Table 2 The relationship between the development of systems to support a data standard and the different modelling structures that could be used: NVT (Name-value-type), ontologies, external files and extend model inheritance (EMI).
From: An analysis of extensible modelling for functional genomics data
Extension | Support for task: Modelling |
|---|---|
NVT | Near zero cost. |
Ontology | Expensive (hard to develop ontology). |
External file | No cost. |
EMI | Fairly high cost because additional modelling in advance and the developer must understand the core model and how it can be extended. |
Extension | Support for task: Interface (for populating) |
NVT | Fairly easy as the code need not reflect the attributes, but difficult to ensure consistency as there is no explicit prompting from a controlled vocabulary. |
Ontology | Some additional costs (importing ontology or calling an ontology service) |
External file | Very easy (just upload the file). |
EMI | Changes required to the interface to reflect the extensions unless the interface is created automatically from the model. |
Extension | Support for task: Interface (for query/browse) |
NVT | Few additional costs as the interface code need not reflect the attributes. |
Ontology | Low cost as the queries can be generated from the model and ontology. |
External file | The default is no functionality over the file otherwise extra coding is required which may be relatively costly. |
EMI | Additional costs as interface code must be written to cover the extension unless the interface is generated from the model. |
Extension | Support for task: Data management |
NVT | Low cost as no changes are required to the schema. |
Ontology | No changes to database schema but small additional costs because the ontology has to be stored locally or linked externally. |
External file | No changes required to the schema but small additional cost because more than one storage mechanism must be managed (database and file system). |
EMI | Changes are required to the schema, which are likely to be expensive. |
Extension | Support for task: Quality assurance |
NVT | None; terms should be used with caution. NVT cannot restrict the cardinality or possible values. |
Ontology | Good because a domain value can be enforced. |
External file | No constraint or value checking. |
EMI | Some quality enforcement because there will be guidelines as to the types of extensions allowed to a model and the model will enforce constraints on the value stored. |