Today we are going to build a Web Service that will return a stock price given a particular stock symbol. This is a classic example of where Web Services are of great use.
You may be building an application that needs the data and could very easily just pull the data directly from your data source. Building a Web Service for it, however, allows you to give other applications easy access the same data in the future. It also separates the data extraction from the data source from the application itself. Say you were storing the data in a MySQL database but later decided to move it to a SQLite database... in this scenario your application wouldn't know the difference. Its calls to the Web Service remain unchanged.
To provide a stock quote service you will have to have the stock prices and symbols stored in some fashion or another. This tutorial is not going to concentrate on the storage mechanism or how to obtain the prices. I will simply provide you will a table schema and some sample data to work with.
CREATE TABLE `stockprices` ( `stock_id` INT UNSIGNED NOT NULL AUTO_INCREMENT , `stock_symbol` CHAR( 3 ) NOT NULL , `stock_price` DECIMAL(8,2) NOT NULL , PRIMARY KEY ( `stock_id` ) ); INSERT INTO `stockprices` VALUES (1, 'ABC', '75.00'); INSERT INTO `stockprices` VALUES (2, 'DEF', '45.00'); INSERT INTO `stockprices` VALUES (3, 'GHI', '12.00'); INSERT INTO `stockprices` VALUES (4, 'JKL', '34.00');