The systems that are used to organize and maintain data files are known as file based data systems. These file systems are used to handle a single or multiple files and are not very efficient. FunctionalitiesThe functionalities of a File-based Data Management System are as follows −A file based system helps in basic data management for any user.The data stored in the file based system should remain consistent. Any transactions done in the file based system should not alter the consistency property. The file based system should not allow any illegal or potentially hazardous operations to occur on the data.The file based ... Read More

A database is a collection of data, usually stored in electronic form. A database is typically designed so that it is easy to store and access information.A good database is crucial to any company or organisation. This is because the database stores all the pertinent details about  the company such as employee records, transactional records, salary details etc.The various reasons a database is important are −Manages large amounts of dataA database stores and manages a large amount of data on a daily basis. This would not be possible using any other tool such as a spreadsheet as they would simply ... Read More

Spatial data is associated with geographic locations such as cities, towns etc. A spatial database is optimized to store and query data representing objects. These are the objects which are defined in a geometric space.Characteristics of Spatial DatabaseA spatial database system has the following characteristicsIt is a database systemIt offers spatial data types (SDTs) in its data model and query language.It supports spatial data types in its implementation, providing at least spatial indexing and efficient algorithms for spatial join.ExampleA road map is a visualization of geographic information. A road map is a 2-dimensional object which contains points, lines, and polygons ... Read More

Data WarehousingData warehousing is a collection of tools and techniques using which more knowledge can be driven out from a large amount of data. This helps with the decision-making process and improving information resources. Data warehouse is basically a database of unique data structures that allows relatively quick and easy performance of complex queries over a large amount of data. It is created from multiple heterogeneous sources.Characteristics of Data WarehousingIntegratedTime variant Non-volatileThe purpose of Data warehouse is to support the decision making process. It makes information easily accessible as we can generate reports from the data warehouse. It usually contains historical data ... Read More

The Enhanced Entity Relationship Model contains all the features of the Entity Relationship model. In addition to all that, it also contains features of Subclasses, Superclasses and Inheritance.All of these in detail are as follows −SubclassesA subclass is a class derived from the superclass. It inherits the properties of the superclass and also contains attributes of its own. An example is:Car, Truck and Motorcycle are all subclasses of the superclass Vehicle. They all inherit common attributes from vehicle such as speed, colour etc. while they have different attributes also i.e Number of wheels in Car is 4 while in Motorcycle ... Read More

Class hierarchy can be viewed one of two waysSpecialization (Top Down Approach)Generalization (Bottom Up Approach)SpecializationSpecialization is a process of identifying subsets of an entity that shares different characteristics. It breaks an entity into multiple entities from higher level (super class) to lower level (subclass). The class vehicle can be specialized into Car, Truck and Motorcycle ( Top Down Approach)Hence, vehicle is the superclass and Car, Truck, Motorcycle are subclasses. All three of these inherit attributes from vehicle. Moreover, these three share those attributes among themselves while containing some other attributes which make them different.GeneralizationGeneralization is a process of generalizing an entity which ... Read More

The detailed comparison on the E- R model and Object Oriented Model is given as follows −E-R ModelER model is used to represent real life scenarios as entities. The properties of these entities are their attributes in the ER diagram and their connections are shown in the form of relationships. An ER model is generally considered as a top down approach in data designing.An example of ER model is −Advantages of E - R modelThe data requirements are easily understandable using an E - R model as it utilises clear diagrams.The E-R model can be easily converted into a relational database.The ... Read More

In object based data models, the focus is on how data is represented. The data is divided into multiple entities each of which have some defining characteristics. Moreover, these data entities are connected with each other through some relationships.So, in object based data models the entities are based on real world models, and how the data is in real life. There is not as much concern over what the data is as compared to how it is visualised and connected.Some examples of object based data models areEntity Relationship Data ModelObject Oriented Data ModelSemantic Data ModelFunctional Data ModelOut of these models, ... Read More

ER model is used to represent real life scenarios as entities. The properties of these entities are their attributes in the ER diagram and their connections are shown in the form of relationships.Some examples of ER model are −Hospital ER ModelThis is an ER model of a Hospital. The entities are represented in rectangular boxes and are Patient, Tests and Doctor.Each of these entities have their respective attributes which are −Patients - ID(primary key), name, age, visit_dateTests- Name(primary key), date, resultDoctor- ID(primary key), name, specializationThe relationships between different entities are represented by a diamond shaped box.Company ER ModelThe entities in this ... Read More

An entity is similar to a unique object and a collection of attributes. There are two types entities namely strong entity and weak entity. A strong entity is an independent entity. On the other hand, a weak entity is a dependent entity that depends on a strong entity. Read through this article to find out more about strong and weak entities and how they are different from each other. What is a Strong Entity? A strong entity is complete by itself and is not dependent on any other entity type. It possess a primary key which describes each instance in ... Read More