A discography is a compilation of information, like a bibliography or a catalogue. Popular belief seems to be that you cannot copyright a collection of information. This is false. While the information may remain free the organisation and presentation of that information does not (as long as it demonstrates some thought and work on the part of the discographer). Read any recent textbook on intellectual property for more details.
When I claim copyright on a discography it means I've put a considerable amount of work into tracking down original copies of the records involved, contacting bandmembers and collectors for precise information, collating the information, typing it in, thinking hard about the best way to organise and present the material clearly and concisely. I only claim copyright if I believe I've done hard work and have presented the information in an original manner.
Therefore I don't look kindly on people who download my work, edit it slightly and then publish it in their magazines without even credit. This has happened three times. Don't do it.
Again, if you want to use one of my discographies in your publication ask first. If you are merely using my discography as a source of information please credit me and any coauthors.
If you don't want to credit anyone at all then go and do the work yourself. If you're going to ignore all I've said above you'd better check carefully to find the deliberate mistakes planted in the discographies.
PS The links above are to US copyright law, all signatories to the Berne convention recognise similar or identical principles.