Howard Wilkinson (h...@cohtech.com)

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Richard Huxton wrote:
> Howard Wilkinson wrote:
>> I am working on some upgrades to the MyDNS open source product. I
>> have some expertise in MySQL but am not overly familiar with
>> PostgreSQL and need some guidance on how to query the schema for the
>> maximum size of data a column can hold.
>
> Unless you're after PG-specific stuff, it's probably best to use the
> information-schema.
>
> http://www.postgresql.org/docs/8.3/static/information-schema.html
>
> This has a standard layout cross-database, so will help you to extend
> you app across other systems. I think it's supported in the latest
> version of MySQL too.
>
SO I can do something like this?

select character_maximum_length from information_schema.columns where
table_name='rr' and column_name='data';

Yes?

I am working on some upgrades to the MyDNS open source product. I have
some expertise in MySQL but am not overly familiar with PostgreSQL and
need some guidance on how to query the schema for the maximum size of
data a column can hold.

In MySQL I can do either: a "DESCRIBE" command or do "SELECT COLUMNS"
command. And then parse the result for the length in the type column of
the row returned. How would I do a similar function using PostgreSQL - I
have tried to find this in the manuals and in this mailing list but not
found any pointers to get me started.

Apologies for asking such a simple question but I am being a bit lazy as
I want to get on with releasing the MyDNS code.

Regards, Howard.