Hello, I would like to bid on this job. I'm an American living in Tokyo, with many years experience in Perl programming and linux/windows, see my CV. Personally I think the high end of your budget is not a lot of money for what you require, but since I have written database editing tools a number of times I know what is required.
As I understand it, you have 2000 tables and the maximum number of rows per table will fit comfortably in one web page. If not I could add paging (say 100 rows per page) to save memory. The program would be done in Perl, and I would probably like to use Class::DBI though possibly just directly connect through the Mysql module if the table schema is not predefined.
It of course requires a lot more work to write a general tool that will handle any relations and table schemas you throw at it, so I don't think it is unreasonable to ask if you can please set one unchanging table schema in advance. Especially if you think you might want to scrap the current schema and add lots of relations. If you must have a general purpose editor then I will try to meet your requirements.
Another issue is that it is hard to use DHTML to enter a NULL. If I know where in the schema it allows NULLs I could add that to the program though.
If you want editting to be done in list view but do not want a Save button (but do want confirmations from the db), then every click will require a db transaction of course. If the database is near you or on the same machine then that is simple. If you want to handle a remote db with some latency in the connection, then you might want to say make the field red while it is being transacted and then clear the color away after the field has been updated from the database. But I would rather leave such options out given the budget.
Multiple selects, please explain what you want. Do you mean that you want to be able to type in your own SQL statement using multiple selects and edit the result?
When you have escrowed the money, I will start. I do not accept PayPal, but perhaps this site does (I believe they can in fact pay out to PayPal). This is a fair system, and does not require trust of an organization (PayPal) that has so many people who hate it for arbitrary acts, plus with escrow it can be cancelled easily. I will provide a demo running on my own linux mysql server with your sample data so you can confirm it, and all source code will be provided. You will be responsible for installation on your server.
Finally, I am curious about whether you have tried editing with the mysql windows client. It is not great but it would be helpful to know what parts you liked/disliked.
I hope you can give me this job since I'm experienced writing db editors, know mysql, and am interested in dhtml. First thing after escrow will be to do a mockup of the screen you want to see, including how to select data sets, etc. I don't know, maybe it is important for you to edit two datasets at once or something. Also I can do visualization of the data in a graph or something, of course for extra fee. I think other bidders ought to put as much thought into their bids as I do, maybe this is a good reason to go with me even though I don't have a long history with this site. Thanks.