Notes with worthy tutorials
Database Language: As whatever we want to be manipulated by computer has to be written using specific language, database is not beyond them. To write or create database management system we use database languages. They are of two types; Data Definition Language (DDL) and Data Manipulation Language (DML). DDL is used to design a database … Read more
Data Model: Data model is the structure of the database, which is a collection of conceptual tools for describing data, data relationships, data semantics and consistency constraints. The data models can be classified into the following four categories. Relational Model: The relational data model uses a collection of tables to represent both data and the … Read more
Instances: A database is generally used by many users where insertion and deletion of data occurs frequently. Overall information stored in a database at a particular moment is called the instance of the database. Schemas: The overall design of a database which includes the data structures, table designing and relation of data from table to … Read more
Data Abstraction: Different users require different view of the database which is useful and necessary to them. This is data abstraction by which we abstract useful data from a database for a particular type of users to use. There are 3 levels of data abstraction, those are as follows; Physical Level: The lowest level of … Read more
Disadvantages of File Processing System: Keeping organization information in a file processing system has some disadvantages including the followings, Data Redundancy & Inconsistency: As the files are created by different programmers, there is a huge chance of data redundancy which is responsible for unnecessary storage and access cost. This may also lead to data inconsistency … Read more
Applications of DBMS: DBMS is getting used in many places. Everything from file cabinets to dictionaries is disappearing from today’s working place, because it is easy to make use of the data using a DBMS. The uses or applications of DBMS include the following, In Banking: For customer information, accounts, loans and banking transactions. This … Read more
Database: A database contains a collection of related items or facts arranged in a specific structure. The most obvious example of a non-computerized database is a telephone directory. DBMS (Database Management System): A database management system is a collection of interrelated data and a set of programs to access those data. It allows people to … Read more
A static keyword is very important in object oriented programming. Static methods and properties play a vital role in application design and also in design patterns. So what are static methods and properties? In general, to access any properties or method of a class we first have to initialize an object of that class. Then … Read more
Wavelet: Wavelets are tiny parts of waves. Secondary wavefront: The envelop of all the secondary wavelets in the forward direction is called the secondary wavefront. The backward envelop is not a secondary wavefront.
Wavefront A wavefront can be defined as the locus of all the points of the medium which are vibrating in phase and are also displaced at the same time. If the distance of the source is small the wavefront is spherical. But when the distance is large then any small portion of the wavefront can … Read more