Just like wp_options and wp_usermeta, wp_postmeta is used to save post related data. These data are generally called custom fields.

One can add custom field from post editor, as shown below:

For example, I have the inserted version in each post using the custom fields.

The structure of this table is as follows:

Indexes

In the table, the value is saved with meta_key and post id.

These fields can be handled using various functions like add_post_meta(),update_post_meta(),get_post_custom() etc. Please check this URL for more details:

http://codex.wordpress.org/Custom_Fields

Related posts:

1. Introduction to Wordpress Database: wp_usermeta
2. Introduction to Wordpress Database: wp_users
3. How to set expiration date for a post using custom fields?

Current Version : 2.9.2

Wordpress saves the user details in wp_users table. All the major details like user id, user_login, email address, password (In MD5) are saved in this table.

Below mentioned is the structure of this table:

Indexes

here, password is  MD5 encrypted.

We manually are not supposed to make any entry in this table. However, you can use this function in your template or plugin:

wp_insert_user()

This function requires an array of data to be inserted for the user. Please check more details here wp_insert_user().

Related posts:

1. Introduction to Wordpress Database: wp_usermeta
2. Introduction to Wordpress Database: wp_postmeta

Current Version: 2.9.2

In general, wordpress saves many user related data. It is difficult to save them in one column in wp_users. Hence Wordpress saves these data in wp_usermeta table. The structure of this table is mentioned below:

Indexes

In this table, we need to add following details:

user_id -> user_id of the user

meta_key -> a unique key for the user data

meta_value -> the actual data to be saved.

Wordpress provides following functions to manage this table:

get_usermeta($userid, $metakey )

$userid

(integer) (required) The ID of the user whose data should be retrieved.

Default: None

$metakey

(string) (required) The metakey value to be returned.

• 'metakey' The meta_key in the wp_usermeta table for the meta_value to be returned.

Default: None

update_usermeta( $userid, $metakey, $metavalue )

$userid

(integer) (required) The ID of the user whose data should be updated.

Default: None

$meta_key

(string) (required) The meta_key to be updated.

• 'meta_key' The meta_key in the wp_usermeta table for the meta_value to be updated.

Default: None

$meta_value

(string) (required) The new desired value of the meta_key, which must be different from any existing value.

Default: None

Returns: true if success, false if failed

delete_usermeta( $user_id, $meta_key, $meta_value )

$user_id

(integer) (required) The ID of the WordPress user

Default: None

$meta_key

(string) (required) The meta_key field value

Default: None

$meta_value

(string) (optional) The meta_value field value; if omitted, the key is deleted regardless of value

Default: None

Returns: true if success, false if failed

Related posts:

1. Introduction to Wordpress Database: wp_postmeta
2. Introduction to Wordpress Database: wp_users
3. Introduction to Wordpress Database: wp_options

Current Version: 2.9.2

Wp_options tables is used to store wordpress’s default settings, standard options etc. The structure of the table is as follows:

Indexes

This tables is used by wordpress to save  standard options, like blogurl, blog title, description, admin email address, rewrite rules etc.

This table is very useful for plugin and theme developers. A developer can store his own standard options in this table.

How to save data in this table:

To save data in this table, you need to use a unique key for your data, like “my_tracking_code”. This  key is saved in option_name field. The actual value is stored in option_value field.

Use the following function to add your own option:

add_option($name, $value = ”, $deprecated = ”, $autoload = ‘yes’);

Where,

$name

(string) (required) Name of the option to be added. Use underscores to separate words, and do not use uppercase—this is going to be placed into the database.

Default: None

$value

(string) (optional) Value for this option name. Limited to 2^32 bytes of data

Default: Empty

$deprecated

(string) (optional) Unused.

Default: Empty

$autoload

(string) (optional) Should this option be automatically loaded by the function wp_load_alloptions (puts options into object cache on each page load)? Valid values: yes or no.

Default: yes

Use the below mentioned function to update an existing option:

update_option( $option_name, $newvalue );

where,

option_name

(string) (required) Name of the option to update. Default: None

newvalue

(mixed) (required) The NEW value for this option name. This value can be a string, an array, an object or a serialized value.

Default: None

How to retrieve options value:

Use the below function to retrieve the option value:

get_option( $show, $default );

where,

$show

(string) (required) Name of the option to retrieve. Default: None

$default

(mixed) (optional) The default value to return if no value is returned (ie. the option is not in the database).

Default: false

This will return the option value in a variable.

A list of valid option reference is give by wordpress here:

Option_Reference

Related posts:

1. Introduction to Wordpress Database: wp_usermeta

In WordPress 2.9 whenever you upload an image, you can edit it using the edit image option.

The image editor contains several useful functions such as image cropping, image rotation and image flipping. In addition, you can also undo and redo your actions.
Post Trash Can

Wordpress 2.9 provides a very useful feature, called Post Trash Can. We all are very well aware of this feature and we use it for emails. However, you can use this feature for posts and comments from wordpress 2.9.

wp2-92

The new Trash feature completely replaces the old Delete functionality, when you click on the Trash link, the status of the post will be moved to “Trash”, and can be restored for a certain time limit, 30 days by default.

To view all the posts or page in Trash, just visit the Trash menu in the top of the Edit Posts or pages section.

You can also limit the number of days the trash can/should hold deleted posts by adding the following line to your wp-config.php:

define(’EMPTY_TRASH_DAYS’, 7);

Change the number 7 to the number of days you want to store deleted copies in the trash can.
Restoring Deleted Posts

If you deleted posts by mistake, you can always get it back by visiting the Trash menu and clicking on the restore link.
Disabling Trash Can Feature in WP 2.9

To disable trash feature, just add the following code to wp-config.php: define (’EMPTY_TRASH_DAYS’, 0);

Once you do that, you will see Delete Permanently option instead of Trash.

wp2-93
Embedding Videos and Images with oEmbed

oEmbed provides media providers with a way to provide additional information about a media used from their sites you are adding it from. For more information on this visit the oEmbed site.

In short, you can now embed videos directly into WordPress by providing the URL of the video, instead of having to add the entire embed code into it.

oEmbed support is enabled by default, you can disable it by visiting Settings -> Media.
Tackling Duplicate Content With rel=”canonical”

WordPress 2.9 adds a new tag to the page header which specifies the canonical path to the actual content. Using this tag is highly suggested if you want to tackle duplicate content.
Automatic Database Repairing

WordPress 2.9 introduces a new feature which can help you to automatically repair database problems. This can come in very handy as not many users usually manage their database or optimize them.

To setup Automatic DB repairs in WP 2.9, you will need to add a new constant to your wp-config.php file as follows:

define(’WP_ALLOW_REPAIR’, true);

Once you do that, WordPress will automatically repair the DB periodically

Related posts:

1. How to hide default menu of buddypress?
2. Check WordPress Plugin Compatibility before Upgrading/Installing

Today, we will see how we can assign an expiration date to a post, so the post will disappear after a particular date:

1)      Change the default loop in your index.php file as mentioned below:

2)      Now, when you add/edit a post, add a custom field expiration and assign the date as value(with the format mm/dd/yyyy 00:00:00). The post will disappear after that date from the home page.

Note that if you do not assign the custom field to a post, that post will not appear on your home page. This code needs some modification for the same.

Related posts:

1. How to Digg your wordpress post?

What is a Filter?

Filters are functions that WordPress passes data through, at certain points in execution, just before taking some action with the data (such as adding it to the database or sending it to the browser screen).

Filters passed data between database and browser. Most inputs and outputs in wordpress need to pass through at least one filter.

You can add your own filter to a plugin or theme for special purpose.

The basic steps to add your own filters to WordPress (described in more detail below) are:

1. Create the PHP function tha? filters the data.
2. Hook to the filter in WordPress, by calling add_filter()
3. Put your PHP function in a plugin file, and activate it.

We will have more look on how to create a filter in next articles.

No related posts.

2.8.6 fixes two security problems that can be exploited by registered, logged in users who have posting privileges.

Related posts:

1. Wordpress 2.8.3 Released!!
2. WordPress 2.8.4 Released
3. Wordpress 2.8.2 Released!

Now, wordpress users can check if the plugin is compatible with their wordpress version before installing the plugin itself. This feature is in testing (Beta) and has been implemented for several plugins in the wordpress directory.

You can check this for any version of wordpress and the plugin itself. Check the screen capture here:

Related posts:

1. How to get a wordpress.com API key?

What is podcasting?

Podcasting is distributing audio or video content via RSS 2.0, or Atom. Podcast clients such as iTunes, Juice, or CastPodder(linux) allow listeners to subscribe to your RSS/Atom feed and automatically download your content to their portable audio players as it becomes available.

Podcast in Wordpress: (wordpress.com)

Create audio or video that you want to share (usually MP3 or MP4)
Upload the file to a server
Link to the file in a post in your weblog
Wordpress automatically Includes a link to the file in your RSS/Atom feed
Listeners

Related posts:

1. New Features in Wordpress 2.9: A brief Introduction
2. An Introduction to Feed and Reader
3. Increase RSS Update Time Limit | Wordpress 2.8.3