Databases Archive

Motivations of why to Learn Databases

Before we define or explain what a database or even argue whether it is important for software development, let us ask the simple question: Can we create a software application without the use of a database system. To make it easier for you to answer such question, we take the simple example ...Read More

How to Convert ER Diagram to Relational Database

The ER Model is intended as a description of real-world entities. Although it is constructed in such a way as to allow easy translation to the relational schema model, this is not an entirely trivial process. The ER diagram represents the conceptual level of database design meanwhile the relational schema is the ...Read More

List of Recommended Websites to Learn Databases

Here is a set of websites that we recommend for people starting to learn databases: SQL Zoo :  http://sqlzoo.net/wiki/Main_Page SQLZoo includes tutorials and reference to support people learning SQL.   The website is available in English, German, and French. The site includes : Interactive access to several SQL engines. Sample databases, Practical exercise ...Read More

BaseX : Tutorial for using an XML Native Database Management System

XML is defined as a textual structured format for storing, representing and communicating data. The XML format is based on opening and closing tags for enclosing data content. As opposed to traditional databases, XML documents are portable and can be opened on any platform using any programming language. BaseX is a native ...Read More

Making Connection to Oracle Database System with Java

Oracle Database Creation 1 Open your Apex for Oracle: Click on Start -> All Programs -> Oracle database 11g Express Edition -> Go to Database Home Page 2 Visit the SQL Command : SQL -> SQL Command 3 Execute the following SQL to create a table called friends. create table friends( fname ...Read More

Oracle : Type/Object Creation, Inheritance and Method Implementation with Examples

In this tutorial, we will try to go through a problem for modelling a system for storing polygon objects which have their own methods for computing the area or perimeter. The objects that we should have are : Point ( x , y ) Side ( Point, Point ) Polygon ( Sides) ...Read More

Tutorial for how to Get started to learn Oracle

Oracle is an object-relational database management system. It allows users to create, maintain, modify, and even erase any and all data and objects within an existing database. 1 You need to download the Oracle XE (Express Edition) to quickly get started with it. 2 Once you have downloaded the XE version, unzip ...Read More

SQL tutorial for using Having with Examples

The HAVING statment  is added to SQL because the WHERE keyword could not be used with aggregate functions ( such as count, max …) The syntax for using HAVING is as below:   SELECT column_name, aggregate_function(column_name) FROM table_name WHERE column_name operator value GROUP BY column_name HAVING aggregate_function(column_name) operator value; Example for Database ...Read More

Advanced SQL SELECT Tutorial using Aggegrate Functions by Examples

The important SQL command is SELECT statement. The SQL SELECT statement is used to query or retrieve data from a table in the database. A query may retrieve information from specified columns or from all of the columns in the table: Syntax of SQL SELECT Statement: SELECT column_list FROM table-name [WHERE Clause] ...Read More

SQL Simple Exercises using MySQL and phpMyAdmin

1 Open phpMyAdmin. Click : Databases to create a new database with the name : ecommerce, Click Create 2 Click on the database ecommerce on the left side. 3 Download the database ecommerce.sql file. 4 Click Import and choose Browse to upload the following SQL file. Click GO once done. 5 Click ...Read More