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From: kenn@intrbas.uucp (Kenneth G. Goutal)
Newsgroups: comp.databases
Subject: Re: database containing gray-scale graphic images
Summary: InterBase can do it on SCO platforms
Keywords: gray-scale graphic images blobs
Message-ID: <117@intrbas.UUCP>
Date: 20 Dec 90 00:13:32 GMT
References: <1990Dec19.181537.10103@usenet.ins.cwru.edu>
Sender: news@intrbasintrbas.UUCP
Organization: Interbase Software Corporation
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InterBase is a relational dbms that runs on SCO Unix and SCO Xenix
and can handle graphics perfectly well, in fields of a type called a 'blob'.
From a programming standpoint, a blob looks a lot like a Unix file --
an unstructured stream of an arbitrary number of raw bytes.
Once a record has been selected, the field can be read with getb()
calls much as one might read a Unix file with getc() calls.
One can also read large chunks of a blob called 'segments',
just for efficiency's sake.  Finally, there is a function called 
blob_dump() that dumps the field into a real Unix file,
for those cases where that turns out to be useful.
A parallel set of functions are available for writing the field
when storing a new record into the relation or modifying an existing one.

We also have a notion called 'blob filters', which are functions you
can define and make part of the access method code and are invoked
whenever it's appropriate to convert from one kind of a blob to another,
e.g. in this case perhaps converting some internal representation of
gray scale to different formats for different kinds of display hardware
and/or software.

Sorry, no Mac implementation at this time.

-- Kenn Goutal
   Technical Support

Interbase Software Corporation
209 Burlington Road
Bedford  MA  01730
617.275.3222
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