Abstract: An assembly module (201) is used to assemble complex objects from a plurality of objects stored on a disk of a server (80) in response to user queries in an object-oriented database executing in a client-server environment or multi-processor. Each complex object comprises a plurality of objects including a root object and a plurality of logically related sub-objects. Each object has an associated disk storage location, indicating where on the disk the object is stored. Each object may also include references to other objects. A list references to root objects of the complex objects needed to process a given query is provided in input list (202) to the assembly module (201) and stored in a reference list (204). A predetermined number of references in the reference list which are closest to the current disk head position are resolved into memory. Multiple objects are thus fetched from the disk in a single disk access.