Обсуждение: pgsql functions: get column headers; optional arguments

Hi. I hope this is the correct mailing list.

I am writing a function to extract data either from a table or a query
and output it in xml. I have the logic down, but I cannot work out a few
things.

1. How can I read the column headings from the returned data set? I have
resorted to writing the same function in tcl in which I can work out how
to do this, but what about pgsql? I can't use the system tables for
this, since the data may not come from a table.

2. It it possible, either in tcl or pgsql, to have optional function
arguments?

Thanks,

Mark
--


  Mark Simon

Manngo Net Pty Ltd

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Mark wrote:
> I am writing a function to extract data either from a table or a query

> and output it in xml. I have the logic down, but I cannot work out a
few
> things.
>
> 1. How can I read the column headings from the returned data set? I
have
> resorted to writing the same function in tcl in which I can work out
how
> to do this, but what about pgsql? I can't use the system tables for
> this, since the data may not come from a table.

I don't think there is a way.

> 2. It it possible, either in tcl or pgsql, to have optional function
> arguments?

No.

Before you do a lot of work on this, check out the xml2 contrib module.
It may provide a lot of what you need.

There will also be XML stuff in 8.3 core.

Yours,
Laurenz Albe