Institute of electrical and electronics engineers (IEEE)

         The Institute of Electrical and Electronics Engineers (IEEE) is a professional organization for electronic and electrical engineering (and related disciplines), with headquarters in New York City and an operations center in Piscataway, New Jersey. The American Institute of Electrical Engineers and the Institute of Radio Engineers merged in 1963 to form this organization.

        IEEE has a regional and technical structure that complements each other, with organizational units based on location and technical focus. It oversees a separate organizational entity (IEEE-USA), which makes policy recommendations and implements initiatives that benefit IEEE members, the profession, and the general public in the United States.

American national standard institute (ANSI)

 

    The American National Standards Institute (ANSI) is a private non-profit organization in the United States that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel.  In addition, the organization coordinates U.S. standards with international standards so that American products can be used globally.

    Standards developed by representatives of other standards organizations, government agencies, consumer groups, companies, and others are accredited by ANSI. These standards ensure that product characteristics and performance are consistent, that definitions and terms are used consistently, and that products are tested consistently. In addition, ANSI accredits organizations that perform product or personnel certification in accordance with international standards.

Networking Fundamental

     In Networking fundamental we study the building blocks of modern network design .Where we learn about the many different types of networks, networking concepts, network architecture, network communications and network design .

                                          

       Network is a group of two or more computer systems or other devices that are linked together to exchange data. Networks share resources, exchange files and electronic communications.

Why we study network fundamental?

    Network Fundamental is important to ensure that hardware and software can work together. Without Fundamental you could not easily develop a network to share information . Along with fundamental here are some standards that are categorized in two ways 

De facto

De jure

                            : Click standards to study network standards :

Networking Standards

Who creates a formal standards?

        An official industry or government group creates a formal standard. For example, formal standards exist for Web browsers (e.g., HTTP, HTML), network layer software (e.g., IP), data link layer software (e.g., Ethernet IEEE 802.3), and physical hardware (e.g., Ethernet IEEE 802.3). (e.g., V.90 modems).Formal standards take several years to establish, during which time technology evolves and makes them outdated.

 standards that are categorized in one of two ways 

De facto

    De facto refers to something that has happened in the past or is proven to be true. Without any formal planning, these standards are developed. Because of historical developments, these standards have emerged. Many organizations around the world continue to follow these guidelines. The widely accepted SNA is an example of this.

De jure

    De jure refers to a legal or regulatory framework. These standards were created after extensive research to meet the needs of data communication. The following are the major organizations that develop communication protocols and standards:

1. American national standard institute (ANSI)
2. Institute of electrical and electronics engineers (IEEE)
3. International standard organization (ISO)
4. International telecommunications union – telecommunication standards sector (itu-t)
5. The electronic industries association (EIA)

                                                :Click above for detail:

OOP

 What is OOP ?

        OOP stands for Object-oriented programming . the computer programming model based on the concept of "objects" . in OOP software is organized around data or object instead of function and logic .

        OOP focuses on the objects that developers want to handle rather than the logic required to handle them. This approach to programming is well-suited for programs that are large, complex and needs actively updates or to be  maintained. This includes programs for manufacturing and design, as well as mobile applications; for example, OOP can be used for manufacturing system simulation software.

        In OOP projects are divided into groups .plus benefits of OOP include code reusability, scalability and efficiency.

 The structure of object-oriented programming

The structure building blocks of object-oriented programming are  four as follows:

-  Classes

-  OBJECTS

-  Methods

-  Attributes / properties

• Classes are user-defined data types that act as the blueprint for individual objects, attributes and methods.
• Objects are instances of a class created with specifically defined data. Objects can correspond to real-world objects or an abstract entity. When class is defined initially, the description is the only object that is defined.
• Methods are functions that are defined inside a class that describe the behaviors of an object. Each method contained in class definitions starts with a reference to an instance object. Additionally, the subroutines contained in an object are called instance methods. Programmers use methods for reusability or keeping functionality encapsulated inside one object at a time.
• Attributes are defined in the class template and represent the state of an object. Objects will have data stored in the attributes field. Class attributes belong to the class itself.

There are four main principles of OOP:

1- Encapsulation.

2- Abstraction.

3- Inheritance. 

4- Polymorphism.

1- Encapsulation.

      This principle states that all important information is contained inside an object and only select information is exposed.

2- Abstraction.

     Objects only reveal internal mechanisms that are relevant for the use of other objects, hiding any unnecessary implementation code.

3- Inheritance.

     Classes can reuse code from other classes. Relationships and subclasses between objects can be assigned, enabling developers to reuse common logic while still maintaining a unique hierarchy.

4- Polymorphism.

     Objects are designed to share behaviors and they can take on more than one form. The program will determine which meaning or usage is necessary for each execution of that object from a parent class, reducing the need to duplicate code .

Popular pure OOP languages include:

• Ruby

• Scala

• JADE

• Emerald

Programming languages designed primarily for OOP include:

• Java

• Python

• C++

In any next blog we will Discuss about OOP benefits .

KEYS in RDBMS

 What are keys in DBMS ?

      A key in DBMS is an attribute or a set of attributes that help to uniquely identify a row in a relation of table. Keys are also used to create relationships between the different tables and columns of a relational database .

There are different types of keys as shown in above figure

Super Key

     A super key is a set of one or more attributes (columns), which can uniquely identify a row in a table. Super key is a superset of a candidate key.

FOR example:- 

  In EMPLOYEE table,  the name of two employees can be the same, but their EMPLYEE_ID can't be the same. Hence, The super key would be EMPLOYEE-ID.

candidate key

 A super key with no redundant attribute is known as candidate key . The remaining attributes except for primary key are considered as a candidate key. The candidate keys are as strong as the primary key.

FOR example:-

 In the EMPLOYEE table, id is best suited for the primary key. Rest of the attributes like SSN, Passport Number, and License Number, etc. are considered as a candidate key.

Primary key

  It is used to identify one and only one instance of an entity uniquely . It is a column or set of columns in a table that uniquely identifies rows in that table.

FOR example

In the EMPLOYEE table, ID can be primary key since it is unique for each employee. In the EMPLOYEE table, we can even select License Number and Passport Number as primary key since they are also unique.

Foreign key

  It is also like a primary key just the difference is that it is for the column. Foreign keys are the columns of a table that points to the primary key of another table. They act as a cross-reference between tables.

FOR example

  In a company, every employee works in a specific department, and employee and department are two different entities. So we can't store the information of the department in the employee table. That's why we link these two tables through the primary key of one table.

Composite key

   A key that has more than one attributes is known as composite key. It is also known as compound key. but when it taken individually it does not guarantee uniqueness. Composite key is a key which is the combination of more than one field or column in a table. It may be a candidate key or primary key.

FOR example

Alternate key

     A table can have many candidate keys. Among these candidate keys, only one key can be used as primary key a table can have multiple candidate keys. With these candidate keys, only one key gets selected as primary key, the remaining keys are known as alternative or secondary keys. key, the remaining keys are known as alternative or secondary keys.

FOR example 

 EMPLOYEE table can have the following attributes: 

Employee SSN: The SSN number of employees is stored in this field.

Employee Id: An attribute that stores the value of the employee identification number.

Employee name: An attribute that stores the name of the employee holding the specified employee id.

Employee email: An attribute that stores the email id of the specified employees.

CANDIDATE key will be as follows:

Employee SSN

Employee ID

Employee email

 From the above key only one can be selected as primary key and other two will be the alternate key

Employee ID will be the primary key (which we have discussed before)

other employee ID and employee email both will be used as alternate key .

" In this blog we have discussed six keys that are used at the basics " 

                E.R MODEL

E.R model stands for an Entity-Relationship model.ER model stands for an Entity-Relationship model. It works around real-world entities and the associations among them. At view level, the ER model is considered a good option for designing databases. (ER Modeling) is a graphical approach to database design.

 Entity

   An Entity is a thing or object in real world that is distinguishable from surrounding environment . An entity may be any object, class, person or place. In the ER diagram, an entity can be represented as rectangles.

    An Entity is an object of Entity Type and set of all entities is called as entity set . An entity set is a collection of similar types of entities. An entity set may contain entities with attribute sharing similar values.  

        For example:-

   A Students set may contain all the students of a school; likewise a Teachers set may contain all the teachers of a school from all faculties. Entity sets need not be disjoint.

Attributes

The attribute is used to describe the property of an entity. Attributes are the properties which define the entity type. For example, Roll No, Name, DOB, Age, Address, Mobile No are the attributes which defines entity type Student.

Types of Attributes

• Simple attribute − Simple attributes are atomic values, which cannot be divided further. For example, a student's phone number is an atomic value of 10 digits.

• Composite attribute − Composite attributes are made of more than one simple attribute. For example, a student's complete name may have first_name and last_name.

• Derived attribute − Derived attributes are the attributes that do not exist in the physical database, but their values are derived from other attributes present in the database. For example, average salary in a department should not be saved directly in the database, instead it can be derived. For another example, age can be derived from data_of_birth.

• Single-value attribute − Single-value attributes contain single value. For example − Social_Security_Number.

• Multi-value attribute − Multi-value attributes may contain more than one values. For example, a person can have more than one phone number, email_address, etc.