[Building Sakai] Reading Contents of Content_Resource Binary_Entity Column

[Matthew Jones]

This field is actually a specially encoded binary, and you'll need to read
this with code. The code that parses this out, I believe, is the
EntityReader (readSqlResultRecord) You might get some ideas from the
functions that allowed this column to be copied to a file as part of a
database->filesystem conversion.

The full details of the format are on described on the entity encoding page
on confluence [1] if you wanted to try to reproduce it in some other
language.

convertToFile() and putResourceBodyFilesystem() are the specific functions
that do db->file.

They are in this file in the kernel:
https://source.sakaiproject.org/svn/kernel/trunk/kernel-impl/src/main/java/org/sakaiproject/content/impl/DbContentService.java

This query in oracle *kind of* will show you the data in this in text
format. Many things have identifiers or block lengths so are unprintable. I
don't know the mysql equivalent.
select utl_raw.cast_to_varchar2(hextoraw(dbms_lob.substr(binary_entity)))
from content_collection;

[1]
http://confluence.sakaiproject.org/display/~ianeboston/Entity+Type1+Block+Encoding

On Mon, Feb 1, 2010 at 2:13 PM, Matt Hoyt <mrhoyt4 at yahoo.com> wrote:

> How do you read the contents of the Binary_Entity Column of
> Content_Resource table?
>
> --
> Matt Hoyt
>
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