[R] RMySQL and Blob

David James dj at research.bell-labs.com
Wed Sep 22 16:04:54 CEST 2004

Hi Jonathan,

Currently RMySQL doesn't handle blob objects.  The mechanics of
inserting and extracting blob objects by itself is not too hard,
but issues such as how should blobs be made available to R, how to
prevent buffers overflows, how to prevent huge blobs from exhausting
the available memory, should R callback functions be invoked
as chunks of the blob are brought in, etc., need more consideration.
And these issues are not R/MySQL specific, but also relevant to
other databases and other non-dbms interfaces.

BTW there are R facilities (e.g., external pointers, finalizers) that 
seems quite important for this type of implementation.  

What type and how big are the blobs that want to import?


jonathan_li at agilent.com wrote:
> Dear R experts,
> Does RMySQL package handle Blob datatype in a MySQL database? Blob can represent an image, a sound or some other 
> large and complex binary objects. In an article published by R-database special interest group, named "A common database interface (DBI)" (updated June 2003),  it's mentioned in "open issues and limitations" that "We need to carefully plan how to deal with binary objects". 
> Before I invest time to try, I would appreciate any experts' opinions.
> Thanks,
> Jonathan
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