Hi Rashad,
I give you answer about ORM only. I don't program in C++, but in web
application langage (PHP). I know that there is an ORM in Java who
enable spatial field. It's Hibernate Spatial
(http://www.hibernatespatial.org). I never user it but I supposed it
take in charge mostly spatial database (Oracle Spatial, PostGIS). But
you don't program in Java... nor me.
I was looking for a spatial ORM in PHP and I heard about Doctrine who
has "user-defined" type field. Many programmer seem to use this
solution. I think you should looking in that way for an ORM in C++. It's
a short term solution.
The other way is to write you own ORM or start to improve one who
already exists in C++... I think it's a long term solution who should be
developped in other langages than Java.
It's my conclusion after a couple of years of spatial programmation in PHP.
Best regard
Sylvain Racine
iGreffe Geomatique
Granby, Quebec, Canada
Le 2013-01-05 00:59, Rashad M a écrit :
Is it a good design idea to maintain separate tables for each layer in
a PostGIS database?. Every layer is defined by users. A user creates
his/her layer say ATM location. I dont have control over the table
definition of the layers much This makes it impossible to predict
fields(attribute fields and type are not known initially) used in the
table/layers. School vs roads have different geometry and set of
attributes.
The problem is traditional databases wont advice for having dynamic
tables very much. Does the same apply to spatial databases?
How to use ORM Database library with postgis table. I am using C++ and
libpq. but would like to change to an ORM model.
If i am using single table for every layer postgis may not work
because of geometry type. or i can have 3 table point, line, polygon
and data goes into the correct table based on geometry type.
Each table contains
layerId,featureId,geomety, data(hstore)
data = field1=>value1, field2=>value2 etcc
i need to use hstore for fields "data" because name/type of attributes
are not known before runntime.
Also layerId will be redundant in the table.
Fo example: a layer with 1Lakh features will have a column layerId 1L
times which will not be there if I use separate tables
for separate layers.
But does adding a new table for every layer may become a bottleneck?
BTW, I am writing a web app
--
Regards,
Rashad
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