Direct loading of opaque types

Techniques and systems are disclosed for storing instances of an opaque type in a database according to a direct path loading approach. According to one aspect, an opaque type implementor registers, with a loader application, routines that the opaque type implementor implements. In response, the loader application associates the opaque type with the routines. The loader application reads data that comprises instances of the opaque type. The loader application determines which routines are associated with the opaque type. The loader application invokes the routines, which create an array for storing instances of the opaque type and populate the array with values specified in the data. The loader application converts the array into a data stream that conforms to the format of the database's data blocks. The loader application then streams the data to a database server, which writes the data directly into data blocks in the database.