[DUG] Runtime user defined fields

[Steve Peacocke]

Hi everyone,

I've been away from programming for a while so please excuse the
seemingly simple question.

I'm designing a user interface for a new application and wondered if
there was a generally accepted way that this "should" be done.

The application will allow end users to edit their forms allowing them
to add, move, and remove fields at runtime. I'm using MySQL but I was
wondering if there was an accepted way of adding and changing fields
to a database.

I know I can use SQL for this but I also don't want to make every
application unable to be managed or upgraded. Perhaps I can ensure
that the 3-4 permanent fields are never able to be altered (ID, Name,
etc) but allow the user (through a suitable user-friendly interface)
to go crazy adding such fields as My_favourite_colour, Rating,
Priority, Notes, etc. etc.

I'm able to give a suitable user-friendly interface to allow them to
physically alter the Delphi form at runtime, but wondered about the
"most appropriate way" to modify the fields to the database.

1. I could simply add fields using SQL's ALTER TABLE
2. I could add another table with fields such as TableName, FieldName,
Type, etc.. and add to that
3. Some other spiffy way that you people will suggest that I haven't
even thought of yet.

Any suggestions?


Steve Peacocke
+64 220 612-611
http://www.nzorient.co.nz