Query changes before commit

[Dennis]

Hello,

I am inserting several records into a table within a transaction. There is one field in the table that should never have a duplicate value. If an attempt to insert a record that contains a value in that particular field that already exists in another record, then I want to detect this and copy the original record to a history table, then update the original record with the latest data. The table is being loaded from an xml file that can look something like this:

<parent>
    <child Code = "12345" Desc = "Some description" />
    <child Code = "12346" Desc = "Some description" />
    <child Code = "12347" Desc = "Some description" />
    <child Code = "12345" Desc = "Some different description" />
</parent>

Given the above XML snippet, I want to end up with:

Item Table:
ItemID                CODE              DESC
1                        "12345"            "Some different description"
2                        "12346"            "Some description"
3                        "12347"            "Some description"

and:

ItemHistory table:
ItemHistoryID     ItemID                CODE              DESC
1                        1                       "12345"            "Some description"

I do NOT want to end up with:

Item Table:
ItemID                CODE              DESC
1                        "12345"            "Some different description"
2                        "12346"            "Some description"
3                        "12347"            "Some description"
4                        "12345"            "Some description"

So, when I add each record to the Item context, I want to be able to detect if the CODE value already exists and take the appropriate action. However, since the transaction has not been committed, any record having such a duplicate is not available to be queried yet - at least as far I know.

Is there a method to query a context to see what records have been added but not committed yet?

Thanks,

Dennis

[IT-Als]

Hi Dennis,

Have you tried the GetChanges() method on the Context?

It will give you all the changes (inserts, updates and deletes) being performed on the next Commit/SaveChanges operation.

Here's a sample from the docs

Regards

Henrik

[Dennis]

Henrik,

That's exactly what I was looking for.

Thanks for directing me to it.

Dennis