Re: DatabaseMetaData.getTypeInfo() - returns all tables as well

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От Thomas Kellerer
Тема Re: DatabaseMetaData.getTypeInfo() - returns all tables as well
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Msg-id n04lmu$pk6$1@ger.gmane.org
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Ответ на Re: DatabaseMetaData.getTypeInfo() - returns all tables as well  (Dave Cramer <pg@fastcrypt.com>)
Ответы Re: DatabaseMetaData.getTypeInfo() - returns all tables as well
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No particular problem besides performance.

But I'm surprised: why would this break anything?
Why does the driver rely on tables from pg_catalog be returned for type information?

Thomas

Dave Cramer schrieb am 19.10.2015 um 17:33:
> This change breaks more than it fixes!
>
> What is your specific problem with returning tables ?
>
> Dave Cramer
>
> davec@postgresintl.com <mailto:davec@postgresintl.com>
> www.postgresintl.com <http://www.postgresintl.com>
>
> On 1 October 2015 at 08:51, Thomas Kellerer <spam_eater@gmx.net <mailto:spam_eater@gmx.net>> wrote:
>
>     Sorry, I am not registered with GitHub (nor using it)
>
>     Regards
>     Thomas
>
>     Dave Cramer schrieb am 01.10.2015 um 13:23:
>     > Hi Thomas,
>     >
>     > Any chance you could provide a github pull request ?
>     >
>     > Dave Cramer
>     >
>     > dave.cramer(at)credativ(dot)ca
>     > http://www.credativ.ca
>     >
>     > On 30 September 2015 at 15:37, Thomas Kellerer <spam_eater@gmx.net <mailto:spam_eater@gmx.net>
<mailto:spam_eater@gmx.net<mailto:spam_eater@gmx.net>>> wrote: 
>     >
>     >     Hello,
>     >
>     >     DatabaseMetaData.getTypeInfo() returns not only data types, but also all table types.
>     >
>     >     Strictly speaking this is correct as the row type for a table is indeed a "data type" in Postgres,
>     >     but I think the information returned is way too much from a practical point of view.
>     >
>     >     This could be reduced at least a bit by not only excluding pg_toast, but also pg_catalog and
information_schematypes: 
>     >
>     >       SELECT t.typname,t.oid
>     >       FROM pg_catalog.pg_type t
>     >         JOIN pg_catalog.pg_namespace n ON (t.typnamespace = n.oid)
>     >       WHERE n.nspname not in ('pg_toast', 'pg_catalog', 'information_schema')
>     >
>     >     (instead of WHERE n.nspname != 'pg_toast' in AbstractJdbc2DatabaseMetaData.java getTypeInfo())
>     >
>     >
>     >     What I find even more confusing (from a JDBC point of view) is that each table type is reported twice:
>     >
>     >     Once with the table's name and once with an underscore prefixing the table name, e.g. foo and _foo.
>     >
>     >     These entries map to pg_type rows with typtype = 'c' and 'b' respectively.
>     >
>     >     I wonder if it would make sense to filter out the "real" tables from this result.
>     >     And if it does, if there is an efficient way of doing that and not removing real composite types
>     >     from the result at the same time.
>     >
>     >
>     >     Regards
>     >     Thomas
>     >
>     >
>     >
>     >
>     >     --
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