Welcome to the magento community forum !
Well magento is built in open source technologies and framework like zend framework , symfony and at the core part its uses PHP.
So meaning its mainly support all the LAMP technologies , Coming back to your question Magento supports mainly MySql database but yes if your Sybase database have any connector or API then off course using that you can connect this Magento tool with that database
But direct use of Sybase Database is near to impossible !
Hope it helps !