EE 495M - Lecture 3. Overview

Transcription

1 EE 495M - Lecture 3 mysql and PHP Mustafa Kamasak September 10, 2003 Overview Database Tier (MySQL) SQL Logic Tier (PHP) Web Server Presentation Tier (Browsers) MySQL SQL PHP MySQL & PHP interface

2 MySQL - Basics To start mysql type mysql -u username -p and enter your password when prompted. A commandline interface will be started. $ mysql -u ims -p Starting MySQL as user IMS Enter password: Welcome to the MySQL monitor. Commands end with ; or \\g. Your MySQL connection id is to server version: Type help; or \\h for help. Type \\c to clear the buffer. mysql> show databases will show the list of the databases in the server. mysql> show databases; Database test1 test rows in set (0.00 sec) mysql> MySQL - Basics To create a new database use create database dbname mysql> CREATE DATABASE ee495m; Query OK, 1 row affected (0.00 sec) mysql> show databases; Database ee495m test1 test rows in set (0.00 sec) To select a database type use dbname To see the tables inside this database use show tables mysql> USE ee495m Database changed mysql> SHOW TABLES; Empty set (0.00 sec) mysql>

3 MySQL - Tables To create a new table CREATE TABLE table_name (column1_name type [modifiers],...) mysql> CREATE TABLE students(student_id INT(9) NOT NULL PRIMARY KEY, -> FIRST_NAME VARCHAR(30), -> LAST_NAME VARCHAR(30), -> PROJECT VARCHAR(10) NOT NULL); Query OK, 0 rows affected (0.00 sec) mysql> Column types BIGINT BLOB CHAR CHARACTER CHARACTER VARYING DATE DATETIME DEC DECIMAL DOUBLE DOUBLE PRECISION ENUM FLOAT INT INTEGER LONGBLOB LONGTEXT MEDIUMBLOB MEDIUMINT MEDIUMTEXT NCHAR NATIONAL CHAR NATIONAL CHARACTER NATIONAL VARCHAR NUMERIC REAL SET SMALLINT TEXT TIME TIMESTAMP TINYBLOB TINYINT TINYTEXT VARCHAR YEAR MySQL - Basic Column Types The M is the display width and D is the number of digits after decimal point. INT[(M)] [UNSIGNED] A normal-size integer. The signed range is to The unsigned range is 0 to CHAR(M) A fixed-length string that is always right-padded with spaces to the specified length when stored. The range of M is 0 to 255 characters. VARCHAR(M) Values in VARCHAR columns are variable-length strings. You can declare a VARCHAR column to be any length between 1 and 255, just as for CHAR columns. Trailing spaces are removed when values are stored. FLOAT[(M,D)] [UNSIGNED] A small (single-precision) floating-point number. DOUBLE[(M,D)] [UNSIGNED] A normal-size (double-precision) floating-point number. DATE A date. The supported range is to TIME A time. The range is -838:59:59 to 838:59:59.

4 To see the fields of a table DESCRIBE table_name MySQL - Table Modifications mysql> describe students; Field Type Null Key Default Extra STUDENT_ID int(9) PRI 0 FIRST_NAME varchar(30) YES NULL LAST_NAME varchar(30) YES NULL PROJECT varchar(10) 4 rows in set (0.00 sec) If a table structure needs to be modified ALTER TABLE table_name action_list mysql> ALTER TABLE students ADD COLUMN (PHONE CHAR(13)); Query OK, 0 rows affected (0.01 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> describe students; Field Type Null Key Default Extra STUDENT_ID int(9) PRI 0 FIRST_NAME varchar(30) YES NULL LAST_NAME varchar(30) YES NULL PROJECT varchar(10) PHONE varchar(13) YES NULL 5 rows in set (0.00 sec) Modify column type MySQL - Table Modifications mysql> ALTER TABLE students MODIFY PROJECT varchar(15); Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> describe students; Field Type Null Key Default Extra STUDENT_ID int(9) PRI 0 FIRST_NAME varchar(30) YES NULL LAST_NAME varchar(30) YES NULL PROJECT varchar(15) YES NULL PHONE varchar(13) YES NULL 5 rows in set (0.00 sec) Delete a column mysql> ALTER TABLE students DROP PHONE; Query OK, 0 rows affected (0.01 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> describe students; Field Type Null Key Default Extra STUDENT_ID int(9) PRI 0 FIRST_NAME varchar(30) YES NULL LAST_NAME varchar(30) YES NULL PROJECT varchar(15) YES NULL 4 rows in set (0.00 sec)

5 MySQL - Deleting Change Table Name mysql> ALTER TABLE students RENAME TO alumni; Delete Column mysql> ALTER TABLE students DROP COLUMN column_name; Delete Table mysql> DROP TABLE table_name; Delete Database mysql> DROP DATABASE db_name; SQL - Structured Query Language To insert data into a table INSERT INTO table_name (columnk_name,...) VALUES (columnk_value,...) mysql> INSERT INTO students (STUDENT_ID,PROJECT) VALUES ( , eact ); Query OK, 1 row affected (0.00 sec) To see the contents of a table SELECT column_name(s) FROM table_name WHERE conditions mysql> SELECT * FROM students; STUDENT_ID FIRST_NAME LAST_NAME PROJECT NULL NULL eact row in set (0.00 sec)

6 SQL - Structured Query Language To update a record mysql> UPDATE table_name SET column_name=column_value WHERE conditions mysql> UPDATE students SET FIRST_NAME= John WHERE STUDENT_ID= ; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> SELECT * FROM students; STUDENT_ID FIRST_NAME LAST_NAME PROJECT John NULL eact rows in set (0.00 sec) To delete a record mysql>delete FROM table_name WHERE conditions mysql> delete from students; Query OK, 0 rows affected (0.01 sec) mysql> select * from students; Empty set (0.00 sec) SQL - Examples Initial Table mysql> SELECT * FROM students; STUDENT_ID FIRST_NAME LAST_NAME PROJECT John NULL EAct John Smith EPrint John1 Smith EAct Jr. John Smith EAct John Smith EPrint Ganesh Anand EAct Karl Hiedermann EAct Peter Harper EAct Arman Gucci EPrint rows in set (0.00 sec) Find the first names of EPrint team members mysql> SELECT FIRST_NAME FROM students WHERE PROJECT= EPrint ; FIRST_NAME John John Arman rows in set (0.01 sec)

7 SQL - Examples Ordering entries mysql> SELECT * FROM students ORDER BY STUDENT_ID; STUDENT_ID FIRST_NAME LAST_NAME PROJECT John NULL EAct John Smith EPrint John1 Smith EAct Jr. John Smith EAct John Smith EPrint Peter Harper EAct Karl Hiedermann EAct Ganesh Anand EAct Arman Gucci EPrint rows in set (0.00 sec) Delete all students that have Smith as their last name. mysql> DELETE FROM students WHERE LAST_NAME= Smith ; Query OK, 4 rows affected (0.00 sec) mysql> SELECT * FROM students; STUDENT_ID FIRST_NAME LAST_NAME PROJECT John NULL EAct Ganesh Anand EAct Karl Hiedermann EAct Peter Harper EAct Arman Gucci EPrint rows in set (0.00 sec) SQL - Examples A second table in ee495m database mysql> SELECT * FROM equipment; STUDENT_ID EQ Laptop pocketpc Laptop Laptop Network Card rows in set (0.00 sec) Find the first and last names of the students who got Laptop mysql> SELECT FIRST_NAME, LAST_NAME FROM students,equipment -> WHERE students.student_id = equipment.student_id -> AND equipment.eq = Laptop ; FIRST_NAME LAST_NAME Peter Harper Karl Hiedermann Ganesh Anand rows in set (0.01 sec)

8 SQL - Examples Find the equipment that is given to Peter Harper. mysql> SELECT EQ FROM students,equipment -> WHERE students.student_id = equipment.student_id -> AND students.first_name= Peter -> AND students.last_name= Harper ; EQ Laptop pocketpc Network Card rows in set (0.00 sec) PHP - Advantages PHP can be embedded into HTML files It is open source and has many open source libraries. Easy access to database servers

9 PHP - Introduction Simple hello.php <html> <head> <title>php Test</title> </head> <body> <?php echo "<p>hello World</p>";?> </body> </html> To begin script following tags can be used <script language="php"> PHP code </script> <?php PHP code?> <? PHP code?> Each PHP statement is terminated by a semicolon While spaces in the code is not important When a PHP script is executed the output of the script is replaced into the starting and ending tags PHP - Comments and Variables To comment PHP scripts following can be used // One line comment # Another one line comment /* Multi line comment */ PHP variables begin with $ sign followed by the variable name. Variables don t need to be declared. They have no type until they are assigned a value. $var = 15; // integer $var = 15.0; // float $var = "EE495M"; //string PHP four scaler types, boolean, float, integer and string - two compound types, array and object.

10 PHP - Arrays PHP provides array() to create arrays, for example $numbers=array(3,5,7,2); $la_liga_clubs=array("real Sociedad","Real Madrid","Valencia","Deportiva"); By default index for the first element starts from 0. Arrays can be created with different indexing. $numbers=array(1=>"one","two","three"); # Starts from index 1 $primes=array(2=>"two",3=>"three",5=>"five"); Strings can be used as indexes (keys). These arrays are called associative arrays. Multidimensional arrays can be created using nested array(). $points = array( array("x"=>0.77,"y"=>0.54,"z"=>0.2), array("x"=>0.37,"y"=>0.22,"z"=>0.32)); $points[1]["y"] = 0.22 PHP - Array Functions count(array) returns the number of elements in the array. min(array) and max(array) returns the minimum and maximum values in the array. in_array(element,array) returns true if the array contains element. array_reverse(array) reverses the order of array but preserves the associations. sort(array) and rsort(array) sorts the arrays in ascending and descending orders, respectively. $my_array = array(10,5,7,105,2); echo count($my_array); // 5 echo max($my_array); // 105 echo min($my_array); // 2 for ($i=0;$i<110;$i++) { if (in_array($i,$my_array)) { echo $i; // $new_array = reverse_array($my_array); echo $new_array[0]; // 2 $new_array = sort($my_array); echo $new_array[1]; // 5 $new_array = rsort($my_array); echo $new_array[1]; // 10

11 PHP - Expressions and Operators PHP Expressions $b = $a = 5; /* assign the value five into the variable $a and $b */ $c = $a++; /* post-increment, assign original value of $a */ $e = $d = ++$b; /* pre-increment, assign the incremented value of $b */ $f = double($d++); /* assign twice the value of $d before the increment */ $g = double(++$e); /* assign twice the value of $e after the increment */ $h = $g += 10; /* first, $g is incremented by 10 and the value of the assignment is then assigned into $h*/ PHP Operators Operator Description. string concatenation or, and, xor bitwise logical operators, &, ^ bitwise logical operators, && logical operators +,-,*,/,++,-- arithmetic operators <<,>> shifting operators ==,!=,!==,=== conditional operators Note === is a PHP specific operator. It returns true is both the values and types are equal, for example 5 === 5 // true 5.0 === 5 // false 5.0 == 5 // true PHP - Conditions and Branches if..else statement if ($var < 5) { echo "Variable is smaller than 5."; else { echo "Variable is bigger than 5 or equal to 5."; switch statement switch ($var) { case 1: echo "Variable is 1"; break; case 2: echo "Variable is 1"; break; default: echo "Variable is not 1 or 2";

12 PHP - Loops while and do..while $counter = 1; while ($counter<10) { echo "Counter is $counter"; $counter ++; do { echo "Counter is $counter"; $counter --; while ($counter>0); for for ($level=1,$lives=5;$level<15,$lives>0;$level++,$lives--) { // Do some stuff foreach $lengths = array(0,50,102,123); foreach ($lengths as $cm) { echo "$cm cm is $cm/2.45 inch."; PHP - Printing and Formatting Other than echo, integer printf(string format,arguments) and string sprintf(string format,arguments) can be used to print out a string or variable and to format a sting. The functions are almost same as C/C++. $counter=1; $days=array("mon","tue","wed","thu","fri","sat","sun"); while ($counter<8) { $today = sprintf("today is %s",$days[$counter]); printf("%d => %s\n",$counter,$today);

13 Functions are defined as follows PHP - User Defined Functions function square($num) { $sq = $num * $num; echo "Square of $num is $sq"; The argument and return types are not declared when the function is defined. function divide($a,$b) { return($a*$b); $c = divide(3,2); // c will be 1.5 By default arguments are passed by values. Arguments can be passed by reference as follows function double($a) { $a *= 2; function double1(&$a) { $a *=2; $a = 3; double($a); echo "$a"; // 3 double1($a); echo "$a"; // 6 Default arguments can be passed function divide($a,$b=2) { return($a/$b); $b=divide(5); // b will be 2.5 PHP - File IO To open a file use: fopen(string filename,string mode,int use_include_path); This function returns a handle to the file, which will used to access the file to read, write etc. If the file cannot be opened, it will return 0. Available modes are: Mode Access Type r Access the file for reading only. r+ Access the file for reading and writing. w Access the file for writing only. If the file exists, erase all contents. w+ Access the file for both reading and writing. If the file exists, erase all contents. a Open the file for writing only. If the file exists, access will start from the end of the file. a+ Open the file for reading and writing. If the file exists, access will start from the end of the file. If use_include_path is true and the file cannot be found in the specified directory, an attempt will be made to find the file in the directories specified by the PHP s include path.

14 PHP - File IO To read from the file: fgets(int file_handle,int length); the file_handle is the number returned by fopen function and the length is the number of bytes requested from the file. If length is skipped it will return a line from the file until EOF is reached. It will return the string read from the file or false if an error occurs. To write to the file: fputs(int file_handle,string str,int length); Returns the number of bytes written or -1 if an error occurs. To close the file: fclose(int file_handle); Other PHP functions for file IO. feof fflush fgetc file_exists filesize fileperms fread fscanf fseek ftell fstat fwrite PHP - File IO Example Simple web counter <? $visitors = 0; $fp = fopen( counter.txt, r ); if (!$fp) { $visitors = 1; $fp = fopen( counter.txt, w ); if (!$fp) { echo "Cannot open counter.txt"; exit; fputs($fp,$visitors); fclose($fp); else { $visitors = fgets($fp); $visitors ++; echo "This page have been visited $visitors time."; fclose($fp);?> $fp = fopen( counter.txt, w ); if (!$fp) { echo "Cannot open counter.txt"; exit; fputs($fp,$visitors); fclose($fp);

15 MySQL & PHP Basic PHP connection to a MySQL server consists of five steps: Connect the database resource mysql_connect(string hostname,string username, string password); The function returns a connection resource handle on success that will be used to access database, returns false on failure. Selecting a database int mysql_select_db(string database,resource connection); Executing SQL query resource mysql_query(string query,resource connection); Returns a result handle that will be used to fetch the result. Fetch the results of the query array mysql_fetch_row(resource result)) Returns an array of one row from the query result. It returns false when there is no more rows available. Close the connection int mysql_close(resource connection Index.php <HTML> <? if (!($connection = mysql_connect("localhost","foo","hardtofind"))) { die("cannot connect to database"); if (!mysql_select_db("ee495m",$connection)) { die("error ". mysql_errorno().": ". mysql_error()); $query = "SELECT FIRST_NAME,LAST_NAME,EQ FROM students,equipment WHERE students.student_id=equipment.student_id ORDER BY FIRST_NAME"; if (!($result = mysql_query($query,$connection))) { die("cannot connect to database"); print("<table BORDER>\n"); printf("<tr><td>name</td><td>equipment</td></tr>\n"); while ($row = mysql_fetch_array($result)) { printf ("<TR><TD> %s %s</td><td> %s</td></tr>\n", $row[0], $row[1],$row[2]); printf("</table>\n"); if (!mysql_close($connection)) { die("error ". mysql_errorno().": ". mysql_error());?> </HTML>

16 MySQL & PHP - Frequently used functions array mysql_fetch_array(resource,int) This function is extended version of mysql_fetch_row() It can fetch the results of a query as an associative array. Second parameter controls whether associative access (MYSQL_ASSOC) or numeric access (MYSQL_NUM) or both (MYSQL_BOTH) on the returned object. object mysql_fetch_object(resource,int) Instead of fetching an array this function fetches the result of a query as an object that can be accessed by column names. $object = mysql_fetch_object($result,mysql_both); echo $object->first_name; echo $object->eq; int mysql_free_result(resource) Normally memory buffered for the result of a query is released when the script ends. But if multiple queries need to be done in a script the resources used for the results must be freed. int mysql_num_rows(resource) This function returns the number of rows associated with the result of a query. A complete list of mysql functions can be found at Homework - Due September 17, 2003 Assume that, mysql server is installed on your localhost and you can access it with the following login and password: login: ee495 password: doesntmatter There is a database in this server called worldcup2002. It has three tables: teams games scorers

17 Homework Posted at: mobility/homeworks/hw2.html The description of these tables are as follows: mysql> describe teams; Field Type Null Key Default Extra team_id int(3) PRI NULL auto_increment name varchar(50) YES NULL rows in set (0.00 sec) mysql> describe games; Field Type Null Key Default Extra game_id int(3) PRI NULL auto_increment team1 int(3) YES NULL team2 int(3) YES NULL score varchar(10) YES NULL rows in set (0.00 sec) mysql> describe scorer; Field Type Null Key Default Extra name varchar(30) YES NULL team_id int(3) YES NULL game_id int(3) YES NULL goals int(3) YES NULL rows in set (0.00 sec) Homework The initial contents of these tables are given on the web site. Write hw1.php that will connect the mysql server and find all games of Turkey and list them (games+scores) with the scorers in those games. Format the output into a HTML table, eg. Team1 Team 2 Score Goals Brazil Turkey 2-1 Hasan Sas, Ronaldo, Rivaldo Write hw2.php that will connect the mysql server and find all games that Ronaldo OR Rivaldo scored and list them. Format the output into a HTML table. Scorer Team1 Team2 goals Ronaldo Brazil Turkey How to return: Use Winzip to compress all php files, name it Your Last Name.zip and it to mobility@ecn.purdue.edu. The subject of the should be: TEAM NAME HW 2.

18 References References [1] [2] [3] Managing and Using MySQL, G. Reese, R. Yarger and T. King, O Reilly. [4] Web and Database Applications with PHP and MySQL, H. Williams and D. Lane, O Reilly.