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DATA MODEL

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 DATA MODEL It is a conceptual tools which describe logical design of a database. It define entity definations, relationship and symmentic properties of intigrity constant. The very first data model could be flat data-models, where all the data used are to be kept in the same plane. Earlier data models were not so scientific, hence they were prone to introduce lots of duplication and update anomalies.  While the  Relational Model  is the most widely used database model, there are other models too: Hierarchical Model Network Model Entity-relationship Model Relational Model Hierarchical Model This database model organises data into a tree-like-structure, with a single root, to which all the other data is linked. The heirarchy starts from the  Root  data, and expands like a tree, adding child nodes to the parent nodes. In this model, a child node will only have a single parent node. This model efficiently describes many real-world relationships like index of a book, recipes etc. In hierar
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ENTITY In DBMS

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  ENTITY  An entity is a object which differenciate from another object in the real world. For eg:  employee,customer,doctor,patient all those are entity. Entity is a set of attribute.Attribute is a field which describe the description property of entity. A set of some type of entity is called  entity set. ROLE OF DBMS One of the main reason for having DBMS is to have control of both data and program execessing that data.The DBMS as a person or program having such control over thr system. The main role of DBA: 1.Schema defination The creation of the original database schema by writting a set of defination which are translated by the DDL compilar(Data Defination Language) to a set of table that are permanently stored in the data dictonary. 2.Storage Structure and access method defination. The creation of appropriate and excess method by writting a set of definitions which are translated by the data storage and defination language compiler. 3.Schema and Physical organisation modification
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DBMS

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  DBMS (Database Management System) DBMS stands for Database Management System. We can break it like this DBMS=Database+ Management System. Database is a collection of data and management system is a set of programs to store abd retrieve those data. Based on this we can define DBMS like this: DBMS is a collection of inter-releted data and set of programs to store and access those data in an easy and effective those data in an easy and effective manner. The main characteristics of database system: 1.It provide to create, modify and remove the database. 2.To store new information, to change (update) existing information and remove(delete) information. 3.It provides data manipulation using mathematical and logical operator. 4.It provides to generate various report(permanentiy)/adhoc(temporary). 5.It provide data integrity. What is the need of DBMS? Database Systems are basically developed for large amount of data.When dealing with huge amount of data, there are two things that require opt
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C++ Inheritance

 Inheritance Inheritance is the mechanism in which new class adopt the properties of the old class. It is the capability of a class to derive properties and characteristics from another class. Inheritance is one of the most important feature of object oriented programming. The derive class inherited the features of the base class and can have additional features of its own.  Inheritance is an "is a" relationship. We use Inheritance only if an is a relationship is present between two classes. Here, are some examples- A car is a vehicle. Car----derive class Vehicle----base class The main advantages of inheritances are code reusability and readability when child class inherit the properties of functionality of parent class, we need not to write the properties of functionality of parent class, we need not to write the same code again in child class.
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C++ class

  C++ Class Definitions A class has a class name, a set of attributes (data members and characteristics) and a set of actions or services. Class is an explicit datatype. The class specified the type and scope of variables and functions declared inside the class. The variables declared inside the class are known inside the class are known as data member or menber variables and the functions are called member functions. The body of the class is enclosed within braces and terminated by the semicolon. The keyboards private, public and protected are known as visibility levels, which defines the visibility of member.    A C++ class is like a blueprint for an object. A Class is a user defined data-type which has data members and member functions. Data members are the data variables and member functions are the functions used to manipulate these variables and together these data members and member functions defines the properties and behavior of the objects in a Class. In the above example of
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History of C++

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HISTORY History of  C++ language is interesting to know. Here we are going to discuss brief history of C++ language. C++ programming language  was developed in 1980 by Bjarne Stroustrup at bell laboratories of AT&T (American Telephone & Telegraph), located in U.S.A. Bjarne Stroustrup  is known as the  founder of C++ language.                   SOME FACTS ABOUT C++ 1.C++ development began in 1979, four years before its release, and it did not start with the name C++; Its first name was  C with classes . 2.In the late part of 1983, C with Classes was first used for AT&T's internal programming needs. 3.Its name was changed to C++ later in the same year. 4.C++ was not released commercially until the late part of 1985. C++ implements  data abstraction  using a concept called  classes , along with other features to allow  object-oriented programming  and is considered a  high-level language . Classes help programmers with the organization of their code. They can also be benef
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Database system

  Database System A database system is a collection of data which fulfill the user requirement or solve the purpose for various user in a particular applications. The main characteristics of database system- It is integrated and it is shareable. The basic function or database system or facilities are: (1). It provide to create, modify and remove the database. (2). To store new information, to change (update) existing information  and remove (delete) information. (3). It provides data manipulation using mathematical and logical operator. (4). It provides to generate various report (permanently)/ adhoc (temporary). (5). It provides data integrity.
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