# SQL Overview
# What is a Relational Database?
Uses a structure that allows us to identify and access data in relation to another piece of data in the database. Often organized into tables.
# What is a Relational Database Management System (RDBMS)?
A program that allows you to create, update, and administer a relational database. Most relational database management systems use the SQL language to access the database.
# What is SQL?
SQL (Structured Query Language) is a programming language used to communicate with data stored in a relational database management system.
Many RDBMSs use SQL (and variations of SQL) to access the data in tables
Since 1974 - became a standard of the American National Standards Institute (ANSI) in 1986, and of the International Organization for Standardization (ISO) in 1987
Note: Most of the SQL database programs also have their own proprietary extensions in addition to the SQL standard!
# Popular Relational Database Management Systems
MySQL is the most popular open source SQL database. typically used for web application development
easy to use, inexpensive, reliable (has been around since 1995), and has a large community of developer
disadvantages: poor performance when scaling, does not include some advanced features
open source SQL database that is not controlled by any corporation. It is typically used for web application development.
- shares many of the same advantages of MySQL. It is easy to use, inexpensive, reliable and has a large community of developers. It also provides some additional features such as foreign key support without requiring complex configuration.
- disadvantage:it can be slower in performance than other databases such as MySQL. It is also slightly less popular than MySQL.
read this (opens new window) article.
Video: what is PostreSQL (opens new window)
Oracle Corporation owns Oracle Database, and the code is not open sourced.
for large applications, particularly in the banking industry.
disadvantage: not free to use like its open source competitors and can be quite expensive.
Microsoft
Large enterprise applications mostly use SQL Server.
Microsoft offers a free entry-level version called Express but can become very expensive as you scale your application.
popular open source SQL database. It can store an entire database in a single file. One of the most significant advantages this provides is that all of the data can be stored locally without having to connect your database to a server.
SQLite is a popular choice for databases in cellphones, PDAs, MP3 players, set-top boxes, and other electronic gadgets.
read this (opens new window) article.