Going crazy comparing bytea columns
Hi,
I am new to Postgresql, so pls be patient.
I am using npgsql with C# to insert a bytea value into a
column which will serve as an encrypted password. This works
well. However, when I retrieve the value, it is different.
In other words, "select pwd from table where pwd like @pwd"
does not work.
Is it not possible to compare bytea columns?
...get dbConn...
NpgsqlCommand cmd = new NpgsqlCommand("select pwd from table
where usr = @usr and pwd like @pwd",dbConn);
cmd.Parameters.Add(new NpgsqlParameter("usr",DbType.String);
cmd.Parameters.Add(new
NpgsqlParameter("pwd",NpgsqlTypes.NpgsqlDbType.Bytea);
cmd.prepare()
... set param values, call executereader...
Thanks,
JM
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scomp@canada.com writes:
I am using npgsql with C# to insert a bytea value into a
column which will serve as an encrypted password. This works
well. However, when I retrieve the value, it is different.
In other words, "select pwd from table where pwd like @pwd"
does not work.
Why are you using LIKE when you apparently want simple equality?
ISTM that LIKE opens up a whole can of worms with possible appearance
of the wildcards (% and _, not to mention \) in the string.
Another likely source of trouble is that you're not dealing with
escaping of non-ASCII byte values the same way when you insert
the password as when you try to look it up.
regards, tom lane
On Wed, Mar 01, 2006 at 10:40:39AM -0800, scomp@canada.com wrote:
I am using npgsql with C# to insert a bytea value into a
column which will serve as an encrypted password. This works
well. However, when I retrieve the value, it is different.
Different how? Without knowing more I'd wonder it's a matter of
escaped vs. non-escaped bytea values.
In other words, "select pwd from table where pwd like @pwd"
does not work.Is it not possible to compare bytea columns?
I can't help with npgsql but it's certainly possible to compare
bytea columns. Incidentally, I don't know if this could be causing
any problems, but why are you using LIKE instead of "="?
NpgsqlCommand cmd = new NpgsqlCommand("select pwd from table
where usr = @usr and pwd like @pwd",dbConn);
What's the output of the following query?
SELECT pwd, @pwd FROM table WHERE usr = @usr
That should return the value in the database (pwd) and the value
you're providing (@pwd). Let's see how they differ.
--
Michael Fuhr