How to update using DataSet (C# and MySQL) with the database with no primary key

Question

I am working on windows application using c# and MySQL. I inserted new record by reading text file into MySQL database, Database having no primary key but combination of four columns we can consider as component of primary key (but actually database having no primary key). I know how to add and update record using DataAdapter and DataSet. But I can not update a record in the database having no primary key.

Can you please guide me, how can I update a record in the database with a database having no primary key.

Thanks.

Answer 1

Assuming you have next table:

column1,
column2,
..
columnN,
target -- column to update

then use:

UPDATE table
SET
   target = @target
WHERE
   column1 = @va1, column2 = @val, -- etc specify all columns in table

If you have duplicated (absolute equal) records, you will update all of them.

Answer 2

For this to work with a Dataset you need to define your update command "By-Hand".

You need to set the proper DataAdapter.UpdateCommand.

In my point of view it would be a better approach to just add a primary key column to the table.