diff includes/database.inc @ 1:c1f4ac30525a 6.0

Drupal 6.0
author Franck Deroche <webmaster@defr.org>
date Tue, 23 Dec 2008 14:28:28 +0100
parents
children fff6d4c8c043
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/includes/database.inc	Tue Dec 23 14:28:28 2008 +0100
@@ -0,0 +1,583 @@
+<?php
+// $Id: database.inc,v 1.92.2.1 2008/02/08 22:44:59 goba Exp $
+
+/**
+ * @file
+ * Wrapper for database interface code.
+ */
+
+/**
+ * A hash value to check when outputting database errors, md5('DB_ERROR').
+ *
+ * @see drupal_error_handler()
+ */
+define('DB_ERROR', 'a515ac9c2796ca0e23adbe92c68fc9fc');
+
+/**
+ * @defgroup database Database abstraction layer
+ * @{
+ * Allow the use of different database servers using the same code base.
+ *
+ * Drupal provides a slim database abstraction layer to provide developers with
+ * the ability to support multiple database servers easily. The intent of this
+ * layer is to preserve the syntax and power of SQL as much as possible, while
+ * letting Drupal control the pieces of queries that need to be written
+ * differently for different servers and provide basic security checks.
+ *
+ * Most Drupal database queries are performed by a call to db_query() or
+ * db_query_range(). Module authors should also consider using pager_query() for
+ * queries that return results that need to be presented on multiple pages, and
+ * tablesort_sql() for generating appropriate queries for sortable tables.
+ *
+ * For example, one might wish to return a list of the most recent 10 nodes
+ * authored by a given user. Instead of directly issuing the SQL query
+ * @code
+ *   SELECT n.title, n.body, n.created FROM node n WHERE n.uid = $uid LIMIT 0, 10;
+ * @endcode
+ * one would instead call the Drupal functions:
+ * @code
+ *   $result = db_query_range('SELECT n.title, n.body, n.created
+ *     FROM {node} n WHERE n.uid = %d', $uid, 0, 10);
+ *   while ($node = db_fetch_object($result)) {
+ *     // Perform operations on $node->body, etc. here.
+ *   }
+ * @endcode
+ * Curly braces are used around "node" to provide table prefixing via
+ * db_prefix_tables(). The explicit use of a user ID is pulled out into an
+ * argument passed to db_query() so that SQL injection attacks from user input
+ * can be caught and nullified. The LIMIT syntax varies between database servers,
+ * so that is abstracted into db_query_range() arguments. Finally, note the
+ * common pattern of iterating over the result set using db_fetch_object().
+ */
+
+/**
+ * Perform an SQL query and return success or failure.
+ *
+ * @param $sql
+ *   A string containing a complete SQL query.  %-substitution
+ *   parameters are not supported.
+ * @return
+ *   An array containing the keys:
+ *      success: a boolean indicating whether the query succeeded
+ *      query: the SQL query executed, passed through check_plain()
+ */
+function update_sql($sql) {
+  $result = db_query($sql, true);
+  return array('success' => $result !== FALSE, 'query' => check_plain($sql));
+}
+
+/**
+ * Append a database prefix to all tables in a query.
+ *
+ * Queries sent to Drupal should wrap all table names in curly brackets. This
+ * function searches for this syntax and adds Drupal's table prefix to all
+ * tables, allowing Drupal to coexist with other systems in the same database if
+ * necessary.
+ *
+ * @param $sql
+ *   A string containing a partial or entire SQL query.
+ * @return
+ *   The properly-prefixed string.
+ */
+function db_prefix_tables($sql) {
+  global $db_prefix;
+
+  if (is_array($db_prefix)) {
+    if (array_key_exists('default', $db_prefix)) {
+      $tmp = $db_prefix;
+      unset($tmp['default']);
+      foreach ($tmp as $key => $val) {
+        $sql = strtr($sql, array('{'. $key .'}' => $val . $key));
+      }
+      return strtr($sql, array('{' => $db_prefix['default'], '}' => ''));
+    }
+    else {
+      foreach ($db_prefix as $key => $val) {
+        $sql = strtr($sql, array('{'. $key .'}' => $val . $key));
+      }
+      return strtr($sql, array('{' => '', '}' => ''));
+    }
+  }
+  else {
+    return strtr($sql, array('{' => $db_prefix, '}' => ''));
+  }
+}
+
+/**
+ * Activate a database for future queries.
+ *
+ * If it is necessary to use external databases in a project, this function can
+ * be used to change where database queries are sent. If the database has not
+ * yet been used, it is initialized using the URL specified for that name in
+ * Drupal's configuration file. If this name is not defined, a duplicate of the
+ * default connection is made instead.
+ *
+ * Be sure to change the connection back to the default when done with custom
+ * code.
+ *
+ * @param $name
+ *   The name assigned to the newly active database connection. If omitted, the
+ *   default connection will be made active.
+ *
+ * @return the name of the previously active database or FALSE if non was found.
+ */
+function db_set_active($name = 'default') {
+  global $db_url, $db_type, $active_db;
+  static $db_conns, $active_name = FALSE;
+
+  if (empty($db_url)) {
+    include_once 'includes/install.inc';
+    install_goto('install.php');
+  }
+
+  if (!isset($db_conns[$name])) {
+    // Initiate a new connection, using the named DB URL specified.
+    if (is_array($db_url)) {
+      $connect_url = array_key_exists($name, $db_url) ? $db_url[$name] : $db_url['default'];
+    }
+    else {
+      $connect_url = $db_url;
+    }
+
+    $db_type = substr($connect_url, 0, strpos($connect_url, '://'));
+    $handler = "./includes/database.$db_type.inc";
+
+    if (is_file($handler)) {
+      include_once $handler;
+    }
+    else {
+      _db_error_page("The database type '". $db_type ."' is unsupported. Please use either 'mysql' or 'mysqli' for MySQL, or 'pgsql' for PostgreSQL databases.");
+    }
+
+    $db_conns[$name] = db_connect($connect_url);
+  }
+
+  $previous_name = $active_name;
+  // Set the active connection.
+  $active_name = $name;
+  $active_db = $db_conns[$name];
+
+  return $previous_name;
+}
+
+/**
+ * Helper function to show fatal database errors.
+ *
+ * Prints a themed maintenance page with the 'Site off-line' text,
+ * adding the provided error message in the case of 'display_errors'
+ * set to on. Ends the page request; no return.
+ *
+ * @param $error
+ *   The error message to be appended if 'display_errors' is on.
+ */
+function _db_error_page($error = '') {
+  global $db_type;
+  drupal_maintenance_theme();
+  drupal_set_header('HTTP/1.1 503 Service Unavailable');
+  drupal_set_title('Site off-line');
+
+  $message = '<p>The site is currently not available due to technical problems. Please try again later. Thank you for your understanding.</p>';
+  $message .= '<hr /><p><small>If you are the maintainer of this site, please check your database settings in the <code>settings.php</code> file and ensure that your hosting provider\'s database server is running. For more help, see the <a href="http://drupal.org/node/258">handbook</a>, or contact your hosting provider.</small></p>';
+
+  if ($error && ini_get('display_errors')) {
+    $message .= '<p><small>The '. theme('placeholder', $db_type) .' error was: '. theme('placeholder', $error) .'.</small></p>';
+  }
+
+  print theme('maintenance_page', $message);
+  exit;
+}
+
+/**
+ * Returns a boolean depending on the availability of the database.
+ */
+function db_is_active() {
+  global $active_db;
+  return !empty($active_db);
+}
+
+/**
+ * Helper function for db_query().
+ */
+function _db_query_callback($match, $init = FALSE) {
+  static $args = NULL;
+  if ($init) {
+    $args = $match;
+    return;
+  }
+
+  switch ($match[1]) {
+    case '%d': // We must use type casting to int to convert FALSE/NULL/(TRUE?)
+      return (int) array_shift($args); // We don't need db_escape_string as numbers are db-safe
+    case '%s':
+      return db_escape_string(array_shift($args));
+    case '%%':
+      return '%';
+    case '%f':
+      return (float) array_shift($args);
+    case '%b': // binary data
+      return db_encode_blob(array_shift($args));
+  }
+}
+
+/**
+ * Generate placeholders for an array of query arguments of a single type.
+ *
+ * Given a Schema API field type, return correct %-placeholders to
+ * embed in a query
+ *
+ * @param $arguments
+ *  An array with at least one element.
+ * @param $type
+ *   The Schema API type of a field (e.g. 'int', 'text', or 'varchar').
+ */
+function db_placeholders($arguments, $type = 'int') {
+  $placeholder = db_type_placeholder($type);
+  return implode(',', array_fill(0, count($arguments), $placeholder));
+}
+
+/**
+ * Indicates the place holders that should be replaced in _db_query_callback().
+ */
+define('DB_QUERY_REGEXP', '/(%d|%s|%%|%f|%b)/');
+
+/**
+ * Helper function for db_rewrite_sql.
+ *
+ * Collects JOIN and WHERE statements via hook_db_rewrite_sql()
+ * Decides whether to select primary_key or DISTINCT(primary_key)
+ *
+ * @param $query
+ *   Query to be rewritten.
+ * @param $primary_table
+ *   Name or alias of the table which has the primary key field for this query.
+ *   Typical table names would be: {blocks}, {comments}, {forum}, {node},
+ *   {menu}, {term_data} or {vocabulary}. However, in most cases the usual
+ *   table alias (b, c, f, n, m, t or v) is used instead of the table name.
+ * @param $primary_field
+ *   Name of the primary field.
+ * @param $args
+ *   Array of additional arguments.
+ * @return
+ *   An array: join statements, where statements, field or DISTINCT(field).
+ */
+function _db_rewrite_sql($query = '', $primary_table = 'n', $primary_field = 'nid', $args = array()) {
+  $where = array();
+  $join = array();
+  $distinct = FALSE;
+  foreach (module_implements('db_rewrite_sql') as $module) {
+    $result = module_invoke($module, 'db_rewrite_sql', $query, $primary_table, $primary_field, $args);
+    if (isset($result) && is_array($result)) {
+      if (isset($result['where'])) {
+        $where[] = $result['where'];
+      }
+      if (isset($result['join'])) {
+        $join[] = $result['join'];
+      }
+      if (isset($result['distinct']) && $result['distinct']) {
+        $distinct = TRUE;
+      }
+    }
+    elseif (isset($result)) {
+      $where[] = $result;
+    }
+  }
+
+  $where = empty($where) ? '' : '('. implode(') AND (', $where) .')';
+  $join = empty($join) ? '' : implode(' ', $join);
+
+  return array($join, $where, $distinct);
+}
+
+/**
+ * Rewrites node, taxonomy and comment queries. Use it for listing queries. Do not
+ * use FROM table1, table2 syntax, use JOIN instead.
+ *
+ * @param $query
+ *   Query to be rewritten.
+ * @param $primary_table
+ *   Name or alias of the table which has the primary key field for this query.
+ *   Typical table names would be: {blocks}, {comments}, {forum}, {node},
+ *   {menu}, {term_data} or {vocabulary}. However, it is more common to use the
+ *   the usual table aliases: b, c, f, n, m, t or v.
+ * @param $primary_field
+ *   Name of the primary field.
+ * @param $args
+ *   An array of arguments, passed to the implementations of hook_db_rewrite_sql.
+ * @return
+ *   The original query with JOIN and WHERE statements inserted from
+ *   hook_db_rewrite_sql implementations. nid is rewritten if needed.
+ */
+function db_rewrite_sql($query, $primary_table = 'n', $primary_field = 'nid',  $args = array()) {
+  list($join, $where, $distinct) = _db_rewrite_sql($query, $primary_table, $primary_field, $args);
+
+  if ($distinct) {
+    $query = db_distinct_field($primary_table, $primary_field, $query);
+  }
+
+  if (!empty($where) || !empty($join)) {
+    $pattern = '{
+      # Beginning of the string
+      ^
+      ((?P<anonymous_view>
+        # Everything within this set of parentheses is named "anonymous view"
+        (?:
+          [^()]++                   # anything not parentheses
+        |
+          \( (?P>anonymous_view) \)          # an open parenthesis, more "anonymous view" and finally a close parenthesis.
+        )*
+      )[^()]+WHERE)
+    }x';
+    preg_match($pattern, $query, $matches);
+    if (!$where) {
+      $where = '1 = 1';
+    }
+    if ($matches) {
+      $n = strlen($matches[1]);
+      $second_part = substr($query, $n);
+      $first_part = substr($matches[1], 0, $n - 5) ." $join WHERE $where AND ( ";
+      // PHP 4 does not support strrpos for strings. We emulate it.
+      $haystack_reverse = strrev($second_part);
+    }
+    else {
+      $haystack_reverse = strrev($query);
+    }
+    // No need to use strrev on the needle, we supply GROUP, ORDER, LIMIT
+    // reversed.
+    foreach (array('PUORG', 'REDRO', 'TIMIL') as $needle_reverse) {
+      $pos = strpos($haystack_reverse, $needle_reverse);
+      if ($pos !== FALSE) {
+        // All needles are five characters long.
+        $pos += 5;
+        break;
+      }
+    }
+    if ($matches) {
+      if ($pos === FALSE) {
+        $query = $first_part . $second_part .')';
+      }
+      else {
+        $query = $first_part . substr($second_part, 0, -$pos) .')'. substr($second_part, -$pos);
+      }
+    }
+    elseif ($pos === FALSE) {
+      $query .= " $join WHERE $where";
+    }
+    else {
+      $query = substr($query, 0, -$pos) . " $join WHERE $where " . substr($query, -$pos);
+    }
+  }
+
+  return $query;
+}
+
+/**
+ * Restrict a dynamic table, column or constraint name to safe characters.
+ *
+ * Only keeps alphanumeric and underscores.
+ */
+function db_escape_table($string) {
+  return preg_replace('/[^A-Za-z0-9_]+/', '', $string);
+}
+
+/**
+ * @} End of "defgroup database".
+ */
+
+/**
+ * @defgroup schemaapi Schema API
+ * @{
+ *
+ * A Drupal schema definition is an array structure representing one or
+ * more tables and their related keys and indexes. A schema is defined by
+ * hook_schema(), which usually lives in a modulename.install file.
+ *
+ * By implementing hook_schema() and specifying the tables your module
+ * declares, you can easily create and drop these tables on all
+ * supported database engines. You don't have to deal with the
+ * different SQL dialects for table creation and alteration of the
+ * supported database engines.
+ *
+ * hook_schema() should return an array with a key for each table that
+ * the module defines.
+ *
+ * The following keys are defined:
+ *
+ *   - 'description': A string describing this table and its purpose.
+ *     References to other tables should be enclosed in
+ *     curly-brackets.  For example, the node_revisions table
+ *     description field might contain "Stores per-revision title and
+ *     body data for each {node}."
+ *   - 'fields': An associative array ('fieldname' => specification)
+ *     that describes the table's database columns.  The specification
+ *     is also an array.  The following specification parameters are defined:
+ *
+ *     - 'description': A string describing this field and its purpose.
+ *       References to other tables should be enclosed in
+ *       curly-brackets.  For example, the node table vid field
+ *       description might contain "Always holds the largest (most
+ *       recent) {node_revisions}.vid value for this nid."
+ *     - 'type': The generic datatype: 'varchar', 'int', 'serial'
+ *       'float', 'numeric', 'text', 'blob' or 'datetime'.  Most types
+ *       just map to the according database engine specific
+ *       datatypes.  Use 'serial' for auto incrementing fields. This
+ *       will expand to 'int auto_increment' on mysql.
+ *     - 'size': The data size: 'tiny', 'small', 'medium', 'normal',
+ *       'big'.  This is a hint about the largest value the field will
+ *       store and determines which of the database engine specific
+ *       datatypes will be used (e.g. on MySQL, TINYINT vs. INT vs. BIGINT).
+ *       'normal', the default, selects the base type (e.g. on MySQL,
+ *       INT, VARCHAR, BLOB, etc.).
+ *
+ *       Not all sizes are available for all data types. See
+ *       db_type_map() for possible combinations.
+ *     - 'not null': If true, no NULL values will be allowed in this
+ *       database column.  Defaults to false.
+ *     - 'default': The field's default value.  The PHP type of the
+ *       value matters: '', '0', and 0 are all different.  If you
+ *       specify '0' as the default value for a type 'int' field it
+ *       will not work because '0' is a string containing the
+ *       character "zero", not an integer.
+ *     - 'length': The maximal length of a type 'varchar' or 'text'
+ *       field.  Ignored for other field types.
+ *     - 'unsigned': A boolean indicating whether a type 'int', 'float'
+ *       and 'numeric' only is signed or unsigned.  Defaults to
+ *       FALSE.  Ignored for other field types.
+ *     - 'precision', 'scale': For type 'numeric' fields, indicates
+ *       the precision (total number of significant digits) and scale
+ *       (decimal digits right of the decimal point).  Both values are
+ *       mandatory.  Ignored for other field types.
+ *
+ *     All parameters apart from 'type' are optional except that type
+ *     'numeric' columns must specify 'precision' and 'scale'.
+ *
+ *  - 'primary key': An array of one or more key column specifiers (see below)
+ *    that form the primary key.
+ *  - 'unique key': An associative array of unique keys ('keyname' =>
+ *    specification).  Each specification is an array of one or more
+ *    key column specifiers (see below) that form a unique key on the table.
+ *  - 'indexes':  An associative array of indexes ('indexame' =>
+ *    specification).  Each specification is an array of one or more
+ *    key column specifiers (see below) that form an index on the
+ *    table.
+ *
+ * A key column specifier is either a string naming a column or an
+ * array of two elements, column name and length, specifying a prefix
+ * of the named column.
+ *
+ * As an example, here is a SUBSET of the schema definition for
+ * Drupal's 'node' table.  It show four fields (nid, vid, type, and
+ * title), the primary key on field 'nid', a unique key named 'vid' on
+ * field 'vid', and two indexes, one named 'nid' on field 'nid' and
+ * one named 'node_title_type' on the field 'title' and the first four
+ * bytes of the field 'type':
+ *
+ * @code
+ * $schema['node'] = array(
+ *   'fields' => array(
+ *     'nid'      => array('type' => 'serial', 'unsigned' => TRUE, 'not null' => TRUE),
+ *     'vid'      => array('type' => 'int', 'unsigned' => TRUE, 'not null' => TRUE, 'default' => 0),
+ *     'type'     => array('type' => 'varchar', 'length' => 32, 'not null' => TRUE, 'default' => ''),
+ *     'title'    => array('type' => 'varchar', 'length' => 128, 'not null' => TRUE, 'default' => ''),
+ *   ),
+ *   'primary key' => array('nid'),
+ *   'unique keys' => array(
+ *     'vid'     => array('vid')
+ *   ),
+ *   'indexes' => array(
+ *     'nid'                 => array('nid'),
+ *     'node_title_type'     => array('title', array('type', 4)),
+ *   ),
+ * );
+ * @endcode
+ *
+ * @see drupal_install_schema()
+ */
+
+ /**
+ * Create a new table from a Drupal table definition.
+ *
+ * @param $ret
+ *   Array to which query results will be added.
+ * @param $name
+ *   The name of the table to create.
+ * @param $table
+ *   A Schema API table definition array.
+ */
+function db_create_table(&$ret, $name, $table) {
+  $statements = db_create_table_sql($name, $table);
+  foreach ($statements as $statement) {
+    $ret[] = update_sql($statement);
+  }
+}
+
+/**
+ * Return an array of field names from an array of key/index column specifiers.
+ *
+ * This is usually an identity function but if a key/index uses a column prefix
+ * specification, this function extracts just the name.
+ *
+ * @param $fields
+ *   An array of key/index column specifiers.
+ * @return
+ *   An array of field names.
+ */
+function db_field_names($fields) {
+  $ret = array();
+  foreach ($fields as $field) {
+    if (is_array($field)) {
+      $ret[] = $field[0];
+    }
+    else {
+      $ret[] = $field;
+    }
+  }
+  return $ret;
+}
+
+/**
+ * Given a Schema API field type, return the correct %-placeholder.
+ *
+ * Embed the placeholder in a query to be passed to db_query and and pass as an
+ * argument to db_query a value of the specified type.
+ *
+ * @param $type
+ *   The Schema API type of a field.
+ * @return
+ *   The placeholder string to embed in a query for that type.
+ */
+function db_type_placeholder($type) {
+  switch ($type) {
+    case 'varchar':
+    case 'char':
+    case 'text':
+    case 'datetime':
+      return '\'%s\'';
+
+    case 'numeric':
+      // For 'numeric' values, we use '%s', not '\'%s\'' as with
+      // string types, because numeric values should not be enclosed
+      // in quotes in queries (though they can be, at least on mysql
+      // and pgsql).  Numerics should only have [0-9.+-] and
+      // presumably no db's "escape string" function will mess with
+      // those characters.
+      return '%s';
+
+    case 'serial':
+    case 'int':
+      return '%d';
+
+    case 'float':
+      return '%f';
+
+    case 'blob':
+      return '%b';
+  }
+
+  // There is no safe value to return here, so return something that
+  // will cause the query to fail.
+  return 'unsupported type '. $type .'for db_type_placeholder';
+}
+
+/**
+ * @} End of "defgroup schemaapi".
+ */