Along the lines of, "what is an appropriate use of an object field", I've been considering this:
We are a manufacturing company with lots of tools and lots of products. Each tool has various attributes, but each tool type has a different set of characteristics. Silly example that I hope everyone can follow: if the tool type is "screwdriver" then the attributes might be: Tip Type (blade, Phillips, Torx, etc.) Tip Size (#1 or #2) Shank length (in mm) Handle diameter (in mm) ...If the tool type, however, is "hammer" then the attributes might be: Head type (claw, peen, sledge, etc.) Claw shape Head weight Shank material Shank length Grip Type ...and many more Common to all tools, regardless of tool type are attributes such as: Tool ID Tool Type - which determines the format and contents of the object field that contains the attributes Storage Location Purchase Date Condition (good, fair, poor, unusable) Status (ready to use, in use, lost) 90% of the time users want to enter a Tool ID to retrieve the Storage Location, Condition, and Status. 10% of the time they know the tool type but don't know the tool ID and want to query for a tool to do the job, using one or several attributes. I've been thinking that because there are so many tool types and so many attribute "collections", an object field might be a good place to store the attribute data in name-value pairs. This way I don't have to have a table with every single attribute name, which would be a problem because I don't know them in advance (users want to be able to specify the attributes themselves, along with the attribute value of course) and many tools do not share many attributes, so a big mostly-empty record would result if I used fields. The object field on a record with Tool Type = "screwdriver" would contain attributes for a screwdriver, while the object field on a record with a different Tool Type would contain a different set of attributes. A table for "Tool Type" would have one record for each tool type and could also use an object field to contain the attribute names, since this would be more handy than having multiple records for each tool type, one for each attribute name. The normalized, relational model isn't really needed here, though of course it could be used. An object field seems ideal for this kind of application, and 'Query by Attribute' certainly makes it possible. There are always LOTS of ways to solve a problem, but do you agree that an object field is a good way to solve this one? If it is a mediocre way to solve it, I'd like to hear your comments! Bob Miller Chomerics, a division of Parker Hannifin Corporation ********************************************************************** 4D Internet Users Group (4D iNUG) FAQ: http://lists.4d.com/faqnug.html Archive: http://lists.4d.com/archives.html Options: http://lists.4d.com/mailman/options/4d_tech Unsub: mailto:[email protected] **********************************************************************
