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Re: View as front-end to function

From: Misa Simic <misa(dot)simic(at)gmail(dot)com>
To: Greg Spiegelberg <gspiegelberg(at)gmail(dot)com>
Cc: "[ADMIN]" <pgsql-admin(at)postgresql(dot)org>
Subject: Re: View as front-end to function
Date: 2012-06-20 16:01:40
Message-ID: CAH3i69kPT29fZFDvsAR70FQj=OJFkQAEohfgiZjfFZpTyEyetg@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-admin
Hi Greg,

I think it is Foreign Data Wrapper feature what already exist in Postgres

http://wiki.postgresql.org/wiki/Foreign_data_wrappers

So basically, you would need to write your own sourse fdw...

Kind Regards,

Misa

2012/6/20 Greg Spiegelberg <gspiegelberg(at)gmail(dot)com>

> Hi list,
>
> I've done some research on the subject and found only some dated threads
> on this topic.  Wondering if anything has changed.
>
> What I am looking for is a way to create a VIEW that is a front-end to a
> function.  Any conditions in the WHERE clause would be passed as parameters
> to the function.  For example, the query on VIEW queryme_v
>
>   SELECT * FROM queryme_v WHERE x=1 AND y='Y';
>
> would result in the function in the VIEW definition being executed as
> myfunc(1, 'Y').  From what I can tell, the only way to accomplish this
> today is to simply query the function instead of the VIEW:
>
>   SELECT myfunc(1, 'Y') x(c1, c2, c3, ...);
>
> I'm aware of the arguments for using SQL to perform the filter on the
> results from the VIEW however let me explain my use case.  The functions I
> need to create will act as an interface to an API that acts as a front-end
> to many large databases.  Simply returning everything over possibly slow
> connections isn't feasible or efficient.  The API exists to implement the
> business logic, filter the data, properly construct the query, decide which
> database is the target, execute and prevent a flood of information back to
> the client.
>
> For the sake of argument, let's just say I have the most recent stable
> PostgreSQL installed.  The API is Gdata-like for those of you who may be
> interested.
>
> Thoughts?  Possible with a RULE or a TRIGGER?
>
> -Greg
>
>

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