Homework week 2 : introduction to SQL on website tutorial

Introduction to SQL on w3school website tutorial 

 

          In this website we can learn about SQL language for accessing or query databases in database management system (DBMS)

1. SQL Home 

 

          This topic will tell me about SQL tutorial will teach us how to use SQL to access and manipulate data in: MySQL, SQL Server, Access, Oracle, Sybase, DB2, and other database systems. It has online SQL editor that can try edit the SQL statements, and click on a button to view the result. in example

          We can try the statment SELECT * FROM Customers; and click run the result, you can see the example of database in this website so this statement is select for see everything of your database.

            in addition, we can do the test , datatype and ranges for Microsoft Access, MySQL and SQL Server, reference and exam.

2. Introduction to SQL

 

          In this topic we can learn about the description of SQL language. SQL is a standard language for accessing and manipulating databases.

- What is SQL?

• SQL stands for Structured Query Language
• SQL lets you access and manipulate databases
• SQL is an ANSI (American National Standards Institute) standard

- What Can SQL do?

• SQL can execute queries against a database
• SQL can retrieve data from a database
• SQL can insert records in a database
• SQL can update records in a database
• SQL can delete records from a database
• SQL can create new databases
• SQL can create new tables in a database
• SQL can create stored procedures in a database
• SQL can create views in a database
• SQL can set permissions on tables, procedures, and views

- RDBMS

           RDBMS stands for Relational Database Management System.
RDBMS is the basis for SQL, and for all modern database systems such as MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access.
           The data in RDBMS is stored in database objects called tables.
A table is a collection of related data entries and it consists of columns and rows.
So to build a web site that shows data from a database, you will need:

• An RDBMS database program (i.e. MS Access, SQL Server, MySQL)
• To use a server-side scripting language, like PHP or ASP
• To use SQL to get the data you want
• To use HTML / CSS

3. SQL Syntax

 

- Database table   

           Each table is identified by a name (e.g. "Customers" or "Orders"). Tables contain records (rows) with data. for example,

- SQL Statements

 

           Some of The Most Important SQL Commands and we will try to use each of statement in other topics.

• SELECT - extracts data from a database
• UPDATE - updates data in a database
• DELETE - deletes data from a database
• INSERT INTO - inserts new data into a database
• CREATE DATABASE - creates a new database
• ALTER DATABASE - modifies a database
• CREATE TABLE - creates a new table
• ALTER TABLE - modifies a table
• DROP TABLE - deletes a table
• CREATE INDEX - creates an index (search key)
• DROP INDEX - deletes an index
  
  
  

           Semicolon is the standard way to separate each SQL statement in database systems that allow more than one SQL statement to be executed in the same call to the server. In this tutorial use semicolon at the end of each SQL statement.

Reference : w3school Tutorial website