MySQL: Error 1305 - Function xxx does not exist

I ran into an odd issue on a project I updated awhile ago. I updated an existing sql statement to include IFNULL for an exclusion check. It worked fine on my dev machine, but caused an issue on the production machine.

The version of MySQL on my dev machine was a little bit newer than production so the issue never came up. Here is the error the sql server returned:
#1305 - FUNCTION [DATABASE_NAME].ifnull does not exist

Here is a little bit of the sql that caused the error:
AND IFNULL ( `tbl_category_admin`.`admin_key_id` =5, true )

The problem was caused by the space between IFNULL and (. Changing it to IFNULL( solved the problem. If you run into an issue where MySQL returns an error saying a given function does not exist look for spaces between the function and the "(".

Flex (Learning Flex 3 Book) : Removing IEventDispatcher error from the DataGrid

When I decided to learn Flex I started with Learning Flex 3. It's a great book and does an excellent job of introducing the MXML framework and Flex Builder IDE. I would recommend it to anyone.

One of the problems I have with the book is it doesn't teach you how to remove warnings from your code. A later code example produces the following error: warning: unable to bind to property 'contact' on class 'XML' (class is not an IEventDispatcher). It's not a big deal, but I like to write code that doesn't produce hidden errors.

Here is the code from the book:

<mx: Application
    xmlns: mx="http: //www.adobe. com/2006/mxml"
    xmlns: view="com.oreilly.view.*"
    layout="absolute"
    applicationComplete="contactsService.send()" >
    <mx:HTTPService id="contactsService"
        resultFormat="e4x"
        url="contacts.xml" />
    <mx:DataGrid id="contactsDataGrid"
        dataProvider="{contactsService.lastResult.contact}"
        selectedIndex="0"
        left="10"
        top="10"
        bottom="10"
        width="300">
        <mx: columns>
            <mx: DataGridColumn headerText="First"  
            dataField="firstName"/>
            <mx: DataGridColumn headerText="Last" dataField="lastName"/>
        </mx:columns>
    </mx:DataGrid>
    <view: ContactViewer
        contact="{contactsDataGrid. selectedItem}"
        x="318" y="10">
    </view: ContactViewer>
</mx: Application>

The problem is the dataProvider property of DataGrid. It's unable to figure out how to parse the data, so it throws a warning. This can be resolved with casting. We can tell the dataProvider what it should be and it will remove the warning. Here is the code that will remove the warning.

dataProvider="{XMLList(XML(contactsService.lastResult).contact)}"

contactsService.lastResult is an XML object. There are multiple children in the object. We can then cast the XML object as an XMLList to use contact child node.

Feel free to leave a comment if you have any questions.

Flex: New Project Settings

When starting a new Flex project there are a few settings I like to use by default.

Changes to Flex Compiler
Flex Compiler options for a project can be found by right-clicking the project and selecting properties. Select Flex Compiler from the menu on the left. The following properties should be added to the Additional compiler arguments field.

When you're reading local xml files or image you might run into a sandbox security Error# 2140 or ReferenceError Error# 1069 using the HTTPService object. Use this switch to stop the error.
-use-network=false


The loading background color of a Flex app can be changed. Use this switch to change the property.
-default-background-color [HTML COLOR VALUE]
I typically use #FFFFFF.


Changes to the Application
I like to use a simple background for Flex apps. Add this property to the mx:Application to make the background white.
styleName="plain"

PHP: Error logging

Work with other languages has exposed me to new ways of logging errors and/or debugging code on web pages. I'm not sure how most php developers log errors or debug code so I can only guess it was similar to the way I would do it. By that I mean using echo in the middle of some HTML. It gets the job done, but it's kinda ugly.

I've since started using a cleaner method of logging errors. It's not as robust as a class, but it's better than throwing code out on a page. I've started using the error_log function wrapped in another function to control when it should output the error to a log.

function debug($allow_debug, $msg)
{
  if($allow_debug)
  {
    error_log($msg."\n", 3, '/path/to/phperror.log');
  }
}

When the function is used I pass a boolean that states wither I want the error passed out to the log. Typically I would set a variable at the top of the script and pass it into each instance of debug.

error_log takes three parameters. The first is the message that I want to pass out to the log. The important part on this input is the line return. That way each error starts on a new line. The second is the type of message I'm logging. The third is the location of the log file. Make sure it has the correct permissions so PHP can write to it.

You can view more information on error_log here.