Hierarchical Database Model – In hierarchical database model, data is structured in hierarchical form and is characteristically presented in the form of inverted table (Gillenson et al, 2008). Hierarchical database relationship is represented in the form of parent and child relation. This sort of relationship comprises of table with parent table which can be linked with child tables, however one child table can form linkage to single parent table only. Such tables are unequivocally connected through either a pointer or physical array of the table records.
Network Database Model – In several ways, the network database model looks like the hierarchical database model. However, unlike hierarchical model, a network model’s record can have two or more parent. In network database model, set is the name for the relationship. Each set comprises of minimum records of two types, hierarchical database model’s parent or owner and a hierarchical database model’s child or member record. The difference between the hierarchical and network database model is that the latter might include a condition in which a member can appear in more than one set (Blattberg et al, 2008). A set corresponds to a one-to-many relationship connecting owner of the table and the member of table.
Relational Database Model – The relational database model performs the basic functions of network and hierarchical model along with other additional functions that make the relational database model easier to understand and implement. The most important advantage of this model is that it allows the user to operate with human logical environment. This model is perceived by the user to be an assortment of tables to store the data. Each of the tables is in the form of matrix comprising of row and columns. Tables are called relations and are related by common entity attributes. Relational table gathers an assortment of correlated entities. In this aspect, the table of relational database is similar to a file.
In the given scenario, Fernando wants the supplier to be linked with product table wherein the supplier would be the parent or owner record and the product would be child or member. Since, one supplier can provide the product provided by another supplier also, the table would have the characteristics of network table also. The supplier table and product table would be linked through relational database design method as the information related to the product would be common in the two tables. The assumption is that one supplier provides one type of product.
The above tables on supplier and product have a common link Product Code which enables one to match the supplier to its product, even though the supplier data is stored in one table and the product data is stored in another table. Fernando can easily determine that product Sufy with price of $1,000 is supplied by Le Grand supplier. Though the tables are completely independent to each other, they can easily be connected through the relational data.
Mark L. Gillenson, Paulraj Ponniah, Alex Kriegel, Boris M. Trukhov, Allen G.Taylor. (2008). Introduction To Database Management. Wiley.
Robert C. Blattberg, Pyŏng-do Kim, Byung-Do Kim, Scott A. Neslin. (2008). Database marketing: analyzing and managing customers. Springer.