Copyright © 2011 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Chapter 13 &14 Intro to SQL Programming Techniques & Web DB + PhP

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Introduction to SQL Programming Techniques  Database applications  Host language Java, C/C++/C#, COBOL, or some other programming language  Data sublanguage SQL  SQL standards  Continually evolving  Each DBMS vendor may have some variations from standard

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Approaches to Database Programming (cont’d.)  Using a library of database functions  Library of functions available to the host programming language  Application programming interface (API)  Designing a brand-new language  Database programming language designed from scratch  First two approaches are more common

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Impedance Mismatch  Differences between database model and programming language model  Binding for each host programming language  Specifies for each attribute type the compatible programming language types  Cursor or iterator variable  Loop over the tuples in a query result

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Typical Sequence of Interaction in Database Programming  Open a connection to database server  Interact with database by submitting queries, updates, and other database commands  Terminate or close connection to database

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Embedded SQL, Dynamic SQL, and SQLJ  Embedded SQL  C language  SQLJ  Java language  Programming language called host language

Copyright © 2011 Ramez Elmasri and Shamkant Navathe JDBC: SQL Function Calls for Java Programming  JDBC  Java function libraries  Single Java program can connect to several different databases  Called data sources accessed by the Java program  Class.forName("oracle.jdbc.driver.OracleDriver")  Load a JDBC driver explicitly

Copyright © 2011 Ramez Elmasri and Shamkant Navathe

JDBC: SQL Function Calls for Java Programming  Connection object  Statement object has two subclasses:  PreparedStatement and CallableStatement  Question mark ( ? ) symbol  Represents a statement parameter  Determined at runtime  ResultSet object  Holds results of query

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Chapter 14 Outline  A Simple PHP Example  Overview of Basic Features of PHP  Overview of PHP Database Programming

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Web Database Programming Using PHP  Techniques for programming dynamic features into Web  PHP  Open source scripting language  Interpreters provided free of charge  Available on most computer platforms

Copyright © 2011 Ramez Elmasri and Shamkant Navathe A Simple PHP Example  PHP  Open source general-purpose scripting language  Comes installed with the UNIX operating system

Copyright © 2011 Ramez Elmasri and Shamkant Navathe A Simple PHP Example (cont’d.)  DBMS  Bottom-tier database server  PHP  Middle-tier Web server  HTML  Client tier

Copyright © 2011 Ramez Elmasri and Shamkant Navathe A Simple PHP Example (cont’d.) Client Tier Middle-tier Web Server Database Server

Copyright © 2011 Ramez Elmasri and Shamkant Navathe

A Simple PHP Example (cont’d.)  Example Figure 14.1(a)  PHP script stored in:   <?php  PHP start tag  ?>  PHP end tag  Comments: // or /* */

Copyright © 2011 Ramez Elmasri and Shamkant Navathe A Simple PHP Example (cont’d.)  $_POST  Auto-global predefined PHP variable  Array that holds all the values entered through form parameters  Arrays are dynamic  Long text strings  Between opening <<<_HTML_ and closing _HTML_;

Copyright © 2011 Ramez Elmasri and Shamkant Navathe A Simple PHP Example (cont’d.)  PHP variable names  Start with $ sign

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Overview of Basic Features of PHP  Illustrate features of PHP suited for creating dynamic Web pages that contain database access commands

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Variables, Data Types, and Programming Constructs  PHP variable names  Start with $ symbol  Can include characters, letters, and underscore character ( _ )  Main ways to express strings and text  Single-quoted strings  Double-quoted strings  Here documents  Nowdoc (PHP and later)

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Variables, Data Types, and Programming Constructs (cont’d.)  Period (.) symbol  String concatenate operator  Single-quoted strings  Literal strings that contain no PHP program variables, no parsing/escaping except \’, \\  Double-quoted strings and here documents  Values from variables need to be interpolated into string

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Variables, Data Types, and Programming Constructs (cont’d.)  Numeric data types  Integers and floating points  Programming language constructs  For-loops, while-loops, and conditional if- statements  Boolean expressions

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Variables, Data Types, and Programming Constructs (cont’d.)  Comparison operators  == (equal), != (not equal), <> (not equal) > (greater than), >= (greater than or equal), < (less than), and <= (less than or equal)  ===, !== (equal and not equal without type juggling)  Type juggling will convert strings to numbers if possible

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Arrays  Database query results  Two-dimensional arrays  First dimension representing rows of a table  Second dimension representing columns (attributes) within a row  Main types of arrays:  Numeric and associative

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Arrays (cont’d.)  Numeric array  Associates a numeric index with each element in the array  Indexes are integer numbers Start at zero Grow incrementally  Associative array  Provides pairs of (key => value) elements

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Arrays (cont’d.)

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Arrays (cont’d.)  Techniques for looping through arrays in PHP  Count function  Returns current number of elements in array  Sort function  Sorts array based on element values in it

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Functions  Functions  Define to structure a complex program and to share common sections of code  Arguments passed by value  Examples to illustrate basic PHP functions  Figure 14.4  Figure 14.5

Copyright © 2011 Ramez Elmasri and Shamkant Navathe

PHP Functions (cont’d.)

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Server Variables and Forms  Built-in entries  $_SERVER auto-global built-in array variable  Provides useful information about server where the PHP interpreter is running

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Server Variables and Forms (cont’d.)  Examples: $_SERVER['SERVER_NAME'] $_SERVER['REMOTE_ADDRESS'] $_SERVER['REMOTE_HOST'] $_SERVER['PATH_INFO'] $_SERVER['QUERY_STRING'] $_SERVER['DOCUMENT_ROOT']  $_POST  Provides input values submitted by the user through HTML forms specified in tag

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Including Files  include “./path/to/file.php”;  Attempts to copy the contents of file.php to the specified path  No code included if not found, but script continues execution  include_once  Equivalent to include but checks to see if the file has already been included first  If file is present, execution continues

Copyright © 2011 Ramez Elmasri and Shamkant Navathe PHP Including Files (cont’d.)  require “./path/to/file.php”;  Attempts to copy the contents of file.php to the specified path  If file is not found, PHP throws an error and execution stops  require_once “./path/to/file.php”;  Equivalent to require but checks to see if the file has already been included first  If file is present, execution continues

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Object Oriented PHP  Use the class keyword to declare a new class  Declare variables private/public/protected  Declare a new object with the new keyword  Use -> to access functions  Eg. $some_object->my_function();

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Object Oriented PHP (cont’d.)

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Debugging PHP  var_dump($var)  Prints the content of the variable $var into the output  Also prints variable type information  Prints out all values in nested arrays/objects  Third party libraries  Kint prints out formatted info in a tree-like format

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Debugging PHP (cont’d.)

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Overview of PHP Database Programming  PEAR DB library  Part of PHP Extension and Application Repository (PEAR)  Provides functions for database access

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Connecting to a Database  Library module DB.php must be loaded  DB library functions accessed using DB::  DB::connect('string')  Function for connecting to a database  Format for 'string' is: ://

Copyright © 2011 Ramez Elmasri and Shamkant Navathe

Connecting to a Database (cont’d.)  Query function  $d->query takes an SQL command as its string argument  Sends query to database server for execution  $d–>setErrorHandling(PEAR_ERROR_DIE)  Terminate program and print default error messages if any subsequent errors occur

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Collecting Data from Forms and Inserting Records  Collect information through HTML or other types of Web forms  Create unique record identifier for each new record inserted into the database  PHP has a function $d–>nextID to create a sequence of unique values for a particular table  Placeholders  Specified by ? symbol

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Retrieval Queries from Database Tables  $q  Query result  $q->fetchRow() retrieve next record in query result and control loop  $d->getAll  Holds all the records in a query result in a single variable called $allresult

Copyright © 2011 Ramez Elmasri and Shamkant Navathe

Summary  PHP scripting language  Very popular for Web database programming  PHP basics for Web programming  Data types  Database commands include:  Creating tables, inserting new records, and retrieving database records

Copyright © 2011 Ramez Elmasri and Shamkant Navathe NEED TO ADD – USING REST APIs SLIDES

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Project Phase II Instructions  Download XAMPP  XAMPP includes: Apache, PHP, MySQL, and other goodies. No need to download and install them separately, XAMPP does it all.  Download:  FAQs (Includes instructions on how to install it and set it up): Windows FAQs: OSX FAQs: Linux FAQs:

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Project Phase II Instructions  Download Aptana Studio  Aptana Studio is a web development IDE rooted on Eclipse. You can use your preferred IDE for the project, it does not need to be Aptana.  Download:  You can download Aptana Studio 2, 3 or either as an Eclipse plugin. For the instructions on this guide, we will use the standalone (not the Eclipse plugin) version of Aptana Studio 3.

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Project Phase II Instructions  Sample API (Slim Framework)  Slim is a PHP micro framework that helps you quickly write simple yet powerful web applications and APIs.  Slim Framework documentation:  See : TBD  Sample GUI Web-App (for CRUD operations)  A sample CRUD (Create, Read, Update, Delete) web- app that interfaces with the MySQL database to use.  See : TBD

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Setting up a Sample DB  XAMPP bundles in PhpMyAdmin (

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Set PhpMyAdmin web-app  Go to:  If you don’t use Port 80 – Use where {yourport} is the custom port.

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Setting up the Sample API  Add sample_api, to you XAMPP’s htdocs folder  With sample_api in place:  Open Aptana Studio (or your IDE)  Click File -> Import  Select Existing Folder as New Project  Select a folder. Navigate to your C:/xampp/htdocs/sample_api folder  Give the project a name  Select PHP and Web - Primary as the project types  Click on Finish

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Sample_gui – customers.php

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Sample_gui – customers.php

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Sample_api – index.php

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Sample_api – index.php

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Sample_api – index.php

Copyright © 2011 Ramez Elmasri and Shamkant Navathe Sample_api – index.php