I have been experimenting on using Dbman for a while. Presently we use its web interface for subjects to sign up for experiments. For example, we have three experiments at each time for subjects to sign up. After we have conducted each experiment, I have to edit the default.db file to remove the data of that experiment field for each record manually. Then I'll reuse this field and post another coming experiment. In this case, the number of field is always fixed.

Now we are thinking to keep track of all experiments that each record holder (students) has ever participated. That means I have to expand the number of field each time an experiment is announced. Then I have to add a delimiter to all the records in default.db. Unfortunately, we'll have 30-40 experiments each year.

Is it possible for Dbman to handle this ever expanding number of fields? Does Dbman support relational database?

Thx a lot for your help!

 
The number of fields is not a major factor in DBMAN. There have been some DBMAN projects that include up to 200 fields. The major factor is the SIZE of your database files. If you anticipate that your database file will grow to the upper limits of 1 MG, then you might want to consider upgrading to the SQL version of DBMAN, which eliminates a lot of the server processing overhead and also maintains fast and efficient searches.

In terms of "relational databases", DBMAN is not currently set-up to handle this. If you have multiple database files, you could do the following:

1) Create separate html.pl and default.cfg for each database file. (Refer to the Topics that discuss "Multiple Databases" in this Forum.)

2) Use radio buttons to designate databases in your search form. (Refer to the many Topics that discuss "Radio Buttons in Search Forms" in this Forum.)

3) Use keyword search fields to search accross different databases.

If your database files have the same structure with the same fields, then it can be done with a little tweaking. But if your database files are dramatically different, then it will be complicated.

Regards,

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Eliot Lee
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Anthro TECH, L.L.C
http://www.anthrotech.com/
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Coconino Community College
http://www.coco.cc.az.us/
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elee@coco.cc.az.us

You can, with a lot of work, simulate a relational database with DBMan. But, if I understand what your problem is correctly, this would be a tricky thing to do even in Access.

If each student was only in one experiment or if each experiment only had one student, it would be pretty easy to set up a "one-to-many" relationship between two databases. But with your setup -- many students participating in many experiments -- that's pretty hard to do.

You would need to have three databases -- one for students, one for experiments, and one for participation in experiments. The third database would have fields to hold the key value from the student database and the key value for the experiment database.

It is really complicated.


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JPD