CREATE TABLE Statement

 

CREATE TABLE Statement

A Table is a combination of rows and columns. For creating a table we have to define the structure of a table by adding names to columns and providing data type and size of data to be stored in columns.

Syntax:

CREATE table table_name(

Column1 datatype (size),

column2 datatype (size),

.

.

columnN datatype(size)

); 

CREATE TABLE Customer(
    CustomerID INT PRIMARY KEY,
    CustomerName VARCHAR(50),
    LastName VARCHAR(50),
    Country VARCHAR(50),
    Age int(2),
  Phone int(10) 

); 

Basic Python Tutorial

                                            

• Introduction

• History of Python

• Features of Python

•  Advantage of Python

• Basic Syntax of Python

• Rules of Variable in Python

 

Boolean Algebra

Boolean algebra is the branch of algebra in which the values of the variables are the truth values true and false. Mathematician George Boole Invented a new kind of algebra- the algebra of logic in the year 1854 popularly known as Boo

lean Algebra or Switching Algebra. Boolean algebra can be used to simplify the design of logic circuits. This method perform mathematical operation. An alternative method called the Karnaugh map can be used for the simplification of Boolean equations with up to four input variables.

Basic Laws of Boolean Algebra

• Boolean Addition (OR Operation)

Boolean method involves variables having values of either a binary  1 or 0. The basic rules of Boolean addition are given below:

0+0 = 0

0+1= 1

1+0= 1

1+1= 1

• Boolean Multiplication (AND Operation)

The basic rules of the Boolean multiplication method are as follows:

0.0 = 0

0.1= 0

1.0= 0

1.1= 1

 

Control Structures in Programming Languages

Control Structures are  a way to specify flow of control in programs.  It basically analyzes and chooses in which direction a program flows based on certain parameters or conditions. There are three basic types of logic, or flow of control

1. Sequential flow
2. Conditional flow
3. Iteration flow

1. Sequential Logic (Sequential Flow)

Sequential logic as the name suggests follows a serial or sequential flow in which the flow depends on the series of instructions given to the computer. Unless new instructions are given, the modules are executed in the obvious sequence. The sequences may be given, by means of numbered steps explicitly. Also, implicitly follows the order in which modules are written. Most of the processing, even some complex problems, will generally follow this elementary flow pattern.

Conditional Flow

In this flow structure instructions are proceed on this basis of given conditions.  The structures which use these type of logic are known as Conditional Structures. These structures can be of three types:

• Single Flow (Only If)

  If (condition) then:
       [Module A]   
  [End of If structure]

Double Flow (If... Else....)Structure

If (Condition), then:
     [Module A]
Else:
     [Module B]
[End if structure]

C Language

 

Introduction of C Language

C is a general-purpose, procedural programming language. It was initially developed by Dennis Ritchie in the year 1972 at the Bell Telephone Laboratories . It was mainly developed as a system programming language to write an operating system. The main features of C language include low-level access to memory, a simple set of keywords, and clean style, these features make C language suitable for system programmings like an operating system or compiler development.

Basic Function of C Language

C programming language is a MUST for students and working professionals to become a great Software Engineer specially when they are working in Software Development Domain. I will list down some of the key advantages of learning C Programming:

• Easy to learn

• Structured language

• It produces efficient programs

• It can handle low-level activities

• It can be compiled on a variety of computer platforms

Facts about C

• C was invented to write an operating system called UNIX.

• C is a successor of B language which was introduced around the early 1970s.

• The language was formalized in 1988 by the American National Standard Institute (ANSI).

• The UNIX OS was totally written in C.

• Today C is the most widely used and popular System Programming Language.

• Most of the state-of-the-art software have been implemented using C.

History of C Programming

The C programming language came out of Bell Labs in the early 1970s. According to the Bell Labs paper The Development of the C Language by Dennis Ritchie, “The C programming language was devised in the early 1970s as a system implementation language for the nascent Unix operating system. Derived from the  language BCPL, it evolved a type structure; created on a tiny machine as a tool to improve a meager programming environment.” Originally, Ken Thompson, a Bell Labs employee, desired to make a programming language for the new Unix platform. Thompson modified the BCPL system language and created B. However, not many utilities were ever written in B due to its slow nature and inability to take advantage of PDP-11 features in the operating system. This led to Ritchie improving on B, and thus creating C.

Language	Year	Developed By
Algol	1960	International Group
BCPL	1967	Martin Richard
B	1970	Ken Thompson
Traditional C	1972	Dennis Ritchie
K & R C	1978	Kernighan & Dennis Ritchie
ANSI C	1989	ANSI Committee
ANSI/ISO C	1990	ISO Committee
C99	1999	Standardization Committee

Features of C Language

C is the widely used language. It provides many features that are given below.

1. Simple
2. Machine Independent or Portable
3. Mid-level programming language
4. structured programming language
5. Rich Library
6. Memory Management
7. Fast Speed
8. Pointers
9. Recursion
10. Extensible

Flow Control Structure of Programming

Control Structure

SQL (Structure Query Language)

What is SQL?

SQL stands for Structured Query Language. SQL became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987.

SQL is Structured Query Language, which is a computer language for storing, manipulating and retrieving data stored in a relational database.

Applications of SQL

SQL is one of the most widely used query language over the databases. I'm going to list few of them here:

·        Allows users to access data in the relational database management systems.

·        Allows users to describe the data.

·        Allows users to define the data in a database and manipulate that data.

·        Allows to embed within other languages using SQL modules, libraries & pre-compilers.

·        Allows users to create and drop databases and tables.

·        Allows users to create view, stored procedure, functions in a database.

·        Allows users to set permissions on tables, procedures and views.

SQL Commands

1.   DDL - Data Definition Language

• CREATE
• ALTER
• DROP

2.     DML - Data Manipulation Language

·        SELECT

·        INSERT

·        UPDATE            

·        DELETE

3.     DCL - Data Control Language

·        GRANT

·        REVOKE

4.   TCL – Transaction Control Language

• COMMIT
• ROLLBACK
• SAVEPOINT

Data Integrity

The following categories of data integrity exist with each RDBMS −

• Entity Integrity − There are no duplicate rows in a table.

• Domain Integrity − Enforces valid entries for a given column by restricting the type, the format, or the range of values.

• Referential integrity − Rows cannot be deleted, which are used by other records.

• User-Defined Integrity − Enforces some specific business rules that do not fall into entity, domain or referential integrity.

SQL Constraints

Constraints are the rules enforced on data columns on a table. These are used to limit the type of data that can go into a table. This ensures the accuracy and reliability of the data in the database.

Constraints can either be column level or table level. Column level constraints are applied only to one column whereas, table level constraints are applied to the entire table.

Following are some of the most commonly used constraints available in SQL −

 

• NOT NULL Constraint − Ensures that a column cannot have a NULL value.

• DEFAULT Constraint − Provides a default value for a column when none is specified.

• UNIQUE Constraint − Ensures that all the values in a column are different.

• PRIMARY Key − Uniquely identifies each row/record in a database table.

• FOREIGN Key − Uniquely identifies a row/record in any another database table.

• CHECK Constraint − The CHECK constraint ensures that all values in a column satisfy certain conditions.