|
|
Object Database Tech Notes
Okay if you're still here, you must be really interested in the details of the Object Database.
Facts
Some random facts to thrill the fact-knower in you!
- The database can be up to 25 levels deep.
- From Doug Baron: "255 is the limit for the string representation of an address. But if you have 20 levels of hierarachy, with 30 character names at each level, you should still be able to refer to any item based on it's parent table. Coercing that item's address to a string will yield a garbage value, however."
- A table can hold an unlimited number of items (limits are memory and disk
space).
- It thus follows that the root can be any size, limits again being memory and disk space). The largest root I've heard of is 100 megabytes.
- A table can hold unlimited numbers of items, however, display performance issues makes them difficult to edit manually at about 500 objects or so. Of course, with the window closed, a script can easily operate on that large table relatively quickly.
- When Frontier checks the system.paths table to find an addresses, it works through the table from top to bottom. So the first entry in the table has the highest priority. Again, you shouldn't edit system.paths. Bad things will happen.
- The most efficient tables are built deep, not wide.
- Pref to turn off saving off/on database on close: user.prefs.autosave
- One time escape from saving: hold down shift while you quit
Links
Scripting.com has a page on the ODB in the Frontier 5 User's Guide:
http://www.scripting.com/frontier5/manual/chapter06.html
Feedback
If you have any other tips about using the database, or if you see inaccuracies in this tutorial, please let us know.
tutorials@scriptmeridian.org
Thanks!
Page 1: Frontier's Database Defined
Page 2: The Advantages of Frontier's Database
Page 3: What's in the root?
Page 4: Navigating the Root
Page 5: Where do I keep my stuff?
Page 6: Database Names and Addresses
Page 7: Database Care and Feeding
Page 8: Object Database Tech Notes
[ Previous - Next ]
This tutorial was written by Philip Suh in Osaka, Japan.
Page last revised 3/3/98; 6:31:15 AM.
Copyright © 1998 ScriptMeridian. All rights reserved
All trademarks are the property of their respective owners.
4:10:08 AM Wednesday, April 15, 1998
|
News