Integrating Databases into the Web with PHP/MySQL CS 4000

Getting Started PHP and MySQL are a powerful team for developing fully interactive database-driven Web sites. Starting with a Web server (like Apache), you simply download and install MySQL and then download and install and configure PHP on the server (in that order).

Intro to MySQL Once you have MySQL and PHP installed and configured for your server, you need to create the database to hold the information for your application. Go into the mysql folder on your server, then into the bin folder and type mysql. This begins the MySQL command interpreter (your command line prompt will change to “mysql>”).

Creating a database You can see what databases currently exist on the server with the command: –SHOW DATABASES; To create a database, use the command “CREATE DATABASE” followed by the name of the database you want to create (simple, huh?). For example, to create a database to hold information on employees, you could type: –CREATE DATABASE employdb;

Selecting a Database for Use You must then select the database so that you can enter data into it. To do this, use the USE command: –USE employdb; Now you have created a database and selected it for use.

Tables for Data The next step is putting in some information to use in your queries for your Web page. This is done in the form of tables. You can see the tables associated with your database by using the SHOW command: –SHOW TABLES; But, since you just created your database, there are no tables yet associated with your database.

Creating Tables of Data To create one or more tables for your database, you should first consider carefully –what kind of information you want to include in the table, as well as –the field type and length of each data element.

Creating Tables For example, to create a table named “emp_position” in the above database, with fields for employee number (9 characters), job title (20 characters), job code (an integer), and hourly pay rate (a decimal value), we could do the following: –CREATE TABLE emp_position (emp_num VARCHAR(9), jbtitle VARCHAR(20), job_code INT, hrly_rate FLOAT);

Adding Data to Tables To verify that your table was successfully created, type DESCRIBE emp_position;. Now you are ready to import data into your database. If you are starting a table from scratch, create a simple text file with tabs separating the values on each line, as below: Janitorial Staff ICAPP Professor Web Designer

Adding Data cont. With each column corresponding to the order in our table, we would have an employee # who is a member of the Janitorial Staff, job code 1142, whose hourly pay rate is $11.50, and so on. Save this text file as EmployeePositionList.txt, for example.

Loading Data into a Table Once you have created a “tab-delimited” text file (tabs separate the fields on a row), use the LOAD command to load the data into the database: –LOAD DATA LOCAL INFILE “EmployeePositionList.txt” INTO TABLE emp_position; All of the data in the text file will be put into the table. If you are starting with a spreadsheet or other file of information that you need to import into the database, format it as a text document with tab delimiters and follow the procedure above.

Inserting Rows One at a Time You may also insert rows one-by-one, using the INSERT command: –INSERT INTO emp_position VALUES (‘ ’, ‘ICAPP Student’, ‘3131’, ‘100.00’); While you might not want to enter many values this way at the command prompt, a good use for this is to insert values from a form into a Web database using PHP, as is covered in the PHP section.

Retrieving Information: SELECT To retrieve information from a database table, the SELECT statement is used. A general form of the statement is: –SELECT fields_to_show FROM name_of_table WHERE condition_needed ORDER BY field_name_to_sort_by;

SELECTing rows & columns So, to show all fields from the emp_position table for employees whose pay rate is over $10.00 per hour, sorted by pay rate, we would use: –SELECT * FROM emp_position WHERE hrly_rate>10.00 ORDER BY hrly_rate; That should be just enough mySQL to give us what we need to do the database interface in PHP.

Next Time We’ll talk about PHP