getting started with php and oracle

7/30/2019 Getting Started with PHP and Oracle

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PHP for PL/SQL Developers

Lewis Cunningham

JP Morgan Chase

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What is PHP? PHP is a HTML pre-processor

PHP allows you to generate HTML dynamically

PHP is a scripting language usable on the web, theserver and the desktop

PHP is embeddable in HTML

PHP is resolved on the server, not in the browser

PHP has a very easy, and probably familiar, syntax

PHP is extremely easy for PL/SQL Developers to add totheir toolbox

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Where did PHP come from? Created by a developer who wanted to make his job

easier

Was originally just a set of Perl scripts Called Personal Home Page tools

Version 2.0 was re-written in C

3.0 extended PHP with many new APIs

4.0 Added bad OOP syntax

5.0 Fixed 4.0

6.0 is on the way

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How does PHP work? PHP files reside where HTML files live

The web server is configured to serve certain

extensions as static HTML (ex. HTM) and otherextensions as PHP (ex. PHP)

HTML is served unchanged, PHP is sent to the PHPprocessor

The PHP processor can talk to databases, performcomplex logic and knows how to build HTML

PHP returns control to the web server which thenreturns an HTML page to the requesting browser

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Why PHP for PL/SQL Devs? Familiar data types, all the usual (sort of)

Procedural OR Object syntax

Block based Exception handling

NULLs

Arrays and Objects

Large built-in function list

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Using PHP To use PHP, you'll need to install some softwware

Fortunately, PHP runs on pretty much any OS

You'll need a web server Download Apache and PHP

Download Zend Server CE (I'm using this today)

If you are using a database, install the database first -

I've had much better luck that way

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Hello World

Note: While PHP supports using


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Todays quick demo Convert a static HTML form to PHP

Have it use an Oracle database

Display existing dataAdd new data

Show Oracles OCI syntax and PHPs PDO syntax

In general, if you are working with Oracle, you arebetter off with OCI

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User Comments HTML Form

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A not very useful, static HTML form


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User Comments HTML FormWhat does it do?

Not much.

Can enter first name, last name and some comments. Press Ok and it calls itself, returning as an empty form.

What would we like it to do?

Enter the same information but save it to a database.

Also, display existing comments below the form.

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User Comments HTML Form

11name_page.php


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Same Form, as PHP

12name_page.php


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Huh? I just changed the extension from HTML to PHP

My web server is configured to recognize the PHP

extension and send that request to the PHP processor PHP pre-processes HTML

If it finds PHP instructions, it executes them

This page has no PHP so the processor passes it

through unchanged

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The First Change PHP Freebie

14name_page1.php


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Remember, ends it

The echo procedure is sort of like HTP.PRN, it sendsthe text to the web page

$ says this is a variable

_SESSION is a global super variable

Items in [] are array elements, $_SESSION is anassociative array

PHP instructions end with a ;

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Starting some real code

16name_page2.php


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Line 1 : Start PHP code

Lines 3-5 : Initialize variables

Line 7 : See if the _POST supervariable has my formsitems

Lines 8-10 : Assign the values of the _POST array to myvariables

Line 12 : Display variables to web page Line 14 : End PHP code

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Changing the HTML

18name_page2.php


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Redisplay entered data Remember the echo function sends output to the web

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Now when we run, before OK

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After OK

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Reusing Code in PHP Include Insert code into another script, will give a

warning if the file can't be found

Require Insert code into a script, fail with an error ifthe file can't be loaded

Include_once, require_once Same as the above butchecks to see if the file has already been loaded and

will not load it a second time Files for Include and Require can be anywhere on the

file system

PHP_INI has an INCLUDE_PATH

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Best Practice Alert Included and required files

Do not put your include files in the document root ofyour web server

You will often put important information, like databasepasswords, in these files

If the files are viewable, someone may find them, even ifaccidentally

You can put these files anywhere, on any file system,that is accessible from a command line

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Connecting to the Database

24name_page3.php


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The connection

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Yellow is the actual OCI connection string (username, password and database)

The code circled in red just displays an error message if the connection failsHtmlentities makes sure the text is safe to display on the web page

connect.inc


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After the connection In this case, unless the connection fails, we don't see

any differences

View the generated HTML code and there is nodifference there either

The connection will end when the current page isfinished being generated

You can use persistent connections and connectionpooling (both discussed further, later)

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Now to see some dataAt this point we want to see any existing records so we

will include code to select and fetch

That means creating a table in the database and

adding a record

27user_comments.sql


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Selecting some data

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We are adding a select and fetch step at the bottom ofour web page

name_page4.php


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Selecting and Fetching

29oci_fetch.inc


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Selecting and Fetching Line 3 : This is the select statement. This line is like the

parse step in DBMS_SQL

Line 5 : Executes the select and checks for success

Line 17 : This is the exception code that executesshould the oci_execute fail

Lines 6 15 : This is where the code is generated

An HTML table is created The while loop gets the row data

The foreach loops through the columnar data

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Looping This while loop in this code is a very traditional while.

While something is true, continue.

The foreach is much like the PL/SQL cursor for loop orlooping through an Oracle associative array (which inthis case, $row IS an associative array)

PHP also offers

DO..WHILE traditional do loop which always executesat least once before checking the condition

FOR Traditional for loop, for (init, check value,increment) for ($var = 1, $var


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Selecting and Fetching Oci_fetch_array fetches an easy to use associative array

Oci_fetch_array can return an associative array, a numericarray or both

Alternatives to oci_fetch_array are

Oci_fetch_row like fetch array but with only a numeric index

Oci_fetch_all Return ALL rows into a user defined array

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What it looks like now

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A little cleanup Best Practice? Time to clean up the HTML a little

Moving all executable code to INCLUDE files

Personal standard CSS External so that designers own it

DB Code External include files so that DB guys own it

PHP Code Mostly external so that pure code changes

are separate from HTML changes

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Init.inc

35init.inc


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Inserting a record, HTML change

36name_page5.php


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Why would insert be at the top? Unless you use AJAX, HTML only does something

when the user requests it

In this case, the user requests a new page

The new page is this page, but with any changesPOSTed

This is, by default, the only way for HTML to see a

change Request PageMake changes Submit Page

Server Processes Returns a new page

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Inserting a record, include file

38oci_insert.inc


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Inserting a record Lines 2-6 : Code that was in the HTML file, now

moved to the include file

Lines 8-10 : oci_parse, the SQL INSERT statement

Lines 12-14 : bind the page variables to SQL variables

Line 16 : The insert is executed

Lines 17-18 : Exception handling if insert fails

Line 20 : Success message

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No what is it doing?

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Can we improve this?A general best practice for any web application is to

not embed your data logic in the application

The optimal approach is to make an API available andkeep specific knowledge of the database, in thedatabase

In this case, both our insert and our select can be

moved to a stored procedureWill tackle the insert first

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A User Comments Package, Spec

42user_comments_pkg.sql


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A User Comments Package, Body

43user_comments_pkg.sql


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A new oci_insert.inc

44oci_insert_proc.inc


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What changed? The only thing that changed is that the insert was

converted to a stored proc call

The variables are still bound

The execution is the same

Exception handling is the same

The display hasn't changed

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Bigger changes for the Select

46oci_select_proc.inc


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Step by Step

We now have 2 cursors

A ref cursor is a cursor inside a cursorWe get a cursor on the stored proc call and another on

the OUT parameter for the return record set

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We bind the ref parameter (:ref) to the new cursor($ref_cursor)


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Step by Step

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We execute $stmt which is the stored proc call

If that is successful, we execute the ref cursor


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Step by Step The remainder of the code is executed as normal

The row fetch is followed by the item fetch, using the$ref_cursor variable instead of the $stmt variable

We handle execptions for both executes

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Using PDO instead of OCI OCI is an oracle specific driver

You can't run OCI against MySQL, or other databases

PHP offers a native wrapper called PDOWith PDO, your code can be reused between

databases

PDO does not support REF Cursors or some other

Oracle specific constructs Oracle recommends using the OCI package

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References and additional info PHP.net The best resource for any PHP needs

PHP.net/Manual Online and downloadable PHPmanual

Zend.com The Zend engine and plenty of usefuldocumentation

eclipse.org/pdt Eclipse PDT project, PHP

Development Tools PHPBuiler.com Tutorials, articles, forum

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