DBConcurrencyException With ON DELETE CASCADE

  • Thread starter Thread starter Andrea Caldarone
  • Start date Start date
A

Andrea Caldarone

Hi all,

in my SQL Server 2005 database I've two tables linked by the classic
relationship PrimaryKey->ForeignKey, I've added the clause "ON DELETE
CASCADE" to the ForeignKey constraint, so when I delete a record in the
parent table, SQL deletes for me the records in the child table.
This two tables are part of a dataset in my Visual Studio .Net project, they
populate two DataTables via two distinct sqlDataAdapter with the .FillSchema
and .Fill method of the adapters, in this way the ForeignKey contraint is
build in my dataset, infact if I delete a row in the parent DataTable,
Visual Studio deletes the rows in the child DataTable.
But when I try to call the .Update method of the two Adapters I receive an
exception: DBConcurrencyException I think that this exception is trown
because Visual Studio tries to delete some rows that SQL Server has just
deleted in response to the deletion of the the parent row operated by the
DeleteCommand of the .Update Method of the parent sqlDataAdapter.
 
You can subscribe to RowUpdated event of parent table SqlDataAdapter. In
the event handler you can navigate through parent-child relation to find all
children rows, then you can call AcceptChanges on these rows. In that way
the child table SqlDataAdapter will not execute the DeleteCommand and you
will not get DbConcurrencyException.

Pseudo code:

event handler ParentTableAdapter.RowUpdated
if action is delete then
for each child row in row.GetChildRows
row.AcceptChanges
next row
end if
end event handler

Regards:

Jesús López
 
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