Compiler: - a compiler is not one piece of software. It starts out with a lexical, then a parser … and ends with the assembly code which the linker takes to map virtual add to the physical addresses. So, basically, it’s a tool which checks for syntax and semantics of a language, creates the code readable by the machine.

A compiler is a specialized computer program that converts source code written in one programming language into another language, usually machine language (also called machine code) so that it can be understood by processors (i.e., logic chips).

Source code is the version of software (usually an application program or an operating system) as it is originally written (i.e., typed into a computer) by a human in plain text (i.e., human readable alphanumeric characters).

First was machine code: – first programs written directly in the hardware’s machine code

Then was assembler: – A program written in machine code to interpret asm into machine code.

Then was a compiler: – A set of programs (lexical analyser, parser linker etc) which could convert source code to assembler/machine code.

 The “first” compiler was created by Rear Admiral Dr. Grace Murray Hopper in 1949. The compiler, written in assembly language, converted symbolic mathematical code into machine code.

By 1949 programs contained mnemonics that were transformed into binary code instructions executable by the computer. Admiral Hopper and her team extended this improvement on binary code with the development of her first compiler, the A-O. The A-O series of compilers translated symbolic mathematical code into machine code, and allowed the specification of call numbers assigned to the collected programming routines stored on magnetic tape. One could then simply specify the call numbers of the desired routines and the computer would “find them on the tape, bring them over and do the additions. This was the first compiler,”

It should be pointed out that the original ‘compilers’ were closer to what we would today call a linker, i.e., a tool for combining existing libraries into a program. The name came from the fact that they ‘compiled’ the libraries into a single binary image.

Admiral Hopper believed that the major obstacle to computers in non-scientific and business applications was the dearth of programmers for these far from user-friendly new machines. The key to opening up new worlds to computing, she knew, was the development and refinement of programming languages – languages that could be understood and used by people who were neither mathematicians nor computer experts. It took several years for her to demonstrate that this idea was feasible.

This is 21 century. We are living an era called information era. All information stores in digital device that understand o or 1 binary digit. All Information is store in name called database. Creating your own database and running SQL query itself was a challenged. But when ZOHO come into the picture it makes our life easy. It not only provides us creating your own online database and query but also make it very simple.

There are some steps to follow create and run this data base.

Go to the website and create an your own user account in www.db.zoho.com

Then create a database by any of the four options displayed i.e. import via excel sheet, enter data right away, create database from template, create blank database. Then name the tables (in my case EMPLOYEE & DEPARTMENT).

If you need to change some characteristic of Table you can do it after creating it.

Now run SQL query according to your need.

According to my database three SQL queries were run and thus three query tables (views) were generated namely JOIN, AVERAGE QUERY & CONDITIONS. But the main issue is ‘How to run a query? Earlier if you want to run and use SQL database you need to have SQL database knowledge. But ZOHO platform make this complicated system to simple. Now it becomes easy to create, delete update and query of SQL database. Here one can write query functions and can also have SQL functions (table and column name) from the box besides query writing area.

There are three query tables one is for joining the tables and the syntax is

Select “Employee_id”,”First Name”,”Last Name”, “Salary”,”Commision”, “Salary”

+”Commision”*”Salary” from”EMP” where “Depart_ment” = ‘SALES

Here

EMP=Employee

DEPT=Department

SQL query for getting average salary of the firm’s employee. This is in average value of salary in Employee table.

Syntax for this SQL query is

Select AVG(“Salary”) from”EMP”;

Select max(“Salary”) from”EMP”;

Select SUM(“Salary”) from”EMP”;

Here it generate the average salary of employee from employee table

This gives the average of the values of the column chosen. This is a multiple row function. Accordingly there are other functions also such as sum, max, etc.

SQL query for various restrictions such as OR, AND, wild cards is to obtain constrained view.

Next are

Select “Employee_id” , “First Name” ,”Last Name” from “EMP” where (“First Name”=’Abu’ OR “First Name”=’Faizan’ or “First Name” like ‘D%’)

This gives the customized view of the database. Here according to the command the three respective columns are selected. Which are encompassed through restrictions that are elements of first name are equal to two of the identified elements of first names? Means only those rows are selected which have identified elements in them. Also column name1 which is ‘name’ is subjected to constrain that name should start with ‘A’.

Select “Employee_id”, “Last Name”,”First Name”, “Location” from EMP”, “DEPT” where “EMP”.”Employee_id” = “DEPT”.”E_id”

In this SQL query three commend very important and it uses are most of time the command is ‘select’, ‘delete’ and ‘update ’.

Limitation of db.zoho.com is that only SELECT query can run.

To see Query tables please go to the link mention below:

http://db.zoho.com:80/ZDBDataSheetView.cc?OBJID=24430000000004401&STANDALONE=true

http://db.zoho.com:80/ZDBDataSheetView.cc?OBJID=24430000000004310&STANDALONE=true

http://db.zoho.com:80/ZDBDataSheetView.cc?OBJID=24430000000004963&STANDALONE=true

http://db.zoho.com:80/ZDBDataSheetView.cc?OBJID=24430000000004932&STANDALONE=true

http://db.zoho.com:80/ZDBDataSheetView.cc?OBJID=24430000000004876&STANDALONE=true

http://db.zoho.com:80/ZDBDataSheetView.cc?OBJID=24430000000004760&STANDALONE=true

http://db.zoho.com:80/ZDBDataSheetView.cc?OBJID=24430000000004635&STANDALONE=true

Students                                                                 

student_id                                                                                                                                                                                                                   

students_name    

students_address

email_address  

other_students_deatils