Re: Traversing and modifying a table


2003-07-01 12:19:15 AM
delphi274
"Paul Linehan" <XXXX@XXXXX.COM>writes
Quote


XXXX@XXXXX.COM says...


>>Can you explain further what you mean here? Give us an example of data
>>before and after.


>Four fields are read, concatenated, and the MD5 hash of that value is
written
>as a 32 character hexadecimal string to a new field, which becomes the
record
>key (the four fields together guarantee uniqueness). Obviously, this is
not
>something that can be done in an SQL statement. It requires reading and
>modifying every record in the database. Using something like Paradox,
this
>is extremely fast. Using ADO and Access, it is fairly slow, but
functional
>without taking up a lot of memory. I have created a Firebird database of
all
>data (3 million records, which require separate tables/databases in
>Paradox/Access), for convenience in some of the tasks I have to do, such
as
>finding a match in any of the 3 million records.


Hmmm... I think that you're probably not getting a response because of
the use of Firebird. Have you tried doing what you want to do using
Interbase (even one of the OS editions?)?


Try that and repost to the interbase.general group, cos I don't think
there is enough traffic on this group - I am pretty sure that you will get
a better response there, plus it doesn't seem to be an IBExpress issue.
Otherwise try the FB groups which should also help.


BTW, I am pretty sure that you cannot guarantee uniqueness of your key
using MD5 hashes - it might be very rare, but it is conceivable that you
come across a collision.



Paul...


>- Mike

--

plinehan__AT__yahoo__DOT__com

C++ Builder 5 SP1, Interbase 6.0.1.6 IBX 5.04