GN4 is based on a single relational database holding all the data structures and configuration information – plus (optional) file storage to hold large binary data files (e.g. ,images, multi-media etc.).

The structure of this database is not fixed, but it is completely definable and can be modified at any time using a standard XML schema (XSD).  More precisely: there is a small set of pre-defined tables, but the bulk of the database – and all the actual data – is user-definable through the schema.

The data contained in the system are organized as ‘objects’ –  images, texts, videos, documents, folders, users, etc. Objects correspond to XML elements declared in the schema. Loading the schema into the database automatically creates the tables and cross references to manage the defined object types.

The schema can be modified and re-imported at any time, allowing the data model to be changed on the fly. For example, adding new metadata to existing objects, or add entirely new object types.

The schema also controls the built-in data structures such as users, groups, access permissions, application configuration and so on. This means that it is possible to customize system data structures. For example, add new fields to the user’s description, and specify how the access to that object is controlled.

 

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