Object relational mapping layer

An integration server system, comprising:

• a processor that executes instructions stored in a data storage medium;
• a database that stores data accessible to the processor;
• a generator that creates a database schema in response to a model description, the database schema including at least one table and configured to store a set of data object instances in the database;
• a metadata model representing a configuration of the set of data object instances in the database schema;
• a model application programming interface that provides a client application with access to the set of data object instances as separate data objects and that converts the set of data object instances into one of at least two different object formats based on requirements of the client application, whereby the client application is able to access data for use in executing a process for the client application;
• and
• a metadata application programming interface that provides a client application with access to definitions for the set of data object directly within the database schema instances via the metadata model, the client creating and updating data objects by modifying metadata for the set of object instances without accessing the data object instances through the model application programming interface,
• wherein the database schema utilizes an ordered sequence for preserving an ordered association between the set of data object instances, a random sequence value being generated for a new data object instance to be inserted into the ordered sequence, the random sequence value being generated relative to an average of sequence values of existing data object instances immediately adjacent to a point of insertion in the ordered sequence, the generation of a random sequence value enabling the client application and any additional application able to concurrently insert a data object instances into the ordered sequence.