Merge is adding 2 records to the dataset

[Hemang Shah]

What im doing:

Adding new record to my form.

Creating a temp dataset "dsChanges" by using getchanges()

dataadapter.update(dsChanges)

Then I merge my original dataset dsOriginal.merge(dsChanges)

But now my dataset has 2 records instead of 1,

one with the auto id field = -1 and one with the autoid field as the one
retrived from the database.

The database has only 1 record added though.(which is correct).

Anyone got any inputs on this one ?

Thanks

 

[Miha Markic [MVP C#]]

Hi Hemang,

Yes, this is how Merge works - it looks at primary key to find out whether
row exists or not and it is not very Update friendly.
In autoinc case it thinks that there is a new row since the primary keys
differ.
This is how I solve it:
Before doing update I link same rows from original and getchanges dataset (I
create an array of instances of a class that holds references to both rows)
After update I manually refresh the primary key of original rows from the
updated rows (first setting DataColumn.ReadOnly = false, refresh the value
and reset ReadOnly).
And then, I do the merge.

 

[news.microsoft.com]

What if i'm doing only 1 record update at a time.

Also my insert command also has a select statement which uses the @@Identity
to get the auto # assigned to the new row.

Are you saying I update the "dsOriginal" from "dsGetchanges" and then merge?

Then why merge at all ?

Do you have a code snippet I can use ? or any article/book you can point me
to.

Thanks.

HS

Hi Hemang,

Yes, this is how Merge works - it looks at primary key to find out whether
row exists or not and it is not very Update friendly.
In autoinc case it thinks that there is a new row since the primary keys
differ.
This is how I solve it:
Before doing update I link same rows from original and getchanges dataset
(I create an array of instances of a class that holds references to both
rows)
After update I manually refresh the primary key of original rows from the
updated rows (first setting DataColumn.ReadOnly = false, refresh the value
and reset ReadOnly).
And then, I do the merge.

--
Miha Markic [MVP C#] - RightHand .NET consulting & development
www.rthand.com
SLODUG - Slovene Developer Users Group www.codezone-si.info

What im doing:

Adding new record to my form.

Creating a temp dataset "dsChanges" by using getchanges()

dataadapter.update(dsChanges)

Then I merge my original dataset dsOriginal.merge(dsChanges)

But now my dataset has 2 records instead of 1,

one with the auto id field = -1 and one with the autoid field as the one
retrived from the database.

The database has only 1 record added though.(which is correct).

Anyone got any inputs on this one ?

Thanks

 

[Miha Markic [MVP C#]]

What if i'm doing only 1 record update at a time.

Also my insert command also has a select statement which uses the
@@Identity to get the auto # assigned to the new row.

Are you saying I update the "dsOriginal" from "dsGetchanges" and then
merge?

No, I am saying only to update original primary key value so the Merge will
match the record.
Of course, nobody prohibits you to do all merging by yourself...

 

[Hemang Shah]

when you say "original primary key" value you mean update the "-1" that
dataset assigns to the one that the database generates which we get by
@@Identity ?

 

[Miha Markic [MVP C#]]

Exactly.