Sorry, but most of the "Dallas" database is not available in English. It contains information on most of the characters appearing in the TV series (1.203 entries). It does not claim to be official or complete.
You may want to take a look at one of the central database entries, the one about J. R. Ewing, or maybe you are interested in
the German introduction to the database,
a search form that enables you to perform a keyword search!
Following any of the above-mentioned links will take you to the German version of my webpages; however:
There is an English version of the "Dallas" family tree available!