When you said MI only performs joins on base tables, you hit the nail on the
head.  You have to take your OwnerMeterLink table and perform a Save Copy
As. I suggest that you alter the name of the Save Copy As table to
distinguish it from the named query created by the Into Table Named part of
the first SQL.  Close the query formed table and open the table you just
created, then run the second SQL.  Love MI, but its kindda clunky when you
get to relational stuff.  You may want to set up Access as a front end in
cases like this.  The problem here is that you lose the functionality of the
OwnerMeterLink table refreshing itself every time you open the work space,
so you'll have to do the Save Copy As every time, be sure to delete old
tables first, cuz renaming is required instead of overwriting when you do
this.

Another approach maybe to map the Excel spreadsheet using the same linking
fields, then do a Point thematic on the mapped symbols instead of a region
thematic.  I assume you will want to do this by ranges of consumption. I am
a little under informed here about table structure, but it seems to me that
there must be locational information in the table that holds the consumption
values, either by PID or address, or ???, so I would try to geocode that
table.  I just re-read you PS, kindda takes the wind of this sail.  But
really, geocoding every three months doesn't seem like a big deal, and
there's nothing like finding and correcting  a few unmatched records to keep
your data straight.

William "Woody" Woodruff
Zoning Administrator
Charter Township of Union, Isabella County, Michigan
(989) 772 4600 EXT 41
Visit our web site at http://www.geocities.com/ctuzoning/index.htm


-----Original Message-----
From: James Torrie [mailto:jamest@;rangdc.govt.nz]
Sent: Wednesday, November 06, 2002 7:25 PM
To: [EMAIL PROTECTED]
Subject: MI-L Linking Multiple Tables


Dear Listers
I am trying to thematically map water usage by land parcel using three
tables. The three tables are...

Parcel.tab is the land parcel polygons.

Owner.tab are points with contact details. A parcel may have multiple
owners, and multiple parcels may belong to one owner.IE Many to Many
relationship.

WaterMeter.tab is an unmapped Excel spreadsheet listing each Owner's KeyID
and quarterly water consumption data. An owner may have more than one meter
and a meter may supply more than one parcel.

If I run this SQL statement...

Select *
>From OwnerDetails,WaterMeter
Where Owner.KeyID = WaterMeter.KeyID
 into Table Named OwnerMeterLink

I get a table with all fields from the two tables. Great!

The problem is the next step.

Select Sum(WaterMeter.Q1Units),Owner.KeyID
>From Parcel, OwnerMeterLink
where Parcel.obj contains OwnerMeterLink.obj

MI only allows dynamic joins between base tables.
How can I set up my workspace to dynamically link the Watermeter table to
the parcel table?

The end result I am trying to achieve is to show the sum of the water used
by all meters associated with each parcel.

James Torrie
GIS Officer
Rangitikei District Council
New Zealand

PS I dont want to have to geocode the excel spreadsheet every 3 months (if a
meter supplies two parcels, only one parcel will recieve a point label), and
I musn't add extra fields to the tables.


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