WordPress/wp-includes/wp-db.php
ryan e8b6fe7347 Trim trailing whitespace
git-svn-id: http://svn.automattic.com/wordpress/trunk@10810 1a063a9b-81f0-0310-95a4-ce76da25c4cd
2009-03-18 02:43:45 +00:00

1072 lines
27 KiB
PHP

<?php
/**
* WordPress DB Class
*
* Original code from {@link http://php.justinvincent.com Justin Vincent (justin@visunet.ie)}
*
* @package WordPress
* @subpackage Database
* @since 0.71
*/
/**
* @since 0.71
*/
define('EZSQL_VERSION', 'WP1.25');
/**
* @since 0.71
*/
define('OBJECT', 'OBJECT', true);
/**
* @since {@internal Version Unknown}}
*/
define('OBJECT_K', 'OBJECT_K', false);
/**
* @since 0.71
*/
define('ARRAY_A', 'ARRAY_A', false);
/**
* @since 0.71
*/
define('ARRAY_N', 'ARRAY_N', false);
/**
* WordPress Database Access Abstraction Object
*
* It is possible to replace this class with your own
* by setting the $wpdb global variable in wp-content/db.php
* file with your class. You can name it wpdb also, since
* this file will not be included, if the other file is
* available.
*
* @link http://codex.wordpress.org/Function_Reference/wpdb_Class
*
* @package WordPress
* @subpackage Database
* @since 0.71
* @final
*/
class wpdb {
/**
* Whether to show SQL/DB errors
*
* @since 0.71
* @access private
* @var bool
*/
var $show_errors = false;
/**
* Whether to suppress errors during the DB bootstrapping.
*
* @access private
* @since {@internal Version Unknown}}
* @var bool
*/
var $suppress_errors = false;
/**
* The last error during query.
*
* @since {@internal Version Unknown}}
* @var string
*/
var $last_error = '';
/**
* Amount of queries made
*
* @since 1.2.0
* @access private
* @var int
*/
var $num_queries = 0;
/**
* Saved result of the last query made
*
* @since 1.2.0
* @access private
* @var array
*/
var $last_query;
/**
* Saved info on the table column
*
* @since 1.2.0
* @access private
* @var array
*/
var $col_info;
/**
* Saved queries that were executed
*
* @since 1.5.0
* @access private
* @var array
*/
var $queries;
/**
* WordPress table prefix
*
* You can set this to have multiple WordPress installations
* in a single database. The second reason is for possible
* security precautions.
*
* @since 0.71
* @access private
* @var string
*/
var $prefix = '';
/**
* Whether the database queries are ready to start executing.
*
* @since 2.5.0
* @access private
* @var bool
*/
var $ready = false;
/**
* WordPress Posts table
*
* @since 1.5.0
* @access public
* @var string
*/
var $posts;
/**
* WordPress Users table
*
* @since 1.5.0
* @access public
* @var string
*/
var $users;
/**
* WordPress Categories table
*
* @since 1.5.0
* @access public
* @var string
*/
var $categories;
/**
* WordPress Post to Category table
*
* @since 1.5.0
* @access public
* @var string
*/
var $post2cat;
/**
* WordPress Comments table
*
* @since 1.5.0
* @access public
* @var string
*/
var $comments;
/**
* WordPress Links table
*
* @since 1.5.0
* @access public
* @var string
*/
var $links;
/**
* WordPress Options table
*
* @since 1.5.0
* @access public
* @var string
*/
var $options;
/**
* WordPress Post Metadata table
*
* @since {@internal Version Unknown}}
* @access public
* @var string
*/
var $postmeta;
/**
* WordPress User Metadata table
*
* @since 2.3.0
* @access public
* @var string
*/
var $usermeta;
/**
* WordPress Terms table
*
* @since 2.3.0
* @access public
* @var string
*/
var $terms;
/**
* WordPress Term Taxonomy table
*
* @since 2.3.0
* @access public
* @var string
*/
var $term_taxonomy;
/**
* WordPress Term Relationships table
*
* @since 2.3.0
* @access public
* @var string
*/
var $term_relationships;
/**
* List of WordPress tables
*
* @since {@internal Version Unknown}}
* @access private
* @var array
*/
var $tables = array('users', 'usermeta', 'posts', 'categories', 'post2cat', 'comments', 'links', 'link2cat', 'options',
'postmeta', 'terms', 'term_taxonomy', 'term_relationships');
/**
* Database table columns charset
*
* @since 2.2.0
* @access public
* @var string
*/
var $charset;
/**
* Database table columns collate
*
* @since 2.2.0
* @access public
* @var string
*/
var $collate;
/**
* Whether to use mysql_real_escape_string
*
* @since 2.8.0
* @access public
* @var bool
*/
var $real_escape = false;
/**
* Connects to the database server and selects a database
*
* PHP4 compatibility layer for calling the PHP5 constructor.
*
* @uses wpdb::__construct() Passes parameters and returns result
* @since 0.71
*
* @param string $dbuser MySQL database user
* @param string $dbpassword MySQL database password
* @param string $dbname MySQL database name
* @param string $dbhost MySQL database host
*/
function wpdb($dbuser, $dbpassword, $dbname, $dbhost) {
return $this->__construct($dbuser, $dbpassword, $dbname, $dbhost);
}
/**
* Connects to the database server and selects a database
*
* PHP5 style constructor for compatibility with PHP5. Does
* the actual setting up of the class properties and connection
* to the database.
*
* @since 2.0.8
*
* @param string $dbuser MySQL database user
* @param string $dbpassword MySQL database password
* @param string $dbname MySQL database name
* @param string $dbhost MySQL database host
*/
function __construct($dbuser, $dbpassword, $dbname, $dbhost) {
register_shutdown_function(array(&$this, "__destruct"));
if ( defined('WP_DEBUG') and WP_DEBUG == true )
$this->show_errors();
if ( defined('DB_CHARSET') )
$this->charset = DB_CHARSET;
if ( defined('DB_COLLATE') )
$this->collate = DB_COLLATE;
$this->dbh = @mysql_connect($dbhost, $dbuser, $dbpassword, true);
if (!$this->dbh) {
$this->bail(sprintf(/*WP_I18N_DB_CONN_ERROR*/"
<h1>Error establishing a database connection</h1>
<p>This either means that the username and password information in your <code>wp-config.php</code> file is incorrect or we can't contact the database server at <code>%s</code>. This could mean your host's database server is down.</p>
<ul>
<li>Are you sure you have the correct username and password?</li>
<li>Are you sure that you have typed the correct hostname?</li>
<li>Are you sure that the database server is running?</li>
</ul>
<p>If you're unsure what these terms mean you should probably contact your host. If you still need help you can always visit the <a href='http://wordpress.org/support/'>WordPress Support Forums</a>.</p>
"/*/WP_I18N_DB_CONN_ERROR*/, $dbhost));
return;
}
$this->ready = true;
if ( $this->has_cap( 'collation' ) ) {
if ( !empty($this->charset) ) {
if ( function_exists('mysql_set_charset') ) {
mysql_set_charset($this->charset, $this->dbh);
$this->real_escape = true;
} else {
$collation_query = "SET NAMES '{$this->charset}'";
if ( !empty($this->collate) )
$collation_query .= " COLLATE '{$this->collate}'";
$this->query($collation_query);
}
}
}
$this->select($dbname);
}
/**
* PHP5 style destructor and will run when database object is destroyed.
*
* @since 2.0.8
*
* @return bool Always true
*/
function __destruct() {
return true;
}
/**
* Sets the table prefix for the WordPress tables.
*
* Also allows for the CUSTOM_USER_TABLE and CUSTOM_USER_META_TABLE to
* override the WordPress users and usersmeta tables.
*
* @since 2.5.0
*
* @param string $prefix Alphanumeric name for the new prefix.
* @return string Old prefix
*/
function set_prefix($prefix) {
if ( preg_match('|[^a-z0-9_]|i', $prefix) )
return new WP_Error('invalid_db_prefix', /*WP_I18N_DB_BAD_PREFIX*/'Invalid database prefix'/*/WP_I18N_DB_BAD_PREFIX*/);
$old_prefix = $this->prefix;
$this->prefix = $prefix;
foreach ( (array) $this->tables as $table )
$this->$table = $this->prefix . $table;
if ( defined('CUSTOM_USER_TABLE') )
$this->users = CUSTOM_USER_TABLE;
if ( defined('CUSTOM_USER_META_TABLE') )
$this->usermeta = CUSTOM_USER_META_TABLE;
return $old_prefix;
}
/**
* Selects a database using the current database connection.
*
* The database name will be changed based on the current database
* connection. On failure, the execution will bail and display an DB error.
*
* @since 0.71
*
* @param string $db MySQL database name
* @return null Always null.
*/
function select($db) {
if (!@mysql_select_db($db, $this->dbh)) {
$this->ready = false;
$this->bail(sprintf(/*WP_I18N_DB_SELECT_DB*/'
<h1>Can&#8217;t select database</h1>
<p>We were able to connect to the database server (which means your username and password is okay) but not able to select the <code>%1$s</code> database.</p>
<ul>
<li>Are you sure it exists?</li>
<li>Does the user <code>%2$s</code> have permission to use the <code>%1$s</code> database?</li>
<li>On some systems the name of your database is prefixed with your username, so it would be like <code>username_%1$s</code>. Could that be the problem?</li>
</ul>
<p>If you don\'t know how to setup a database you should <strong>contact your host</strong>. If all else fails you may find help at the <a href="http://wordpress.org/support/">WordPress Support Forums</a>.</p>'/*/WP_I18N_DB_SELECT_DB*/, $db, DB_USER));
return;
}
}
function _weak_escape($string) {
return addslashes($string);
}
function _real_escape($string) {
if ( $this->dbh && $this->real_escape )
return mysql_real_escape_string( $string, $this->dbh );
else
return addslashes( $string );
}
function _escape($data) {
if ( is_array($data) ) {
foreach ( (array) $data as $k => $v ) {
if ( is_array($v) )
$data[$k] = $this->_escape( $v );
else
$data[$k] = $this->_real_escape( $v );
}
} else {
$data = $this->_real_escape( $data );
}
return $data;
}
/**
* Escapes content for insertion into the database using addslashes(), for security
*
* @since 0.71
*
* @param string|array $data
* @return string query safe string
*/
function escape($data) {
if ( is_array($data) ) {
foreach ( (array) $data as $k => $v ) {
if ( is_array($v) )
$data[$k] = $this->escape( $v );
else
$data[$k] = $this->_weak_escape( $v );
}
} else {
$data = $this->_weak_escape( $data );
}
return $data;
}
/**
* Escapes content by reference for insertion into the database, for security
*
* @since 2.3.0
*
* @param string $s
*/
function escape_by_ref(&$string) {
$string = $this->_real_escape( $string );
}
/**
* Prepares a SQL query for safe use, using sprintf() syntax.
*
* @link http://php.net/sprintf See for syntax to use for query string.
* @since 2.3.0
*
* @param null|string $args If string, first parameter must be query statement
* @param mixed $args,... If additional parameters, they will be set inserted into the query.
* @return null|string Sanitized query string
*/
function prepare($args=null) {
if ( is_null( $args ) )
return;
$args = func_get_args();
$query = array_shift($args);
// If args were passed as an array, move them up
if ( isset($args[0]) && is_array($args[0]) )
$args = $args[0];
$query = str_replace("'%s'", '%s', $query); // in case someone mistakenly already singlequoted it
$query = str_replace('"%s"', '%s', $query); // doublequote unquoting
$query = str_replace('%s', "'%s'", $query); // quote the strings
array_walk($args, array(&$this, 'escape_by_ref'));
return @vsprintf($query, $args);
}
/**
* Print SQL/DB error.
*
* @since 0.71
* @global array $EZSQL_ERROR Stores error information of query and error string
*
* @param string $str The error to display
* @return bool False if the showing of errors is disabled.
*/
function print_error($str = '') {
global $EZSQL_ERROR;
if (!$str) $str = mysql_error($this->dbh);
$EZSQL_ERROR[] = array ('query' => $this->last_query, 'error_str' => $str);
if ( $this->suppress_errors )
return false;
if ( $caller = $this->get_caller() )
$error_str = sprintf(/*WP_I18N_DB_QUERY_ERROR_FULL*/'WordPress database error %1$s for query %2$s made by %3$s'/*/WP_I18N_DB_QUERY_ERROR_FULL*/, $str, $this->last_query, $caller);
else
$error_str = sprintf(/*WP_I18N_DB_QUERY_ERROR*/'WordPress database error %1$s for query %2$s'/*/WP_I18N_DB_QUERY_ERROR*/, $str, $this->last_query);
$log_error = true;
if ( ! function_exists('error_log') )
$log_error = false;
$log_file = @ini_get('error_log');
if ( !empty($log_file) && ('syslog' != $log_file) && !@is_writable($log_file) )
$log_error = false;
if ( $log_error )
@error_log($error_str, 0);
// Is error output turned on or not..
if ( !$this->show_errors )
return false;
$str = htmlspecialchars($str, ENT_QUOTES);
$query = htmlspecialchars($this->last_query, ENT_QUOTES);
// If there is an error then take note of it
print "<div id='error'>
<p class='wpdberror'><strong>WordPress database error:</strong> [$str]<br />
<code>$query</code></p>
</div>";
}
/**
* Enables showing of database errors.
*
* This function should be used only to enable showing of errors.
* wpdb::hide_errors() should be used instead for hiding of errors. However,
* this function can be used to enable and disable showing of database
* errors.
*
* @since 0.71
*
* @param bool $show Whether to show or hide errors
* @return bool Old value for showing errors.
*/
function show_errors( $show = true ) {
$errors = $this->show_errors;
$this->show_errors = $show;
return $errors;
}
/**
* Disables showing of database errors.
*
* @since 0.71
*
* @return bool Whether showing of errors was active or not
*/
function hide_errors() {
$show = $this->show_errors;
$this->show_errors = false;
return $show;
}
/**
* Whether to suppress database errors.
*
* @param unknown_type $suppress
* @return unknown
*/
function suppress_errors( $suppress = true ) {
$errors = $this->suppress_errors;
$this->suppress_errors = $suppress;
return $errors;
}
/**
* Kill cached query results.
*
* @since 0.71
*/
function flush() {
$this->last_result = array();
$this->col_info = null;
$this->last_query = null;
}
/**
* Perform a MySQL database query, using current database connection.
*
* More information can be found on the codex page.
*
* @since 0.71
*
* @param string $query
* @return unknown
*/
function query($query) {
if ( ! $this->ready )
return false;
// filter the query, if filters are available
// NOTE: some queries are made before the plugins have been loaded, and thus cannot be filtered with this method
if ( function_exists('apply_filters') )
$query = apply_filters('query', $query);
// initialise return
$return_val = 0;
$this->flush();
// Log how the function was called
$this->func_call = "\$db->query(\"$query\")";
// Keep track of the last query for debug..
$this->last_query = $query;
// Perform the query via std mysql_query function..
if ( defined('SAVEQUERIES') && SAVEQUERIES )
$this->timer_start();
$this->result = @mysql_query($query, $this->dbh);
++$this->num_queries;
if ( defined('SAVEQUERIES') && SAVEQUERIES )
$this->queries[] = array( $query, $this->timer_stop(), $this->get_caller() );
// If there is an error then take note of it..
if ( $this->last_error = mysql_error($this->dbh) ) {
$this->print_error();
return false;
}
if ( preg_match("/^\\s*(insert|delete|update|replace|alter) /i",$query) ) {
$this->rows_affected = mysql_affected_rows($this->dbh);
// Take note of the insert_id
if ( preg_match("/^\\s*(insert|replace) /i",$query) ) {
$this->insert_id = mysql_insert_id($this->dbh);
}
// Return number of rows affected
$return_val = $this->rows_affected;
} else {
$i = 0;
while ($i < @mysql_num_fields($this->result)) {
$this->col_info[$i] = @mysql_fetch_field($this->result);
$i++;
}
$num_rows = 0;
while ( $row = @mysql_fetch_object($this->result) ) {
$this->last_result[$num_rows] = $row;
$num_rows++;
}
@mysql_free_result($this->result);
// Log number of rows the query returned
$this->num_rows = $num_rows;
// Return number of rows selected
$return_val = $this->num_rows;
}
return $return_val;
}
/**
* Insert an array of data into a table.
*
* @since 2.5.0
*
* @param string $table WARNING: not sanitized!
* @param array $data Should not already be SQL-escaped
* @param array|string $format The format of the field values.
* @return mixed Results of $this->query()
*/
function insert($table, $data, $format = null) {
global $db_field_types;
$formats = $format = (array) $format;
$fields = array_keys($data);
$formatted_fields = array();
foreach ( $fields as $field ) {
if ( !empty($format) )
$form = ( $form = array_shift($formats) ) ? $form : $format[0];
elseif ( isset($db_field_types[$field]) )
$form = $db_field_types[$field];
else
$form = '%s';
$formatted_fields[] = $form;
}
$sql = "INSERT INTO $table (`" . implode( '`,`', $fields ) . "`) VALUES ('" . implode( "','", $formatted_fields ) . "')";
return $this->query( $this->prepare( $sql, $data) );
}
/**
* Update a row in the table with an array of data.
*
* @since 2.5.0
*
* @param string $table WARNING: not sanitized!
* @param array $data Should not already be SQL-escaped
* @param array $where A named array of WHERE column => value relationships. Multiple member pairs will be joined with ANDs. WARNING: the column names are not currently sanitized!
* @param array|string $format The format of the field values.
* @param array|string $where_format The format of the where field values.
* @return mixed Results of $this->query()
*/
function update($table, $data, $where, $format = null, $where_format = null) {
global $db_field_types;
if ( !is_array( $where ) )
return false;
$formats = $format = (array) $format;
$bits = $wheres = array();
foreach ( (array) array_keys($data) as $field ) {
if ( !empty($format) )
$form = ( $form = array_shift($formats) ) ? $form : $format[0];
elseif ( isset($db_field_types[$field]) )
$form = $db_field_types[$field];
else
$form = '%s';
$bits[] = "`$field` = {$form}";
}
$where_formats = $where_format = (array) $where_format;
foreach ( (array) array_keys($where) as $field ) {
if ( !empty($where_format) )
$form = ( $form = array_shift($where_formats) ) ? $form : $where_format[0];
elseif ( isset($db_field_types[$field]) )
$form = $db_field_types[$field];
else
$form = '%s';
$wheres[] = "$field = {$form}";
}
$sql = "UPDATE $table SET " . implode( ', ', $bits ) . ' WHERE ' . implode( ' AND ', $wheres );
return $this->query( $this->prepare( $sql, array_merge(array_values($data), array_values($where))) );
}
/**
* Retrieve one variable from the database.
*
* This combines the functionality of wpdb::get_row() and wpdb::get_col(),
* so both the column and row can be picked.
*
* It is possible to use this function without executing more queries. If
* you already made a query, you can set the $query to 'null' value and just
* retrieve either the column and row of the last query result.
*
* @since 0.71
*
* @param string $query Can be null as well, for caching
* @param int $x Column num to return
* @param int $y Row num to return
* @return mixed Database query results
*/
function get_var($query=null, $x = 0, $y = 0) {
$this->func_call = "\$db->get_var(\"$query\",$x,$y)";
if ( $query )
$this->query($query);
// Extract var out of cached results based x,y vals
if ( !empty( $this->last_result[$y] ) ) {
$values = array_values(get_object_vars($this->last_result[$y]));
}
// If there is a value return it else return null
return (isset($values[$x]) && $values[$x]!=='') ? $values[$x] : null;
}
/**
* Retrieve one row from the database.
*
* @since 0.71
*
* @param string $query SQL query
* @param string $output ARRAY_A | ARRAY_N | OBJECT
* @param int $y Row num to return
* @return mixed Database query results
*/
function get_row($query = null, $output = OBJECT, $y = 0) {
$this->func_call = "\$db->get_row(\"$query\",$output,$y)";
if ( $query )
$this->query($query);
else
return null;
if ( !isset($this->last_result[$y]) )
return null;
if ( $output == OBJECT ) {
return $this->last_result[$y] ? $this->last_result[$y] : null;
} elseif ( $output == ARRAY_A ) {
return $this->last_result[$y] ? get_object_vars($this->last_result[$y]) : null;
} elseif ( $output == ARRAY_N ) {
return $this->last_result[$y] ? array_values(get_object_vars($this->last_result[$y])) : null;
} else {
$this->print_error(/*WP_I18N_DB_GETROW_ERROR*/" \$db->get_row(string query, output type, int offset) -- Output type must be one of: OBJECT, ARRAY_A, ARRAY_N"/*/WP_I18N_DB_GETROW_ERROR*/);
}
}
/**
* Retrieve one column from the database.
*
* @since 0.71
*
* @param string $query Can be null as well, for caching
* @param int $x Col num to return. Starts from 0.
* @return array Column results
*/
function get_col($query = null , $x = 0) {
if ( $query )
$this->query($query);
$new_array = array();
// Extract the column values
for ( $i=0; $i < count($this->last_result); $i++ ) {
$new_array[$i] = $this->get_var(null, $x, $i);
}
return $new_array;
}
/**
* Retrieve an entire result set from the database.
*
* @since 0.71
*
* @param string|null $query Can also be null to pull from the cache
* @param string $output ARRAY_A | ARRAY_N | OBJECT_K | OBJECT
* @return mixed Database query results
*/
function get_results($query = null, $output = OBJECT) {
$this->func_call = "\$db->get_results(\"$query\", $output)";
if ( $query )
$this->query($query);
else
return null;
if ( $output == OBJECT ) {
// Return an integer-keyed array of row objects
return $this->last_result;
} elseif ( $output == OBJECT_K ) {
// Return an array of row objects with keys from column 1
// (Duplicates are discarded)
foreach ( $this->last_result as $row ) {
$key = array_shift( get_object_vars( $row ) );
if ( !isset( $new_array[ $key ] ) )
$new_array[ $key ] = $row;
}
return $new_array;
} elseif ( $output == ARRAY_A || $output == ARRAY_N ) {
// Return an integer-keyed array of...
if ( $this->last_result ) {
$i = 0;
foreach( (array) $this->last_result as $row ) {
if ( $output == ARRAY_N ) {
// ...integer-keyed row arrays
$new_array[$i] = array_values( get_object_vars( $row ) );
} else {
// ...column name-keyed row arrays
$new_array[$i] = get_object_vars( $row );
}
++$i;
}
return $new_array;
}
}
}
/**
* Retrieve column metadata from the last query.
*
* @since 0.71
*
* @param string $info_type one of name, table, def, max_length, not_null, primary_key, multiple_key, unique_key, numeric, blob, type, unsigned, zerofill
* @param int $col_offset 0: col name. 1: which table the col's in. 2: col's max length. 3: if the col is numeric. 4: col's type
* @return mixed Column Results
*/
function get_col_info($info_type = 'name', $col_offset = -1) {
if ( $this->col_info ) {
if ( $col_offset == -1 ) {
$i = 0;
foreach( (array) $this->col_info as $col ) {
$new_array[$i] = $col->{$info_type};
$i++;
}
return $new_array;
} else {
return $this->col_info[$col_offset]->{$info_type};
}
}
}
/**
* Starts the timer, for debugging purposes.
*
* @since 1.5.0
*
* @return bool Always returns true
*/
function timer_start() {
$mtime = microtime();
$mtime = explode(' ', $mtime);
$this->time_start = $mtime[1] + $mtime[0];
return true;
}
/**
* Stops the debugging timer.
*
* @since 1.5.0
*
* @return int Total time spent on the query, in milliseconds
*/
function timer_stop() {
$mtime = microtime();
$mtime = explode(' ', $mtime);
$time_end = $mtime[1] + $mtime[0];
$time_total = $time_end - $this->time_start;
return $time_total;
}
/**
* Wraps fatal errors in a nice header and footer and dies.
*
* @since 1.5.0
*
* @param string $message
* @return unknown
*/
function bail($message) {
if ( !$this->show_errors ) {
if ( class_exists('WP_Error') )
$this->error = new WP_Error('500', $message);
else
$this->error = $message;
return false;
}
wp_die($message);
}
/**
* Whether or not MySQL database is minimal required version.
*
* @since 2.5.0
* @uses $wp_version
*
* @return WP_Error
*/
function check_database_version()
{
global $wp_version;
// Make sure the server has MySQL 4.0
if ( version_compare($this->db_version(), '4.0.0', '<') )
return new WP_Error('database_version',sprintf(__('<strong>ERROR</strong>: WordPress %s requires MySQL 4.0.0 or higher'), $wp_version));
}
/**
* Whether of not the database version supports collation.
*
* Called when WordPress is generating the table scheme.
*
* @since 2.5.0
*
* @return bool True if collation is supported, false if version does not
*/
function supports_collation()
{
return $this->has_cap( 'collation' );
}
/**
* Generic function to determine if a database supports a particular feature
* @param string $db_cap the feature
* @param false|string|resource $dbh_or_table the databaese (the current database, the database housing the specified table, or the database of the mysql resource)
* @return bool
*/
function has_cap( $db_cap ) {
$version = $this->db_version();
switch ( strtolower( $db_cap ) ) :
case 'collation' : // @since 2.5.0
case 'group_concat' : // @since 2.7
case 'subqueries' : // @since 2.7
return version_compare($version, '4.1', '>=');
break;
endswitch;
return false;
}
/**
* Retrieve the name of the function that called wpdb.
*
* Requires PHP 4.3 and searches up the list of functions until it reaches
* the one that would most logically had called this method.
*
* @since 2.5.0
*
* @return string The name of the calling function
*/
function get_caller() {
// requires PHP 4.3+
if ( !is_callable('debug_backtrace') )
return '';
$bt = debug_backtrace();
$caller = array();
$bt = array_reverse( $bt );
foreach ( (array) $bt as $call ) {
if ( @$call['class'] == __CLASS__ )
continue;
$function = $call['function'];
if ( isset( $call['class'] ) )
$function = $call['class'] . "->$function";
$caller[] = $function;
}
$caller = join( ', ', $caller );
return $caller;
}
/**
* The database version number
* @return false|string false on failure, version number on success
*/
function db_version() {
return preg_replace('/[^0-9.].*/', '', mysql_get_server_info( $this->dbh ));
}
}
if ( ! isset($wpdb) ) {
/**
* WordPress Database Object, if it isn't set already in wp-content/db.php
* @global object $wpdb Creates a new wpdb object based on wp-config.php Constants for the database
* @since 0.71
*/
$wpdb = new wpdb(DB_USER, DB_PASSWORD, DB_NAME, DB_HOST);
}
?>