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<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2>Lisa,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2>From what you are saying, it sounds like your tree is
balanced, so why can't you relate at each level? Basically forget you've
got an inheritance going (it actually isn't relevant if you have a balanced
tree) and treat them as you would treat any other 2 sets of tables.
</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2>If you were trying to relate say surveytype with surveyobs
then you would have problems.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2>Or ah you asking how to automate the foreign key primary
key relationships?</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=406551719-06072009><FONT face=Arial
color=#0000ff size=2>Leo</FONT></SPAN></DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
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<FONT face=Tahoma size=2><B>From:</B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B>On Behalf Of </B>Lisa
Rockwell<BR><B>Sent:</B> Monday, July 06, 2009 2:47 PM<BR><B>To:</B>
postgis-users@postgis.refractions.net<BR><B>Subject:</B> [postgis-users]
Database design problem<BR></FONT><BR></DIV>
<DIV></DIV>I am having problems trying to model a relationship in my database
and I heard that the people on this forum enjoy a challenge.<BR><BR>I have 2
supertype tables, currently in a 1 to many relationship, that use table
inheritance and both have many subtypes. A record in the table 'Survey types'
describes records in the table 'Survey Observations' (a spatial
table).<BR><BR>So, 'Survey types' has children 'Survey type A', 'Survey type B',
etc., and 'Survey Observations' has children 'Survey Obs A', 'Survey Obs B',
etc. My problem is that I need 'Survey type A' to relate to 'Survey Obs A',
'Survey type B' to 'Survey Obs B', etc., where there will be a growing number of
subtype tables over the life of the database, as we expand and preform new types
of surveys. <BR><BR>I cannot think of a good way to connect these tables and it
is probably the most important relationship in the database.<BR><BR>I can send
you a jpg that better explains
this.<BR><BR>Thanks,<BR>Lisa<BR><BR></BODY></HTML>