Website Development & Management PHP Odds & Ends Instructor: John Seydel, Ph.D. CIT Fall

Student Objectives Upon completion of this class meeting, you should be able to: Summarize the steps involved in using PHP to accomplish basic database queries Use PHP to display database contents to a web page Create an onLoad event handler for a web page

Using PHP to Interface with MySQL Always starts with the creation of a connection Requires opening a database Generally involves generating a recordset (aka, result set) Processing the recordset typically involves some sort of looping construct One repetition per record Must be controlled by some sort of counter: foreach(), while(), and for() Makes use of several important functions...

PHP Functions for Basic Queries Create a connection: mysql_connect() Arguments (string): server, userID, password Returns a string (connection information) Open a database: mysql_select_db() Arguments (string): database to be used, connection Returns a boolean value Create a recordset: mysql_query() Arguments (string): SQL query, connection Returns a recordset (an array of data) Process a recordset: mysql_num_rows()  Argument (array): recordset  Returns an integer (number of records) mysql_fetch_array()  Arguments (string): recordset  Returns a row from the recordset

Let’s Complete the First Database Exercise Where we left off: Initial values assigned Connection created Database opened Recordset created Note: three line equivalent (poor coding) What’s left: Process the records (a row at a time)  Get data for each row in the database table  Assign those data to variables  Add to the output block Incorporate output block into the HTML section

A Bit More on QueriesQueries Not just getting information from a database Also involves putting information into a database Creating databases Creating tables Adding records to tables Modifying (updating) existing records Require the use of SQL (structured query language), a universal database language Reference material: so far, mostly the class notes

Summary: What We’ve Seen Recently New PHP functions mysql_connect() mysql_select_db() mysql_query() mysql_num_rows() mysql_fetch_array() A little SQL Used directly with MySQL Incorporated into PHP script The for() construct How to use PHP to connect to MySQL, open a database, create a recordset, and process that recordset How/where MySQL files are storedstored

The FKAuto Database Files For use on your own computer: Download these Available in the Documents directory (not public_html) of the cit3353 account on SuSE1  Recall the password?  All three files for the UsedCars database are in a directory named fkauto For use on SuSE1: don’t worry about where they are, as they are available to your scripts However, the “owner” is user cit3353 Thus use the appropriate values for user and password

Some Other Things: FKAuto Calculator Page (calc.php) JavaScript: used within the onLoad event handler for the element Note the arrays Use of the range() function Alternatively, but more work: array() foreach() construct

Appendix

How MySQL Stores the Data Each table (i.e., relation) involves three files: TableName.frm TableName.MYD (where the actual data are) TableName.MYI The files for all the tables belonging to a given database are stored in a directory with the same name as the database All database directories are stored in the data directory within c:\mysql

Working with MySQL Get started mysql -u jojobeans –p USE testDB; SHOW TABLES; Using tables CREATE TABLE tblTest (testID int, testNote text); EXPLAIN tblTest; SELECT * FROM tblTest; INSERT INTO tblTest VALUES (123,’First entry’); INSERT INTO tblTest VALUES (456,’Second entry’); SELECT * FROM tblTest; QUIT;