Sql – Linq to SQL – How to find the value of the IDENTITY column after InsertOnSubmit()

identity-columnlinqlinq-to-sqlsql

I am using LINQ to SQL to insert simple data into a table WITHOUT a stored procedure. The table has a Primary Key ID column, which is set as an IDENTITY column in both SQL Server and in my DBML.

First I call InsertOnSubmit(); with data for a single row, and then I call SubmitChanges(); to commit the row to the db. But I think there must be a simple way to then retrieve the row's IDENTITY column value of the newly inserted row. I don't wish to provide the IDENTITY column value to the db, I want it to generate one for me.

How is this best handled?

Best Answer

here is a simple code snippet

            Dim odb As New DataClassesDataContext
            Dim tst As New test
            tst.name = "abcd"
            odb.tests.InsertOnSubmit(tst)
            odb.SubmitChanges()
            Response.Write("id:" + tst.id.ToString)

so, basically the object you used in InsertOnSubmit will get the identity field populated after the record has been created in the database

Syntax:

ALTER TABLE {TABLENAME} 
ADD {COLUMNNAME} {TYPE} {NULL|NOT NULL} 
CONSTRAINT {CONSTRAINT_NAME} DEFAULT {DEFAULT_VALUE}
WITH VALUES

Example:

ALTER TABLE SomeTable
        ADD SomeCol Bit NULL --Or NOT NULL.
 CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated.
    DEFAULT (0)--Optional Default-Constraint.
WITH VALUES --Add if Column is Nullable and you want the Default Value for Existing Records.

Notes:

Optional Constraint Name:
If you leave out CONSTRAINT D_SomeTable_SomeCol then SQL Server will autogenerate
a Default-Contraint with a funny Name like: DF__SomeTa__SomeC__4FB7FEF6

Optional With-Values Statement:
The WITH VALUES is only needed when your Column is Nullable
and you want the Default Value used for Existing Records.
If your Column is NOT NULL, then it will automatically use the Default Value
for all Existing Records, whether you specify WITH VALUES or not.

How Inserts work with a Default-Constraint:
If you insert a Record into SomeTable and do not Specify SomeCol's value, then it will Default to 0.
If you insert a Record and Specify SomeCol's value as NULL (and your column allows nulls),
then the Default-Constraint will not be used and NULL will be inserted as the Value.

Notes were based on everyone's great feedback below.
Special Thanks to:
@Yatrix, @WalterStabosz, @YahooSerious, and @StackMan for their Comments.

Sql – How to return only the Date from a SQL Server DateTime datatype

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, @your_date))

for example

SELECT DATEADD(dd, 0, DATEDIFF(dd, 0, GETDATE()))

gives me

2008-09-22 00:00:00.000

Pros:

No varchar<->datetime conversions required
No need to think about locale

Best Answer

Related Solutions

Sql – Add a column with a default value to an existing table in SQL Server

Syntax:

Example:

Notes:

Sql – How to return only the Date from a SQL Server DateTime datatype

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