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PHP/MySQL Query

without comments

Somebody wanted an example of how to handle column values using PHP to query a MySQL database. While I thought there were enough examples out there, they couldn’t find one that was code complete.

Well, here’s one that works using a static query. If you want to use a prepared statement, check this earlier post.

<html>
<header>
<title>Static Query Object Sample</title>
<style type="text/css">
  /* HTML element styles. */
  table {background:white;border-style:solid;border-width:3px;border-color:black;border-collapse:collapse;}
  th {text-align:center;font-style:bold;background:lightgray;border:solid 1px gray;}
  td {border:solid 1px gray;}
 
  /* Class tag element styles. */
  .ID {min-width:50px;text-align:right;}
  .Label {min-width:200px;text-align:left;}
</style>
</header>
<body>
<?php
  // Assign credentials to connection.
  $mysqli = new mysqli("localhost", "student", "student", "studentdb");
 
  // Check for connection error and print message.
  if ($mysqli->connect_errno) {
    print $mysqli->connect_error."<br />";
    print "Connection not established ...<br />";
  }
  else {
 
    // Declare a static query.
    $query = "SELECT au.system_user_id, au.system_user_name FROM system_user au" ;
 
    // Loop through a result set until completed.  
    do {
 
      // Attempt query and exit with failure before processing.
      if (!$stmt = $mysqli->query($query)) {
 
        // Print failure to resolve query message.
        print $mysqli->error."<br />";
        print "Failed to resolve query ...<br />";
      }     
      else {
 
        // Print the opening HTML table tag.
        print '<table><tr><th class="ID">ID</th><th class="Label">User Role Name</th></tr>';
 
        // Fetch a row for processing.
        while( $row = $stmt->fetch_row() ) {
 
          // Print the opening HTML row tag.
          print "<tr>";
 
          // Loop through the row's columns.
          for ($i = 0;$i < $mysqli->field_count;$i++) {
            // Handle column one differently.
            if ($i == 0)
              print '<td class="ID">'.$row[$i]."</td>";
            else
              print '<td class="Label">'.$row[$i]."</td>";
          }
          // Print the closing HTML row tag.
          print "</tr>"; 
        }
      }
    } while( $mysqli->next_result());
 
  // Print the closing HTML table tag.
  print "</table>"; 
 
  // Release connection resource.
  $mysqli->close(); }
?>
</script>
</body>
</html>

It prints the following image:

While you shouldn’t embed CSS, I’ve done it to keep this as simple as possible. You can also use the procedural approach to the MySQLi library, like this:

<html>
<header>
<title>Static Query Procedural Sample</title>
<style type="text/css">
  /* HTML element styles. */
  table {background:white;border-style:solid;border-width:3px;border-color:black;border-collapse:collapse;}
  th {text-align:center;font-style:bold;background:lightgray;border:solid 1px gray;}
  td {border:solid 1px gray;}
 
  /* Class tag element styles. */
  .ID {min-width:50px;text-align:right;}
  .Label {min-width:200px;text-align:left;}
</style>
</header>
<body>
<?php
  // Assign credentials to connection.
  $mysqli = mysqli_connect("localhost", "student", "student", "studentdb");
 
  // Check for connection error and print message.
  if (mysqli_connect_errno()) {
    print mysqli_connect_error()."<br />";
    print "Connection not established ...<br />";
  }
  else {
 
    // Initialize a statement in the scope of the connection.
    $stmt = mysqli_stmt_init($mysqli);
 
    // Declare a static query.
    $query = "SELECT au.system_user_id, au.system_user_name FROM system_user au" ;
 
    // Loop through a result set until completed.  
    do { 
 
      // Attempt query and exit with failure before processing.
      if (!$stmt = mysqli_query($mysqli,$query)) {
 
        // Print failure to resolve query message.
        print mysqli_error($stmt)."<br />";
        print "Failed to resolve query ...<br />";
      }     
      else {
 
        // Print the opening HTML table tag.
        print '<table><tr><th class="ID">ID</th><th class="Label">User Role Name</th></tr>';
 
        // Fetch a row for processing.
        while( $row = mysqli_fetch_row($stmt) ) {
 
          // Print the opening HTML row tag.
          print "<tr>";
 
          // Loop through the row's columns.
          for ($i = 0;$i < mysqli_field_count($mysqli);$i++) {
            // Handle column one differently.
            if ($i == 0)
              print '<td class="ID">'.$row[$i]."</td>";
            else
              print '<td class="Label">'.$row[$i]."</td>";
          }
          // Print the closing HTML row tag.
          print "</tr>"; 
        }
      }
    } while( mysqli_next_result($mysqli));
 
    // Print the closing HTML table tag.
    print "</table>"; 
 
    // Free system resources.
    mysqli_stmt_free_result($stmt);
 
    // Release connection resource.
    mysqli_close($mysqli); 
  }
?>
</script>
</body>
</html>

It produces the same output as the object oriented approach with one exception the title of the web page.

Hope this helps some folks.

Written by maclochlainn

July 14th, 2012 at 11:59 pm

Posted in LAMP,MAMP,MySQL,PHP

Tagged with , ,

Implicit Commit Functions?

without comments

Somebody asked about the possibility of putting DML statements inside MySQL stored functions. DML statements like the INSERT, UPDATE, and DELETE. When I said, “Yes, you can put DML statements inside functions.” They showed me the error they encountered, which is only raised at compilation when you put an explicit COMMIT statement or a Data Definition Language (DDL) statement (CREATE, ALTER, DROP, or RENAME) inside a MySQL function. The actual error message displayed is:

ERROR 1422 (HY000): Explicit OR implicit commit IS NOT allowed IN stored FUNCTION OR TRIGGER.

While an explicit COMMIT is obvious when placed inside a function, the implicit COMMIT statement isn’t obvious unless you know a DDL statement generates one. This means you can’t include any DDL statement inside a stored function.

The following example shows how a DDL statement creates an immediate implicit COMMIT. It requires two sessions and Transaction Control Language (TCL) statements.

In session one, create a table, start a transaction scope, and insert one row into the table:

-- Create a table.
CREATE TABLE message
( message_id    INT UNSIGNED PRIMARY KEY AUTO_INCREMENT
, message_text  VARCHAR(20));
 
-- Start a transaction context.
BEGIN WORK;
 
-- Insert a row into the MESSAGE table.
INSERT INTO message (message_text) VALUES ('Implicit Commit?');

In session two, the empty set is displayed when you query the MESSAGE table. Returning to session one, add a new column to the MESSAGE table with this statement:

ALTER TABLE message ADD (sent DATETIME);

The ALTER statement automatically makes current any pending data changes, effectively committing the record from session one. You can return to the second session and query the table you get the following results:

+------------+------------------+------+
| message_id | message_text     | sent |
+------------+------------------+------+
|          1 | Implicit Commit? | NULL |
+------------+------------------+------+

When you embed DML statements inside functions, they rely on automatic commit behaviors or an external transaction scope. This function compiles and returns 1 when successful and 0 when unsuccessful, which effectively controls all error conditions within the function:

CREATE FUNCTION modifies_data ( pv_message  CHAR(20) ) RETURNS INT
MODIFIES SQL DATA
BEGIN
  /* Declare Boolean-like variables as FALSE. */
  DECLARE lv_return_value INT DEFAULT FALSE;
  DECLARE lv_error_value INT DEFAULT FALSE;
 
  /* Declare a generic exit handler to reset error control variable to true. */
  DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET lv_error_value := TRUE;   
 
  /* Insert statement with auto commit enabled. */
  INSERT INTO message (message_text) VALUES (pv_message);
 
  /* True unless the CONTINUE HANDLER disables the error control variable. */ 
  IF lv_error_value = FALSE THEN
    SET lv_return_value := TRUE;
  END IF;
 
  /* Return local variable. */
  RETURN lv_return_value;
END;
$$

With auto commit enabled, any call to the function in a query writes a row to the table. If you start a transaction and in the scope of the transaction test the function in one session and query the table in another you’ll see that transaction control can be managed outside the function. You can also manage the transaction control inside a stored procedure, which holds all the TCL commands. An example follows:

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CREATE PROCEDURE test_modifies_data ( pv_message  CHAR(20) )
MODIFIES SQL DATA
BEGIN
  /* Declare a control variable that manages transaction
     success or failure. */
  DECLARE lv_success_value  INT DEFAULT FALSE;
 
  /* Start a transaction context. */
  START TRANSACTION;
 
  /* Set a SAVEPOINT in the transaction context. */
  SAVEPOINT before_transaction;
 
  /* Call the function. */
  SET lv_success_value := modifies_data(pv_message);
 
  /* Check the status of the control variable, and commit
     or rollback the transaction. */
  IF lv_success_value = TRUE THEN
    COMMIT;
  ELSE
    ROLLBACK TO before_transaction;
  END IF;
 
END;
$$

Test the two with the following call to the procedure:

CALL test_modifies_data('Agent Coulson');

Answers my question and I hope it helps others.

Written by maclochlainn

June 5th, 2012 at 1:24 am

WebSockets Introduction

with 2 comments

The topic of WebSockets came up today, and it seems a good idea to qualify WebSockets in the blog beyond simply pointing folks to Kaazing. HTML5’s WebSockets are a great fix for the half-duplex world of AJAX. They certainly have the potential to be more scalable than current Comet solutions, and present a real-time communication alternative. The latest draft of The WebSocket API was published earlier this month.

If you’re new to WebSockets, you may want to review Peter Lubbers’ PowerPoint presentation from the International Conference on Java Technology, 2010 (or the updated version he provided via a comment to this post). That is probably shorter than watching the multiple parts posted in 10-minute segments on YouTube.

More or less the PDF file of the presentation covers how HTTP is half-duplex not full duplex, and why it doesn’t support real-time data in a browser. It points to AJAX (Asynchronous JavaScript and XML) as a programming nightmare – or more precisely a workaround to a limitation of HTTP/HTTPS. It also covers the idea of COMET programming or frameworks as complex and incomplete attempts to simulate full duplex or bi-directional communication on the web.

As Peter Lubbers qualifies, AJAX and COMET solutions don’t scale against high transaction volumes or concurrency because their header traffic overwhelms the actual data transfers. This reality occurs more or less because browsers only implement unidirectional communication through a request and acknowledgement model and send large header sequences compared to small data footprints.

Peter Lubbers presents three types of HTTP solutions in the presentation:

  • Polling involves periodic requests to the server for updated information, and it is the backbone of many Ajax applications that simulate real-time communication. The HTTP message headers involved in polling are frequently larger than the transmitted data; and while polling works well in low-message rate situations it doesn’t scale well. It also involves opening and closing many connections to the server and hence database needlessly in some cases.
  • Long Polling or asynchronous-polling requests the server to keep the connection open for a set period of time. It doesn’t solve problems with high-message rates situations of polling in general because it creates a continuous loop of immediate polls and each poll, like ordinary polling messages, sends mostly HTTP headers not data.
  • Streaming architecture opens a socket but can cause problems with proxy and firewall servers, create cross-domain issues due to browser connection limits, and periodically pose overhead to flush streams that have built up in the communication channel. Streaming solutions reduce HTTP header traffic but at a cost in overhead to the server.

Websockets are designed to fix these issues. The most interesting thing about polling, long polling, streaming, or Websockets is they require the same careful attention to how databases validate user access and serve up content. When the HTML5 standard nears completion, they’ll be a great need for database connection solutions, like Oracle’s Data Resident Connection Pooling.

By the way, here are some great video links for learning HTML5.

Written by maclochlainn

May 31st, 2012 at 11:59 pm

Fixing my.cnf on Fedora

with 5 comments

Working with a Fedora 16 VM for my students (next term) and found that the MySQL Server’s my.cnf file worked with a Linux socket as opposed to a listener port, and that several configuration options where missing from the file. Here’s the default /etc/my.cnf file after the package installation from the Red Hat site:

[mysqld]
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under different user or group,
# customize your systemd unit file for mysqld according to the
# instructions in http://fedoraproject.org/wiki/Systemd
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
 
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

Without rebuilding the log files, this seemed like the cleanest replacement for the MySQL Server my.cnf for a development instance running on Fedora 16. If you’ve other suggestions, please let me know.

[mysqld]
# Settings user and group are ignored when systemd is used.
# If you need to run mysqld under different user or group,
# customize your systemd unit file for mysqld according to the
# instructions in http://fedoraproject.org/wiki/Systemd
 
# Default directory.
datadir=/var/lib/mysql
 
# The TCP/IP Port the MySQL Server listens on.
# ------------------------------------------------------------
#   Find the machine's IP address with this command run as
#   the root user and use the port number specified in the
#   my.cnf file:
#   [root@localhost ~]# netstat -an | grep 3306
# ------------------------------------------------------------
 
bind-address=nnn.nnn.nnn.nnn
port=3306
 
# The Linux Socket the MySQL Server uses when not using a listener.
# socket=/var/lib/mysql/mysql.sock
 
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
 
# The default storage engine that will be used when creating new tables.
default-storage-engine=INNODB
 
# Set the SQL mode to strict.
sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
 
# Set the maximum number of connections.
max_connections=100
 
# Set the number of open tables for all threads.
table_cache=256
 
# Set the maximum size for internal (in-memory) temporary tables.
tmp_table_size=26M
 
# Set how many threads should be kept in a cache for reuse.
thread_cache_size=8
 
# MyISAM configuration.
myisam_max_sort_file_size=100G
myisam_sort_buffer_size=52M
key_buffer_size=36M
read_rnd_buffer_size=256K
sort_buffer_size=256K
 
# InnoDB configuration.
innodb_data_home_dir=/var/lib/mysql
innodb_additional_mem_pool_size=2M
innodb_flush_log_at_trx_commit=1
innodb_log_buffer_size=1M
innodb_buffer_pool_size=25M
innodb_log_file_size=5M
innodb_thread_concurrency=8
 
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

As always, I hope this helps somebody.

Written by maclochlainn

December 7th, 2011 at 1:15 am

MySQL and Java Tutorial

with 2 comments

This demonstrates how to create an Java infrastructure for reading and writing large text files to a MySQL database. The example provides:

  • A FileIO.jar library that lets you enter MySQL connection parameters through a JOptionPane, and a customized JFileChooser to filter and read source files from the file system.
  • A mysql-connector-java-3.1.14-bin.jar file, which is MySQL’s library for JDBC communication with the MySQL Databases.

The steps to compiling and testing this code are qualified below:

  1. Download and install the Java Software Development Kit (JSDK) for Java 6.
  2. Create a C:\JavaTest folder on Windows, or a /JavaTest directory from some mount point of your choice.
  3. Download and position the mysql-connector-java-3.1.14-bin.jar and FileIO.jar files in the JavaTest directory.
  4. Create a batch file to source your environment path (%PATH% on Windows and $PATH on Linux or Mac OS X) and the two Java Archive (JAR) files. A sample batch file is noted below:
set PATH=C:\Program Files\Java\jdk1.6.0_07\bin;%PATH%
set CLASSPATH=C:\JavaDev\Java6\mysql-connector-java-3.1.14-bin.jar;C:\JavaDev\Java6\FileIO.jar;.

You can run this file by simply typing the files first name. On Linux or Mac OS X, you first need to grant it privileges with the chmod command as 755.

  1. Copy the WriteReadCLOBMysql.java code from the bottom of this posting and also put it into the JavaTest directory.
  2. Compile the WriteReadCLOBMysql.java source code with the javac utility, as shown below:
javac WriteReadCLOBMysql.java

After you compile it, you should run it as follows:

java WriteReadCLOBMysql
  1. Before running the code, you’ll need to seed (INSERT) a row that meets the desired hard coded criteria. It requires an ITEM_TITLE value of 'The Lord of the Rings - Fellowship of the Ring' and an ITEM_SUBTITLE of 'Widescreen Edition' in the ITEM table.
  2. When it runs, you’ll see the following tabbed JOptionPane.

You need to enter the following values before clicking the OK button:

  • Host: The localhost key word, or hostname of your physical machine running the database.
  • Port: The port that the MySQL Listener is running on (the default value is 3306).
  • Database: The Oracle TNS Alias, which is sampledb for the full database sample database.
  • UserID: The user name with permissions to the database entered that can access an ITEM table.
  • Password: The password for the user’s account.

In the JFileChooser, select a file to upload to the database.

You should see what you uploaded displayed in a JFrame.

Written by maclochlainn

November 14th, 2011 at 4:49 pm

Posted in Java,LAMP,MAMP,MySQL

Configure Fedora on VMWare

with 4 comments

It seems Fedora is always a bit of work. You begin by mistakenly downloading Fedora Live, which isn’t really the product but a run-time demonstration product. After finding the product, if you choose a full installation, there are post installation steps to complete. The first time you launch it in VMWare, you’ll see a Gnome 3 Failed to Load error dialog like this:

I suspected that installing VMWare Tools would fix that, and it did. However, your entry account doesn’t have “sudoers” permissions. You must add them before you can run VMWare Tools. There are six steps to enable your user with the sudoers permissions and four others to configure the standard installation:

  1. Navigate to the Applications menu choice in the upper left hand corner. You’ll get the following drop-down menu. Click on Other menu item to launch a dependent floating menu.

  1. The following floating menu displays to the right. Click on Users and Groups menu item at the bottom of the list.

  1. The choice from the floating menu prompts account validation. Enter your password and click the OK button.

  1. After validating your password, the User Manager dialog opens. Click on the single user that should be installed – mclaughlinm. Click the Properties button to change the groups assigned to the user.

  1. The User Properties dialog opens with the default User Data tab clicked. Click on the Groups tab to add the user to the wheel group as a property of your user.

  1. Scroll down through the list of groups and click the wheel group check box. Like the Mac OS, the wheel group provides “sudoer” privileges. Click the OK button to assign the group to the user.

  1. Navigate to the VMWare Menu, choose Virtual Machine and in the drop down menu Install VMWare Tools. This will mount a virtual CD in the Fedora virtual machine.

  1. Navigate to the Places menu choice and then Computer. Inside the Computer, choose the VMware Tools from the Devices section and you’ll see the following:

  1. Open a terminal session by choosing Applications, within the drop down choose System Tools, and then launch a Terminal session. You can then run the VMWare Toolkit by following these instructions:
cd /media/VMware\ Tools
cp VMwareTools-8.4.7-416484.tar.gz /tmp
cd /tmp
gunzip VMwareTools-8.4.7-416484.tar.gz
tar -xvf VMwareTools-8.4.7-416484.tar
cd vmware-tools-distrib
sudo ./vmware-install.pl

The last step requires that you reply to a set of prompts. If you’d like to accept the default at one time, you can use the following command:

sudo ./vmware-install.pl --default

If you find limited access to the system after installing or upgrading VMWare Tools, you may have packages in the caught between start and finish. You can clean them up with the following syntax, as the root user:

sudo yum-complete-transaction
  1. In the terminal session you should configure three files to make sure your networking works. I found that the dialogs failed to set one key element, so it’s simply easier to do this manually. Rather than using sudo, you should open a root shell with the following command:
sudo sh

Enter your user’s password:

[sudo] password for mclaughlinm:

You should use vi to edit and save the resolv.conf file with appropriate domain, search, and nameserver values. The values below work for VMWare when the gateway IP address is 172.16.123.2.

# Generated by NetworkManager
domain localdomain
search localdomain
nameserver 172.16.123.2

Using vi, edit the /etc/sysconfig/network file to include an appropriate gateway IP address, like so:

NETWORKING=yes
HOSTNAME=localhost.localdomain
GATEWAY=172.16.123.2

The last file to fix is /etc/sysconfig/network-scripts/ifcfg-eth0 file. This is the file that isn’t completely configured by the GUI component (it fails set the ONBOOT value to yes).

DEVICE=eth0
HWADDR=00:0c:29:31:ef:46
ONBOOT=yes
NM_CONTROLLED=yes
BOOTPROTO=dhcp
TYPE=Ethernet
DNS1=172.16.123.2
USERCTL=no
PEERDNS=yes
IPV6INIT=no

You reset networking with the following command:

/etc/rc.d/init.d/network restart

As always, I hope this helps a few folks.

Written by maclochlainn

September 25th, 2011 at 10:40 pm

Posted in Fedora,LAMP,Linux,Red Hat

Create a synonym in MySQL

with 3 comments

A friend wanted to know how to create a synonym to a library of stored functions and procedures in MySQL. I had to deliver the sad news that you can’t create a synonym in MySQL 5.0, 5.1, or 5.5. You need to write a wrapper function or procedure.

A synonym (available in Oracle) would eliminate the need to call a function from another database through the component selector (or period). That’s because it maps a name to the reference and name instead of requiring you to include it with each call. The following shows a call from outside of the lib database:

SELECT lib.demo('Hello World!') AS "Statement";

He asked how to do it, so here’s how you do it below. Assume the following for this example:

  • You have a lib database where you define all your functions, procedures, and tables.
  • You have a app database that supports web connections.
  • You don’t want to allow web users to connect directly to the lib database because access to the tables should only be available through the functions and procedures.

This base function is simplified to avoid interaction with table data but illustrate the technique of definer rights functions. The function takes a string of up to 20 characters and returns it enclosed in double quotes. To mimic these behaviors, as the root user, you should create the app and lib databases, the dev and web users, and grant privileges to the dev user to act in the lib database and the web user to act in the app database. The example below does this as the root user, but in real life don’t use a trivial password like the example:

/* Create the two databases. */
CREATE DATABASE app;
CREATE DATABASE lib;
 
/* Create the two users, the developer can only connect locally. */
CREATE USER 'dev'@'localhost' IDENTIFIED BY 'dev';
CREATE USER 'web'@'%' IDENTIFIED BY 'web';
 
/* Grant privileges to be a definer in both databases. */
GRANT ALL ON app.* TO 'dev'@'localhost';
GRANT ALL ON lib.* TO 'dev'@'localhost';
 
/* Grant privileges to any function or privilege in the APP database to the WEB user. */
GRANT EXECUTE ON app.* TO 'web'@'%';

After creating and granting all the appropriate privileges, here are the steps to create the test case.

  1. You create and test the function as the dev user in the lib database.
/* Set the delimiter to something other than a semi-colon so they can be typed in statements. */
DELIMITER $$
 
/* Create a function that echoes back the string with double quotes. */
CREATE FUNCTION demo(str VARCHAR(20)) RETURNS VARCHAR(20)
BEGIN
  RETURN CONCAT('"',str,'"');
END;
$$
 
/* Reset the DELIMITER value. */
DELIMITER ;
 
/* Query the function. */
SELECT demo('Ciao amico!') AS "Statement";
  1. You create and test the wrapper function as the dev user in the app database.
/* Set the delimiter to something other than a semi-colon so they can be typed in statements. */
DELIMITER $$
 
/* Create a function that echoes back the string with double quotes. */
CREATE FUNCTION demo(str VARCHAR(20)) RETURNS VARCHAR(20)
BEGIN
  RETURN lib.demo(str);
END;
$$
 
/* Reset the DELIMITER value. */
DELIMITER ;
 
/* Query the function. */
SELECT demo('Ciao amico!') AS "Statement";

If you’re wondering why a GRANT wasn’t required from the lib database to the app database, it’s because the dev user has access to both databases and defined both objects.

  1. You can test the wrapper function as the web user in the app database.
SELECT demo('Yes, it works!') AS "Statement";

This is the closest to a synonym for a function or procedure that is possible. I know this solves his problem and hope it solves a couple others too.

Written by maclochlainn

February 5th, 2011 at 11:02 pm

PHP leveraging PL/SQL

with one comment

Somebody wanted another example of how to leverage a true/false condition from a PL/SQL stored function in PHP. The first key is that you write the function as if you were using it in SQL not PL/SQL. That means you return a NUMBER data type not a PL/SQL-only BOOLEAN data type.

Here’s the schema-level PL/SQL function:

CREATE OR REPLACE FUNCTION like_boolean
( a NUMBER, b NUMBER ) RETURN NUMBER IS
 
  /* Declare default false return value. */
  lv_return_value NUMBER := 0;
 
BEGIN
 
  /* Compare numbers and return true for a match. */
  IF a = b THEN
    lv_return_value := 1;
  END IF;
 
  /* Return value. */
  RETURN lv_return_value;
 
END;
/

Here’s the PHP that leverages the PL/SQL in an if-statement on line #24:

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<?php
  // Capture local variables when provided.
  $thingOne = (isset($_GET['thingOne'])) ? $_GET['thingOne'] : 1;
  $thingTwo = (isset($_GET['thingTwo'])) ? $_GET['thingTwo'] : 1;
 
  // Open a connection.
  if(!$c = oci_connect("student","student","localhost/xe"))
  {
    die;
  }
  else
  {
 
    // Parse a statement.  
    $s = oci_parse($c,"BEGIN
                         :returnValue := LIKE_BOOLEAN(:thingOne,:thingTwo);
                       END;");
 
    // Bind input and output values to the statement.
    oci_bind_by_name($s,":returnValue",$returnValue);
    oci_bind_by_name($s,":thingOne",$thingOne);
    oci_bind_by_name($s,":thingTwo",$thingTwo);
 
    // Execute the statement.
    if (@oci_execute($s))
    {
      // Print lead in string.
      print "[".$thingOne."] and [".$thingTwo."] ";  
      if ($returnValue)
        print "are equal.<br />";
      else
        print "aren't equal.<br />";
    }
 
    // Clean up resources.
    oci_close($c);
  }
?>

If you run into a parsing error, which is infrequent now. You can wrap the multiple row PL/SQL anonymous block call with this function. It strips tabs and line returns. Alternatively, you can put all the lines of PL/SQL on a single line.

  // Strip special characters, like carriage or line returns and tabs.
  function strip_special_characters($str)
  {
    $out = "";
    for ($i = 0;$i < strlen($str);$i++)
      if ((ord($str[$i]) != 9) && (ord($str[$i]) != 10) &&
          (ord($str[$i]) != 13))
        $out .= $str[$i];
 
    // Return pre-parsed SQL statement.
    return $out;
  }

If you run into a parsing problem on Oracle XE 10g, you can wrap the PL/SQL call like the following. Alternatively, you can place the entire anonymous PL/SQL block on a single line without embedded tabs or return keys..

10
11
12
13
  $s = oci_parse($c,strip_special_characters(
                    "BEGIN
                       :returnValue := LIKE_BOOLEAN(:thingOne,:thingTwo);
                     END;"));

Hope that answers the question and helps some folks.

Written by maclochlainn

December 22nd, 2010 at 11:53 pm

Posted in LAMP,OPAL,Oracle,PHP,pl/sql

Tagged with , , ,

PHP Database Authentication

with one comment

A few years ago I wrote a couple articles showing how to use PHP to connect to an Oracle Database 10g Express Edition instance. They’re still there on Oracle’s Technical Network but the source files are missing. It appears that Oracle may have migrated the articles to a new server but failed to migrate the source files.

Don’t forget that you’ll need to Install the Zend Community Server. Then, you need to create an IDMGMT1, IDMGMT2, and IDMGMT3 users and run the create_identity_db2.sql or create_identity_db3.sql seeding script for both database validation models. You’ll find links to the original articles, the source code in zip files. The newer version with CSS is the IDMGMT3 code.

The CSS sign-on form looks like this:

The portal page looks like this:

The add new user page looks like this:

The source files are as follows:

  1. Database Authentication #1IdMgmt1.zip
  2. Database Authentication #2IdMgmt2.zip
  3. Database Authentication #3IdMgmt3.zip includes the CSS but works with the same write-up as Idmgmt2.

Hope this helps those who wanted the files.

Written by maclochlainn

December 19th, 2010 at 1:44 am

MySQL Sunday

without comments

The merry-go-round is running and Oracle Open World 2010 has begun with MySQL Sunday. The merry-go-round is a fixture at the northwest corner of the Moscone South building, at the intersection shared between the Moscone North building.

The keynote was interesting because Oracle confirmed that they have and will continue to invest in MySQL. The MySQL 5.5 Candidate Release is now available for download. Key features that you’ll note are 200% to 300% improved performance, the InnoDB is now the default engine, backup and recovery are dramatically improved, and the enterprise model is integrated to provide more information about internals and performance.

A little research for the comprehensive new feature list for MySQL 5.5 found a well documented page in the MySQL 5.5 Reference. Examples of things left out of the presentation, not an inclusive list of all features, are: improved operation on the Solaris platform (surprise ;-)), support for semisynchronous replication, support for SQL standard SIGNAL and RESIGNAL statements, support for Unicode character sets, a LOAD XML statement, expanded partitioning options – including the ability to truncate only a partition of a table, and may new command options.

Ronald Bradford gave a good presentation on MySQL idiosyncrasies. I thought spelling out behaviors common to Windows and Mac platforms that differ from Linux and Unix platforms was great. He’s got a new book that he co-authored on MySQL and PHP. I’ve look into the book yet.

I also enjoyed Giuseppe Maxia’s presentation on partitioning. His regular web site is here, but beware if you’ve a slow web connection because the photos delay page loading. ;-)

Update on MySQL Sunday

Here are some links provided by Oracle to presentations:

  • Edward Screven’s presentation
  • Live Webinar: “Delivering Scalability and High Availability with MySQL 5.5 Replication Enhancements

Written by maclochlainn

September 19th, 2010 at 2:30 pm

Posted in InnoDB,LAMP,MAMP,MySQL