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<h1>Blobs</h1>
<P>In some cases user has to deal with large binary objects (BLOBs) such as images, video, music, which should be stored in a structured way, and retrieved/queried easily. There are several challenges associated with this task:</P>
<UL>
<LI value="1"><span class="MCPopup"><a href="javascript:void(0);" class="MCPopupSpot" onclick="FMCPopup( event, this ); return false;" MadCap:src="../../configuration/file/storage.htm">Storage<img style="border: none;margin-left: 5px;" src="../../SkinSupport/ExpandingClosed.gif" MadCap:altsrc="../../SkinSupport/ExpandingOpen.gif" class="MCExpandingIcon" onload="if ( typeof( FMCPreloadImage ) == 'function' ) { FMCPreloadImage( '../../SkinSupport/ExpandingOpen.gif' ); }" /></a></span> location.</LI>
<LI value="2">Loading into Memory.</LI>
<LI value="3">Querying interface.</LI>
<LI value="4">Objects' modification.</LI>
<LI value="5">Information backup.</LI>
<LI value="6">Client/Server processing.</LI>
</UL>
<P>db4o provides you with a flexibility of using 2 different solutions for this case:</P>
<OL>
<LI value="1">The db4o blob-type.</LI>
<LI value="2">Byte[] arrays stored inside the database file</LI>
</OL>
<P>These two solutions' main features in comparison are represented below:</P>
<H2>Blob</H2>
<OL>
<LI value="1">Every Blob gets it's own file.</LI>
<LI value="2">Special code is necessary to store and load .</LI>
<LI value="3">No concerns about activation depth. </LI>
</OL>
<H2>byte[] array</H2>
<OL>
<LI value="1">Data in the same file </LI>
<LI value="2">Transparent handling without special concerns. </LI>
<LI value="3">Control over activation depth may be necessary</LI>
</OL>
<P>Storing data in a byte[] array works just as storing usual objects, but this method is not always applicable/desirable. First of all, the size of the db4o file can grow over the limit (256 GB) due to the BLOB data added. Secondly, object activation and client/server transferring logic can be an additional load for your application. </P>
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