Navigationless, Navigational and the Newer Interactive Navigational Database Access
There is a newer type of database navigation on the market that is also referred to as navigational but is quite different than the currently understood meaning of navigational data access. I call this newer type of navigation interactive navigational access and compare its operation to the other types of navigation below.
Navigationless access is the ability of the database software to access the database without the user having to instruct the application on how to access the required data. This is specified at a nonprocedural level where the user’s query indicates what data is needed and not how to locate it. Navigational access requires the user to specify a series of step-by-step instructions on how to locate the desired database at a low level procedural level. Navigational processing requires control of the access operation. There is a relatively newer access operation which is also referred to as navigational processing which is actually controlled at a high nonprocedural level where high level controlled access through the database is necessary but low level procedural access is not necessary. This is done by the user stating where in the database to go next and the database system takes care of the low level navigation to get there automatically. This process is interactively progressed continuing through the database from one place in the database to any other without requiring low level navigation.
Navigationless Access
Navigationless database processing is possible when the hierarchical data structure is structured, well behaved, unambiguous, and its data structure is known. In this way the system can perform the entire query automatically. All of the navigation is performed automatically. The system decides in what order the required data items are processed in order to process the query in the most efficient way.
Navigational Access
Navigational procedural access is necessary when data is semistructured, its structure is dynamic and ambiguous for automatic querying with multiple nodes with the same name. Because of this the system needs to be instructed at a low level step-by-step procedural manner on how to access the required data.
Interactive Navigational Access
Interactive navigational access is a combination of navigationless and navigational access with the benefits of both. It allows the user to move quickly and nonprocedurally to any specific position in the database and then depending on the data at that location to decide to follow the trail to another place in the database. This traveling between desired destinations in the database is performed at a high nonprocedural level but maintains procedural control of the higher level database application logic. While navigationless queries specify all of the query information in a single query, interactive navigational access must follow the data clues in the database, but can perform this at a high navigationless level which is still navigational at a higher conceptual level.