Re: Escape handling in COPY, strings, psql

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Peter Eisentraut <peter_e(at)gmx(dot)net>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Sergey Ten <sergey(at)sourcelabs(dot)com>, "'Christopher Kings-Lynne'" <chriskl(at)familyhealth(dot)com(dot)au>, jason(at)sourcelabs(dot)com
Subject: Re: Escape handling in COPY, strings, psql
Date: 2005-05-30 14:28:17
Message-ID: 200505301428.j4UESH210277@candle.pha.pa.us
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Peter Eisentraut wrote:
> Bruce Momjian wrote:
> > I was suggesting ESCAPE 'string' or ESC 'string'. The marker has to
> > be before the string so scan.l can alter its processing of the string
> > --- after the string is too late --- there is no way to undo any
> > escaping that has happened, and it might already be used by gram.y.
>
> That pretty much corresponds to my E'string' proposal. Both are
> probably equally trivial to implement.

Right. I think your E'' idea has the benefit of fitting with our
existing X'' and B'' modifiers. It is also simpler and cleaner to do in
scan.l, so I think your idea is best.

> > I agree with Tom that COPY has to be left unchanged. The fundamental
> > problem is the representation of NULL values, that I don't think we
> > can do without some escape mechanism. Single-quote escapes works by
> > doubling them, but once you need to represent something more like
> > null's, I can't think of a solution without escapes.
>
> Yes, I now realize that COPY has a whole set of different rules anyway,
> so we can leave that out of this discussion.

Cool.

--
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