When I started using PostgreSQL, it seemed odd that when I created a table called Users with column names like userId, userPassword, etc. When I would select these items from the table, the column and table names would all be in lowercase. It's quite simple really, I wasn't using quotes :) Below is an example of how to maintain your case in PostgreSQL:

This will all come out lowercase

create table Users (
  userId integer unique not null,
  userFirstName varchar(50) not null,
  userLastName varchar(50) not null
);

Whereas this will come out as you expect it to

create table "Users" (
  "userId" integer unique not null,
  "userFirstName" varchar(50) not null,
  "userLastName" varchar(50) not null
);

This is a super simple implementation of a concept found here:
http://xtech06.usefulinc.com/schedule/paper/19

This xml class provides a very simple way to open an XML file, get information from the XML file, modify information from the XML file and save the XML file. It also supports automatic creation of new XML files based on an automatically incrementing ID senerio (similar to auto incrementing primary keys in databases).

The creation of new XML files is done by looking for a "template" xml file named 0.xml in the directory passed to the create function. If the template file is found, then it is loaded into the xml class and saved to a new file whose name is one more than the highest filename (of course the xml extension is added on). Eventually, I will try and add some validation code and whatever else, but for now I'm trying to keep things simple.

This requires the DOM module to be built into PHP.
I am using PHP 5.

If anyone has any ideas on how to improve this, feel free to post comments.

<?php

class xml
{
	var $dom;
	var $uri;

	function xml($uri)
	{
		$this->dom = new DOMDocument();

		if(preg_match('/\.xml$/', $uri))
		{
			$this->uri = $uri;
		}
		else
		{
			$this->uri = $this->create($uri);
		}
		$this->dom->load($this->uri);
	}

	function set($query, $value)
	{
		$path = new DOMXPath($this->dom);
		$nodes = $path->query($query);
		$nodes->item(0)->nodeValue = $value;
	}

	function get($query)
	{
		$path = new DOMXPath($this->dom);
		$nodes = $path->query($query);
		return $nodes->item(0)->nodeValue;
	}

	function save()
	{
		$this->dom->save($this->uri);
	}

	function create($uri)
	{
		// Build the URI of the template file.
		$template = sprintf('%s/0.xml', $uri);

		// If the directory doesn't exist, we can't really
		// do anything.
		if(!is_dir($uri))
		{
			exit('No directory');
		}

		// If the template file doesn't exist, we cannot
		// create a new file automatically.
		if(!file_exists($template))
		{
			exit('No template');
		}

		// Load the template XML into our DOMDocument.
		$this->dom->load($template);

		// Scan the directory into an array.
		$dir = scandir($uri);

		// Pull out the highest ID
		$id = str_replace('.xml', '', array_pop($dir));

		// Add one to it
		$id++;

		// Construct the new path with the new ID
		$uri = sprintf('%s/%s.xml', $uri, $id);

		// Save the new file
		$this->dom->save($uri);

		// Return the URI of the new XML file.
		return $uri;
	}
}

// The following code will create a new XML file
// under the directory /var/www/data/users.
$x = new xml('/var/www/data/users');
$x->set('//user/name', 'John Doe');
$x->save();

?>

In order to utilize this, I would recommend reading the article located at sitepoint.com (Search google for modified preorder tree traversal). It took me quite some time and some help from a coworker to port this from PHP to VB.net. :D

Replace the application("sql").query("*") with your SQL code, I was inclined to write my own SQL class to make querying DB's easier, but you can do whatever you want.

record = application("sql").query("select * from categories order by lft asc")
dim output as new arraylist()
dim right as new arraylist()
do while not record.eof
  if right.count > 0
    do while right(right.count - 1) < record("rgt").value
      right.removeAt(right.count - 1)
      if right.count = 0 then exit do
    loop
  end if
  response.write(record("name").value & " is " & right.count & " levels deep in the tree..." & controlchars.cr)
  right.add(record("rgt").value)
  record.movenext
loop

This SQL statement will alter a table only if a column in the table to be altered does NOT contain a column named 'FavoriteColorId'.

From: http://haacked.com/

IF NOT EXISTS
(
    SELECT * FROM [information_schema].[columns]
    WHERE    table_name   = 'Customer'
    AND      table_schema = 'dbo'
    AND      column_name  = 'FavoriteColorId'
)
BEGIN
    ALTER TABLE [dbo].[Customer]
    ADD FavoriteColorId int