As the paper declares the navigational Model encompasses the “network model” and “hierarchical model” of database interfaces. The network model was developed by Charles Bachman in 1971 to define and set a standard for database systems. This model had a collection of records, connected to each other through links. Various record types were interconnected to each other, thus allowing a many-to-many relationship. IDS and IDMS are both examples of the network model. A network model can be explained using this schematic diagram.
This discussion explores that navigational databases are open-ended and are best suited to handle small-scale data. However, it is difficult to search for data in this system since it does not have the search functionality. The system had to be navigated “manually”, that is to reach a particular record, one had to start at the parent record and then navigate step-by-step until one reaches the desired record. Due to these limitations, navigational database models became outdated by 1980s, though a form of the hierarchical model is still used in XML applications. The main distinguishing feature of the relational model is that the data is organized in a tabular form in rows and columns. The rows list the data while columns list the attributes. A key is chosen that uniquely identifies every row in the table and links different records from different tables. To find a particular set of data, a “query” is generated which mines the entire database to return the required answer. ...Show more