WordPress CRUD

create.php

<?php
// Create a new record in a table

global $wpdb;

// data to be added
$data = array(
	'post_title' => __('This is a test'),
	'post_content' => __('This is really long text'),
	'post_status' => __('draft')
);

// Data format
$data_format = array(
	'%s',	// post_title
	'%s',	// post_content
	'%s'	// post_status
);
$wpdb->insert('wp_posts', $data, $data_format);
?>

delete.php

<?php
// Delete a record from a table

global $wpdb;
$where = array(
	'id' => 5
);
$where_format = array(
	'%d'	// id
);
$wpdb->delete('wp_posts', $where, $where_format)
?>

query.php

<?php
// Run sql queries manually

global $wpdb;

// wpdb::prepare() requires 2 parameters. More info: http://make.wordpress.org/core/2012/12/12/php-warning-missing-argument-2-for-wpdb-prepare/
$sql = $wpdb->prepare("SELECT * FROM " . $wpdb->posts . "WHERE post_title = %s", $_GET['title']);
$results = $wpdb->query($sql);
?>

read.php

<?php
// Reading data from the database

global $wpdb;

// wpdb::get_results()
$sql = "SELECT * FROM " . $wpdb->posts;
$results = $wpdb->get_results($sql);

// wpdb::get_row()
$sql2 = "SELECT * FROM " . $wpdb->posts ." WHERE post_title = 'This is a test'";
$results2 = $wpdb->get_row($sql2);

// wpdb::get_col()
$sql3 = "SELECT post_status FROM " . $wpdb->posts;
$results3 = $wpdb->get_col($sql3);

// wpdb::get_var()
$sql4 = "SELECT post_status FROM " . $wpdb->posts . " WHERE post_title = 'This is a test'";
$results4 = $wpdb->get_var($sql4);
?>

update.php

<?php
// Update a row in a table

global $wpdb;

// What values are we changing
$data = array(
	'post_title' => __('This is another test'),
	'post_content' => __('This is more text than previously entered'),
	'post_status' => __('publish')
);

// What format is the data
$data_format = array(
	'%s',	// post_title
	'%s',	// post_content
	'%s'	// post_status
);

// What are we searching by
$where = array(
	'post_title' => __('This is a test')
);

// What format is the search data in
$where_format = array(
	'%s'	
);

// Run the query
$wpdb->update('wp_posts', $data, $where, $data_format, $where_format);
?>