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 Introducing PTWin32 |
Some
of our users are puzzled by the lack of a direct relationship between a Parcel
record and its Owner record(s). Usually these people have used older software
systems that require the entry and storage of redundant information for each
record created. This contributes to making systems big and slow so we have not
adopted these methods for PTWin32. Instead,
we keep a single copy of information pertaining to a specific owner in a master
list of Owners. This one record is then attached to any number of
applicable Parcel records. This way you don’t enter the same
information like owner name and address over and over again and you don’t get
conflicting copies of the same information that invalidate each other. Consider
this: Usually relationships between records in different tables are defined by
having a single master record that has many detail records attached. For
example, a single Contractor record can have any number of Employee
records attached. Now
let’s consider Parcel records. A single Parcel record can have
any number of Owner records attached since more than one person can own a
parcel. The Parcel is the master and the Owners are the detail
records. To
solve the problem caused by these dueling one-to-many record relationships we
established a third table that acts as a junction between Parcels and Owners. This third table is called Lkparown,
which is an abbreviation for “Link Parcels & Owners”. And it
resolves the multiple one-to-many conflicts. Each Parcel and Owner record
entered into PTWin32 is assigned a unique number by the system. This “Key”
value identifies the record to other related records. This way complex
relationships can be stored in minimum space by linking only the “Key”
values. This is what Lkparown does. The table stores one record of Parcel
Key and Owner Key values for every Parcel/Owner relationship.
In other words, if two people own a Parcel its Parcel Key will
appear in two Lkparown records, one for each Owner. On the flip
side, an Owner will have a Lkparown record for each Parcel
owned thus allowing us to maintain many one-to-many relationships. There
is a second place in PTWin32 where many one-to-manys conflict. This is between Permits
and Contractors. A Permit may have many Contractors and a Contractor
may be assigned to many Permits. In this case a third table called Lkprmcon
is used. So
the next time you’re creating a report and wonder why there is a table between
Parcels and Owners, remember the many one-to-manys and keep in
mind the data entry work that is being saved.
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