Comparison with MySQL

Transcription

1 Element and Attribute IT 3203 Introduction to Web Development Databases, and the Web April 21 Notice: This session is being recorded. Copyright 2007 by Bob Brown Databases and Programming Languages General approach: Construct SQL statements in a variable Pass SQL commands to the DBMS with an API Retrieve the results with an API (function) Process the results Comparison with is more often found on servers than. If you can do, you can do For greatest portability, learn to use PEAR::DB (not studied here) Connect String Connect String $db_handle = pg_connect("host=sheep port=5432 dbname=test user=lamb password=xyzzy"); Connect to a database. Keyword oriented. $db_handle=mysql_connect ( [string server [, string username [, string password [, bool new_link [, int client_flags]]]]]) Connect to a server. Positional. You must then select a database. Remember, is your friend 1

2 Connect to Database $db_handle=pg_connect("dbname=webdev") or die("could not connect: ". pg_last_error()); $db_handle = mysql_connect("webdev", "bbrown", "xyzzy") or die("could not connect: ". mysql_error()); mysql_select_db("webdev") or die("could not select database"); Connect and Select in The call to mysql_connect names the server. The call to mysql_select names the database. In this class, confusingly, they both have the same name, i.e. the database webdev on server webdev. Build Query String $query="select * from hardware_t;"; $query="select * from hardware_t;"; Yup, they re identical. Execute the Query $db_result = pg_query($query); if (!$db_result) die("query failed: ". pg_last_error()); $db_result = mysql_query($query); if (!$db_result) die("query failed: ". mysql_error()); Get Number of Rows $num=pg_num_rows($db_result); $num=mysql_num_rows($db_result); Process Result Rows for ($i=0; $i<$num; $i++) { $row=pg_fetch_assoc($db_result, $i); for ($i=0; $i<$num; $i++) { $row=mysql_fetch_assoc($db_result, $i); 2

3 A Shortcut to Row Processing while ($row=pg_fetch_assoc($dbresult)) { while ($row=mysql_fetch_assoc($dbresult)) { If You Can Do You can do. With the exception of selecting a database in, the differences are almost entirely in the function names. This is for PHP; other languages might be less similar. Look up Professor James Hendler 3

4 Information Architecture and the Enterprise Economies Don t Always Scale Large organizations need: Consistent processes Clear and consistent communications The purpose of an organization is to coordinate the efforts of many people. However, technology drives decentralization. The Decentralizing Nature of Technology Compare and contrast: A personal Web site A corporate or university Web site Building a Web page is easy Everyone in the enterprise will want to do it They will all be different! 4

5 The Corporate Portal Model Problems Where to begin? Silos of information Same concept, different labels Different concept, same labels Inconsistent navigation systems Ignorance is not bliss! The cost of finding information The cost of not finding information Inconsistent information The Case for Centralization Increased Revenues Reduced Costs Clearer Communication Shared Expertise Centralization is Inevitable Anyway (?) 5

6 Roadblocks to Centralization Unrealistic Scheduling No Stone Unturned The Monolithic Effort Human Nature Ignored Insufficient Support A Framework for Centralization A New Business Unit Phasing In Strategy and Tactics A New Business Unit Establish, with support of senior management, a business unit for IA and content management. Become a service provider. Become self-supporting. Offer basic services free (For consultants, this is pitching. ) Bill for premium services. Billing limits demand. (Good.) A Phased Rollout You cannot do everything all at once. Identify the best clients Content Users Context You will have to sell your services! A client information checklist Projecting demand Strategy and Tactics Separate strategy and tactics Strategy Strategic alignment Financial and political stability Management and performance Tactics Implementing IA for clients Questions 6