Re: bytea

Hi Christoph,

Thanks for your reply. But what I want to do is loading a file of a particular path with a sql
statement in psql. Why I need to care about how the file looks like? Thanks.

Adrian

----- Original Message -----
From: "Christoph Haller" <ch@rodos.fzk.de>
To: <pgsql-sql@postgresql.org>
Cc: <achong@cecid.hku.hk>
Sent: Wednesday, February 05, 2003 6:15 PM
Subject: Re: [SQL] bytea


> >
> > I have a table containing a field of type bytea:
> >
> > CREATE TABLE a_table (
> >     a_field bytea
> > );
> >
> > How can I import a file in a SQL script? What function I can use?
> >
> The documentation says as in PostgreSQL 7.2.1 (I doubt this changed
> significantly since)
>
> Octets of certain values must be escaped (but all octet values may be
> escaped) when used as part of a string literal in an SQL
> statement. In general, to escape an octet, it is converted into the
> three-digit octal number equivalent of its decimal octet value, and
> preceded by two backslashes.
>
> In general it goes like this
> INSERT INTO a_table ( a_field ) VALUES ( '\\000\\001\\002\\003' ) ;
> to load the first four ASCII characters.
> You did not mention how your file looks like.
> There is also a C function available called PQescapeBytea
> which does all the required escaping to store memory areas in bytea
> columns.
> Refer to Command Execution Functions within libpq - C Library for
> details.
>
> Regards, Christoph
>
>
>
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