[Summary view] [Print] [Text view]

   1  <?php
   2  /**
   3   * @file
   4   * Definition of DataHandler class.
   5   */
   6  
   7  /**
   8   * Simple access methods to table data. Can be used on any table, not just Data
   9   * managed tables.
  10   */
  11  class DataHandler {
  12  
  13    // Holds the name of the table that this handler is responsible for.
  14    protected $table;
  15  
  16    /**
  17     * Constructor, call indirectly through DataHandler::instance();
  18     */
  19    protected function __construct($table) {
  20      $this->table = $table;
  21    }
  22  
  23    /**
  24     * Instantiate a DataHandler object.
  25     *
  26     * @param $table
  27     *   The name of the table to access with this DataHandler object.
  28     */
  29    public static function instance($table) {
  30      static $handlers;
  31      if (!isset($handlers[$table])) {
  32        $handlers[$table] = new DataHandler($table);
  33      }
  34      return $handlers[$table];
  35    }
  36  
  37    /**
  38     * Getter.
  39     */
  40    public function __get($name) {
  41      return $this->$name;
  42    }
  43  
  44    /**
  45     * Load a record.
  46     */
  47    public function load($keys) {
  48      $where = $values = array();
  49      $schema = drupal_get_schema($this->table);
  50      $fields = $schema['fields'];
  51      foreach ($keys as $key => $value) {
  52        // Return if a key does not exist.
  53        if (!isset($fields[$key]['type'])) {
  54          return FALSE;
  55        }
  56        $where[] = db_escape_string($key) ." = ". db_type_placeholder($fields[$key]['type']);
  57        $values[] = $value;
  58      }
  59  
  60      if (!empty($where)) {
  61        $result = db_query('SELECT * FROM {'. db_escape_table($this->table) .'} WHERE '. implode(' AND ', $where), $values);
  62        $results = array();
  63        while ($row = db_fetch_array($result)) {
  64          $results[] = $row;
  65        }
  66        return count($results) ? $results : FALSE;
  67      }
  68      return FALSE;
  69    }
  70  
  71    /**
  72     * Insert a record.
  73     *
  74     * @see drupal_write_record().
  75     *
  76     * @param $record
  77     *   An array that is the record to save to this handler's table.
  78     */
  79    public function insert(&$record) {
  80      $result = drupal_write_record($this->table, $record);
  81      module_invoke_all('data_insert', $record, $this->table);
  82      return $result;
  83    }
  84  
  85    /**
  86     * Update a record.
  87     *
  88     * @see drupal_write_record().
  89     *
  90     * @param $record
  91     *   An array that is the record to save to this handler's table.
  92     * @param $update
  93     *   A string or an array of strings that defines the keys to use for
  94     *   this update.
  95     */
  96    public function update(&$record, $update) {
  97      $result = drupal_write_record($this->table, $record, $update);
  98      module_invoke_all('data_update', $record, $this->table);
  99      return $result;
 100    }
 101  
 102    /**
 103     * Save one or more records to the table.
 104     *
 105     * If $update is given, method will try to update before.
 106     *
 107     * This method is more comfortable, but slower than using insert() or
 108     * update().
 109     *
 110     * @param $record
 111     *   An array that is the record to save to this handler's table.
 112     * @param
 113     *   A string or an array of strings that defines the keys to use for
 114     *   this update.
 115     */
 116    public function save(&$record, $update = array()) {
 117      if (is_string($update)) {
 118        $update = array($update);
 119      }
 120      if (is_array($update)) {
 121        $keys = array();
 122        foreach ($update as $key) {
 123          $keys[$key] = $record[$key];
 124        }
 125        if (count($keys)) {
 126          if ($this->load($keys)) {
 127            return $this->update($record, $update);
 128          }
 129        }
 130      }
 131      return $this->insert($record);
 132    }
 133  
 134    /**
 135     * Delete one or more records from the table.
 136     *
 137     * @param $clause
 138     *   An array where the keys are columns in the data table and the values are
 139     *   the values to filter on. This array will be turned into the where clause
 140     *   of the delete query.
 141     *
 142     *   Example:
 143     *
 144     *   array(
 145     *     'feed_nid' => 10,
 146     *     'timestamp' => array(
 147     *       '<',
 148     *       1255623780,
 149     *     ),
 150     *   );
 151     */
 152    public function delete($clause) {
 153      $query = new DataQuery($this->table);
 154      $schema = drupal_get_schema($this->table);
 155      $fields = $schema['fields'];
 156      foreach ($clause as $key => $value) {
 157        $operator = '=';
 158        if (is_array($value)) {
 159          $operator = array_shift($value);
 160          $value = array_shift($value);
 161        }
 162        $query->addWhere(db_escape_table($this->table) .'.'. db_escape_string($key) ." ". $operator ." ". db_type_placeholder($fields[$key]['type']), $value);
 163      }
 164      drupal_alter('data_delete_query', $query, $this->table);
 165      if (!empty($query->where)) {
 166        $query->execute();
 167      }
 168      return db_affected_rows();
 169    }
 170  
 171    /**
 172     * Empty data table.
 173     */
 174    public function truncate() {
 175      db_query('TRUNCATE TABLE {'. db_escape_table($this->table) .'}');
 176    }
 177  }
 178  
 179  /**
 180   * Builds and executes a query, only delete queries are supported at the moment.
 181   */
 182  class DataQuery {
 183  
 184    public $subject, $table, $from, $join, $where;
 185  
 186    /**
 187     * Creates an empty query.
 188     *
 189     * @param $table
 190     *   Base table to operate on, also the subject table to delete
 191     *   from.
 192     */
 193    public function __construct($table) {
 194      $this->table = db_escape_table($table);
 195      $this->subject = array($this->table => $this->table);
 196      $this->from = $this->table;
 197      $this->join = array();
 198      $this->where = array();
 199    }
 200  
 201    /**
 202     * Add a subject table.
 203     */
 204    public function addSubject($table) {
 205      $this->subject[$table] = $table;
 206    }
 207  
 208    /**
 209     * Add a join.
 210     *
 211     * @param $table
 212     *   The table to join to.
 213     * @param $join
 214     *   The columns to join on.
 215     */
 216    public function addJoin($table, $join, $type = 'INNER JOIN') {
 217      $this->join[$table] = array(
 218        $join,
 219        $type,
 220      );
 221    }
 222  
 223    /**
 224     * Add a where clause.
 225     *
 226     * @param $clause
 227     *   The actual clause. Caller is responsible for referring to existing fields
 228     *   and supplying correct placeholder for value.
 229     * @param $value
 230     *   The value the clause compares against.
 231     */
 232    public function addWhere($clause, $value = NULL) {
 233      $this->where[$clause] = $value;
 234    }
 235  
 236    /**
 237     * Build and execute a query.
 238     */
 239    public function execute() {
 240      $table = db_escape_table($this->table);
 241      $query = "DELETE ". implode(', ', $this->subject);
 242      $query .= " FROM {{$table}} {$table}";
 243      if (!empty($this->join)) {
 244        foreach ($this->join as $table => $join) {
 245          $table = db_escape_table($table);
 246          $clause = array_shift($join);
 247          $join = array_shift($join);
 248          $query .= " $join {{$table}} $table ON $clause";
 249        }
 250      }
 251      $where = $values = array();
 252      foreach ($this->where as $k => $v) {
 253        $where[] = $k;
 254        if ($v !== NULL) {
 255          $values[] = $v;
 256        }
 257      }
 258      if (!empty($where)) {
 259        $query .= " WHERE ". implode(' AND ', $where);
 260      }
 261      return db_query($query, $values);
 262    }
 263  }