Neil Conway <nconway(at)klamath(dot)dyndns(dot)org> writes:
> I want to store some binary data in Postgres. The data is an
> MD5 checksum of the user's password, in binary. It will be
> exactly 16 bytes (since it is a one-way hash).
> Can I store this safely in a CHAR column?
No. CHAR and friends assume there are no null (zero) bytes.
In MULTIBYTE setups there are probably additional constraints.
You could use bytea, but I would recommend converting the checksum
to a hex digit string and then storing that in a char-type field.
Hex is the usual textual representation for MD5 values, no?
regards, tom lane