A method, comprising: upon startup of a database instance, registering all persistent classes of the database instance with an object management system, OMS, wherein each of the persistent classes is described by a corresponding application library; calling a constructor to register an interface for offering access to a description of the internal structure of at least one of the persistent classes, wherein the constructor provides an interface to disclosure code that is associated with the persistent class, wherein the disclosure code contains the description of the internal structure of the at least one of the persistent classes and wherein the interface is registered with the OMS and accessible to a database management system, DBMS, kernel; accessing, using the DBMS kernel, the registered interface to determine the internal structure of the persistent class; processing an instance of the persistent class based on the determined internal structure, wherein the instance of the persistent class is a persistent database object; defining an index associated with one or more members of the instance based on the determined structure; determining, based on the determined internal structure, members of the persistent database object that are filled with default values; storing the persistent database object in an object container of the database, the object container being associated with the persistent class; reducing storage demands on the database by removing the default values from the persistent database object before the storing of the persistent database object; after the storing of the persistent database object in the database, reading the persistent database object from the database; after the reading of the persistent database object from the database, populating the determined members of the persistent database object with the default values before transferring the persistent database object to a requesting application library 210; wherein the default values of the instance of the persistent class are determined based on the determined structure. upon startup of a database instance, registering all persistent classes of the database instance with an object management system, OMS, wherein each of the persistent classes is described by a corresponding application library; calling a constructor to register an interface for offering access to a description of the internal structure of at least one of the persistent classes, wherein the constructor provides an interface to disclosure code that is associated with the persistent class, wherein the disclosure code contains the description of the internal structure of the at least one of the persistent classes and wherein the interface is registered with the OMS and accessible to a database management system, DBMS, kernel; accessing, using the DBMS kernel, the registered interface to determine the internal structure of the persistent class; processing an instance of the persistent class based on the determined internal structure, wherein the instance of the persistent class is a persistent database object; defining an index associated with one or more members of the instance based on the determined structure; determining, based on the determined internal structure, members of the persistent database object that are filled with default values; storing the persistent database object in an object container of the database, the object container being associated with the persistent class; reducing storage demands on the database by removing the default values from the persistent database object before the storing of the persistent database object; after the storing of the persistent database object in the database, reading the persistent database object from the database; after the reading of the persistent database object from the database, populating the determined members of the persistent database object with the default values before transferring the persistent database object to a requesting application library 210; wherein the default values of the instance of the persistent class are determined based on the determined structure.