PHP Programming

1
PHP Programming
2
Topics

• Background and History of PHP
• Installation
• Comments in PHP
• Variables
• Conditions
• Loops
• Functions
• File Handling
• Database Handling (MySQL, MSSQL, ODBC)

3
Background

• Personal Home Page C kind of scripts written in
  Perl language, by Rasmus Lerdorf in 1995.
• He called the language as PHP/FI Personal Home
  Page / Forms Interpreter.
• 1997 Version 2.0 was released
• Then came 3.0, 4.0. They were called PHP simply
• Recent version is PHP 5.2.3

4
Installation

• Apache server need to be installed first
• The config file for apache server will be present
  in the conf folder under the apache installed
  directory
• Set the DocumentRoot to the path where the PHP
  files will be stored
• Install PHP. Point apache conf directory when it
  asks so and select the appropriate web server.
• Move the PHP.ini file to C\WNDOWS directory

5
PHP Comments

• All php files are saved with extension .php
• The can be written in notepad or any text editor
• Single line comment
• // this is single line comment
• Multi line comment
• /.
• This is a multi line comment /

6
Sample PHP

• lthtmlgt
• ltbodygt
• lt?php echo hello ?gt
• lt/htmlgt
• The above program will display hello in the
  browser

7
Variables

• Variables start with a symbol
• Variables can contain _ or numbers or alphabets
• should be followed by _ or alphabet and not by
  a number
• PHP is loosely typed language. There is no strict
  data typing
• Variable can be assigned with any values

8
Conditions

• If else
• if(condn) .
• elseif(condn) .
• else .
• Switch case
• switch(var)
• case c1 statementsbreak
• .
• .
• Default statements break

9
Loops

• For
• for(intialisationconditionincrement/decrement)
• statements
• While
• while(condn) .
• Do While
• do . while(condn)

10
Functions and Parameters

• PHP functions need to be defined with key word
  function
• It can have zero or more values (parameters)
• Functions may or may not return values
• If a function need to return value, the last
  statement of the function should be return
• return value

11
Functions

• Parameter less function
• lt?php
• function sayHi()
• echo hi
• ?gt
• This can be called as lt?php sayHi() ?gt in the
  program

12
Functions

• Parameterized function
• lt?php
• function greet(name)
• echo Hello . name
• ?gt
• This can be called lt?php greet(Ram)?gt
• This gives an output Hello Ram

13
Functions

• Function returning value
• lt?php
• function add(a,b)
• return (a b)
• ?gt
• When called like lt?php echo add(1,2)?gt we
  will get an output 3 in the browser.

14
File Handling

• This involves 5 tasks
• Opening a file
• Reading data from a file
• Displaying the read data
• Writing contents to another file
• Closing a file

15
Opening a file

• fp fopen(filename,mode)
• Eg fp fopen(c\abc.txt,r)
• This opens a file abc.txt in read only mode
• Available modes
• r read only
• w write only
• w - read write
• A append adding to the end

16
Reading a file

• Several methods are available
• fread(filepointer,no of bytes to read)
• fgetc(filepointer) Reads character by character
• fgets(filepointer) Reads line by line
• The read content can be stored in a variable
• data fread(fp,10) this reads 10 characters
  from file pointed by file pointer fp and stores
  in data
• If we want to read characters till end, we need
  to use a loop with condition checking for End of
  File

17
Writing to file

• We can use echo data, to print the contents read
  from the file to browser
• Or we can open another file in write mode and put
  the contents to that file using either of these
  methods
• fwrite(filepoiner,data)
• fputc(filepointer,char) - writes character by
  character
• fputs(filepointer,line) - writes line by line
• Eg - fwrite(fpw,data)

18
Closing a file

• feof(fp) Checks for end of file.
• Returns 1 if EOF is reached. Otherwise returns 0
• To close a file use fclose(filepointer) method
• Eg. fclose(fp)
• This closes the file pointed by fp.

19
Database Handling

• PHP can connect to
• MySQL
• MSSQL
• Access and other databases like oracle, postgre
  sql etc
• There are separate methods available for
  connecting to the databases

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MySQL and MSSQL Connection

• mysql_connect(dbserver,userid,password)
• mssql_connect(dbserver,userid,password)
• These methods are used for connecting to MySQL
  and MSSQL server using a userid and password
• con mysql_connect(localhost,root,root)
• This gets a connection to the local mysql server
  using the credentials root and root
• If server cannot be connected, it will throw an
  error stating the problem
• Note Mysql and MSSQL can be accessed in
  identical way except for the preceeding mysql or
  mssql. So will use mysql henceforth.

21
MySQL Select DB

• mysql_select_db(connection,dbname)
• mysql_select_db(con,test)
• This will select the db test under the server
  localhost
• If unable to select the database, an error will
  be thrown

22
MySQL Execute Query

• mysql_query(connection,sql statement)
• This will execute the sql statement on the
  database and store the result in a variable
• Eg
• rs mysql_query(con,select stmt)
• The rows of select statement will be stored in
  rs
• row mysql_fetch_array(rs)
• This will fetch a row and store in row
• Values can be accessed like - rowID
  returns value of column ID in the fetched row.

23
MySQL and MSSQL Close

• To close a db connection we have close method
• mysql_close(connection)
• mssql_close(connection)
• Example
• mysql_close(con)
• mssql_close(con)

24
ODBC Data handling

• Connect to a data source
• odbc_connect(dsn,uname,pwd)
• DSN Data Source Name
• Go to Control Panel -gt Administrative Tools -gt
  Datasources (ODBC)
• Click on ODBC and select System DSN tab.
• Click Add and choose Access Database (mdb) and
  click Finish
• In the dialog that appears, give DSN Name and
  Description

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ODBC Data handling Contd..

• Click on Select under Database section
• Choose a mdb (access database file) and give OK
• connodbc_connect('nwind','','')
• Here nwind is the DSN that we have created in our
  system to access a database
• We have not given any user name or password
  during DSN creation
• So those fields are left empty.

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Selecting rows from a table

• rs odbc_exec(conn,sql)
• conn connection string
• sql SQL query to select rows from table
• rs is the result set of the query execution
• odbc_fetch_row(rs)
• This command fetches row by row from the result
  set
• cid odbc_result(rs,"CustomerID")
• This command fetches value for the column
  CustomerID from the current row and stores it in
  the variable cid.

27
Closing Connection

• odbc_close(connection)
• This function closes the connection obtained and
  releases the same to the connection pool
• odbc_close(conn)
• The connection defined by conn is released and
  no query can be executed using this connection
  variable hence forth.