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.NET Forum / Languages / C# / May 2008delete multiple rows from table doesnt contain primary key
In my project,i added datagridview to my form , i transfered my table to datagridview and added multiple rows and when i called dataadapther.update ,,result is ok. But when i tried it for the delete operations,i got the error like "set primary key in your table" ,,i want delete multiple rows from Datatable which doesnt contain primary key If your table doesn't have a primary key, then you'll need to supply a WHERE clause that is distinct enough to disambiguate which rows to delete. Peter > In my project,i added datagridview to my form , i transfered my table to > datagridview and added multiple rows and when i called [quoted text clipped - 3 lines] > from > Datatable which doesnt contain primary key instead of supply where clause, i prefer choose row from table and delete it with "row.Delete(); dataAdapther.Update(table);" . idont understand why i am not allowed; what is the harm about it? why primary key is needed for delete but not for insert or update operations? thanks > If your table doesn't have a primary key, then you'll need to supply a WHERE > clause that is distinct enough to disambiguate which rows to delete. [quoted text clipped - 7 lines] > > from > > Datatable which doesnt contain primary key > instead of supply where clause, i prefer choose row from table and delete it > with [quoted text clipped - 14 lines] >>> from >>> Datatable which doesnt contain primary key What if you have multiple rows with the same data? I know you can simply say "I know I don't", but .NET can't *know* that, and it requires something to uniquely identify the rows to delete. On a different note, every table should have a primary key or you'll most likely have problems with it later on, like duplicate data.  SignatureLasse Vågsæther Karlsen mailto:lasse@vkarlsen.no http://presentationmode.blogspot.com/ PGP KeyID: 0xBCDEA2E3 Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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