The Format Conversion Approach

The NDF data access library follows this latter approach by allowing format conversion utilities to be added to it, thereby allowing it to access a range of ``foreign'' data (i.e. data which are not stored in the native NDF format). This has the following advantages:

• The full range of normal NDF data access operations can be supported - reading, writing, updating, deleting, reshaping, etc.

• Format conversion utilities can be added to already-built software. Thus you can add the ability to read new data formats to standard applications, without having to re-build them.

• Format conversion utilities can be written and added by anyone, so the problem of understanding and accessing a range of different formats can be shared. Particular problems can be tackled by whoever best understands them. This makes the NDF library capable of accessing data in formats completely unknown to its original author.

• Because it is easy to add new format conversion utilities, they do not always need to be very sophisticated. Instead, they can be invented or adapted to tackle new problems as they arise. Many of the difficulties encountered when converting a complicated data format into another one with a different data model can be ignored, unless they happen to be relevant to the situation at hand.

The main reason that this approach can be used is because of the relatively sophisticated formatting possibilities and data model presented by the NDF library, with its in-built extensibility. This makes it possible to convert foreign data into NDF format and back again without losing information, while the opposite process is not always possible.