Question

2. Consider the superclass/subclass hierarchical relationship: IT_Specialist (Partial, AND Databases Java UNIX PHP a) b) Describe two ways in which this model could be implemented in a relational database. Outline the benefits and disadvantages of each approach proposed in (a).

Answer 1

Ways of modeling in a relational database:

There are two ways in which the modeling of the above chart can be done using different techniques:

1. Single Table Inheritance:
   1. This is the model in which the inheritance can be made by mapping all the objects from different tables or database.
   2. It will lead to minimizing the joins that are included in the database so that we can quickly mount up the programs while processing for an inheritance structure in the multiple tables.
2. Class Table Inheritance:
   1. The class table inheritance is a method in which the object-relational mismatch can be used for creating relational databases.
   2. We will map all the different classes into different tables and access the data from each of the different tables whenever needed.
   3. This technique is a bit lengthy technique but is also an effective one.

Advantages & Disadvantages of approach:

The benefits of the approach are as follows:

• The method used above increases the reusability of the application code making it more flexible to change in terms of modules.
• It also increases the security of the code by hiding the data or using the encapsulation methods as used in the above methodology.
• It will also help in overriding the methods from the base class so that the implementation of the methods are meaningful and derived.

The disadvantages of the approach are as follows:

• It requires time and also a lot of effort is to be put in as it will require a lot of inherent things to be carved on.
• Maintaining the code in such terms is also challenging and can sometimes be too problematic.
• Adding new features in both the base as well as derived classes will do the complete change in the signature of both the classes which can also be problematic.

Hence, these are the benefits and disadvantages of the approach.