Relational database suppliers are unimpressed by claims from database consultancy Butler Bloor about an alleged bug in the way they have implemented standard database query language SQL. Earlier this year Butler Bloor unearthed a flaw in they way some suppliers – which the consultancy has refused to name – implemented cursors, subsets of data.

According to Butler Bloor, this could lead users to lose updates bacause some SQL implementations use copies of data rather then pointers.

Now the Milton Keynes company has revealed details of a related bug, using a fragment of SQL code to show how updates can be lost.

Butler Bloor ran this code on seven different database products