MySQL provides a very simple method to select rows in random order. It uses the ORDER BY RAND()statement. If you will be used theORDER BY RAND() statement, MySQL will create a temporary table with all results, then will be assigned a random index to each row and finally will return the random rows! This makes the ORDER BY RAND() quite slow. In fact, some developer prefers alternative techniques, such as PHP random functions or special SQL select.

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When you would like to show a page only for a specified user or you wish to create a maintenance page, you may use this simple script:

 

With Xcode 4 you can develop applications for iPad and iPhone. Also, you can choose a different iOS target. Currently, the last release of iOS is 4.3 and when you will create a new project you will see:

Now, the rootViewController property has been added with iOS 4. This mean that when we going to test the application in iOS 3.2 environment we will get a CRASH! Instead to check the iOS version, we can use a feature of Obejctve-C in order to check if a property exists:

As usual, please don’t hesitate to leave any questions or comments in the feed below, and I’ll aim to respond to each of them.

The last version of WordPress provides a new toolbar in frontend view when you are logged in. To disable this feature you can add the following code in the functions.php file in your active theme:

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Apple suggests to use an instance of NSFileManager class and avoid the static class method defaultManagerbecause it will return a singleton instance: no thread safe:

In Mac OS X v.10.5 and later you should consider using [[NSFileManager alloc] init] rather than the singleton method defaultManager. Using [[NSFileManager alloc] init] instead, the resulting NSFileManager instance is thread safe.

For example:

If you  would like to avoid to set the background image of main view controller through Interface Builder, you can use a different way and delete the UIImageview object from Interface Builder:

You may use viewDidLoad as well but viewWillAppear avoid some flickering. With Xcode 3.2.5 is not possible to use the pattern yet.

How to check if an element DOM exists

Be careful when you wish if an element DOM exists. If you use:

This method doesn’t work because jQuery will return an [Object object] even if the element doesn’t exist. We may use a couple of methods to be sure that an element exists: Read More

You remember the post How to get a page/post content, don’t you? Then, we may get the page/post content by:

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We have to use a little trick! In other words, we will remove the meta box and then we will add a new one again:

 

How to merge one or more images

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