int Duration </code></pre> <p>Table DATA</p> <p><img src="https://i.stack.imgur.com/TpQS7.jpg" alt="enter image description here"></p> <p>Table Structure:</p> <pre><code> CREATE TABLE [dbo].[Account]( [AccountNumber] [int] NOT NULL, [AccountType] [nchar](10) NOT NULL, [Duration] [int] NOT NULL, [DepositedAmount] [int] 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] </code></pre> <p>CODE</p> <pre><code> public void UpdateAccount() { RepositoryLayer.Account acc1 = new RepositoryLayer.Account(); acc1.AccountNumber = 4; acc1.AccountType = "Verify"; accountRepository.UpdateChangesByAttachAndRefresh(acc1); accountRepository.SubmitChanges(); } public virtual void UpdateChangesByAttachAndRefresh(T entity) { //Can GetOriginalEntityState cause any bug? Is it unnecessary? if (GetTable().GetOriginalEntityState(entity) == null) { //If it is not already attached Context.GetTable&lt;T&gt;().Attach(entity); Context.Refresh(System.Data.Linq.RefreshMode.KeepCurrentValues, entity); } } </code></pre> <p>Generated SQL</p> <pre><code>UPDATE [dbo].[Account] SET [AccountType] = @p3, [Duration] = @p4 WHERE ([AccountNumber] = @p0) AND ([AccountType] = @p1) AND ([Duration] = @p2) AND ([DepositedAmount] IS NULL) -- @p0: Input Int (Size = -1; Prec = 0; Scale = 0) [4] -- @p1: Input NChar (Size = 10; Prec = 0; Scale = 0) [TEST ] -- @p2: Input Int (Size = -1; Prec = 0; Scale = 0) [10] -- @p3: Input NChar (Size = 10; Prec = 0; Scale = 0) [Verify] -- @p4: Input Int (Size = -1; Prec = 0; Scale = 0) [0] -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1 </code></pre> <p>READING:</p> <ol> <li><p><a href="https://stackoverflow.com/questions/2555206/can-linq-to-sql-omit-unspecified-columns-on-insert-so-a-database-default-value-i">Can LINQ-to-SQL omit unspecified columns on insert so a database default value is used?</a></p></li> <li><p><a href="https://stackoverflow.com/questions/2686036/how-can-i-bind-an-enum-to-a-dbtype-of-bit-or-int">How can I bind an Enum to a DbType of bit or int?</a></p></li> <li><p><a href="https://stackoverflow.com/questions/637121/linq-to-sql-why-am-i-getting-identity-insert-errors">Linq to SQL: Why am I getting IDENTITY_INSERT errors?</a></p></li> <li><p><a href="https://stackoverflow.com/questions/11189688/linq-to-sql-updating-without-refresh-when-updatecheck-never?lq=1">LINQ to SQL: Updating without Refresh when “UpdateCheck = Never”</a></p></li> </ol>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USCommunity
    1. USLijo
    plurals
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. PODefault Values (of C# variables) Issue in LINQ to SQL Update
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload