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   1  <?php
   2  // $Id: database.pgsql.inc,v 1.68.2.11 2010/12/15 20:41:10 goba Exp $
   3  
   4  /**
   5   * @file
   6   * Database interface code for PostgreSQL database servers.
   7   */
   8  
   9  /**
  10   * @ingroup database
  11   * @{
  12   */
  13  
  14  /**
  15   * Report database status.
  16   */
  17  function db_status_report() {
  18    $t = get_t();
  19  
  20    $version = db_version();
  21  
  22    $form['pgsql'] = array(
  23      'title' => $t('PostgreSQL database'),
  24      'value' => $version,
  25    );
  26  
  27    if (version_compare($version, DRUPAL_MINIMUM_PGSQL) < 0) {
  28      $form['pgsql']['severity'] = REQUIREMENT_ERROR;
  29      $form['pgsql']['description'] = $t('Your PostgreSQL Server is too old. Drupal requires at least PostgreSQL %version.', array('%version' => DRUPAL_MINIMUM_PGSQL));
  30    }
  31  
  32    return $form;
  33  }
  34  
  35  /**
  36   * Returns the version of the database server currently in use.
  37   *
  38   * @return Database server version
  39   */
  40  function db_version() {
  41    return db_result(db_query("SHOW SERVER_VERSION"));
  42  }
  43  
  44  /**
  45   * Initialize a database connection.
  46   */
  47  function db_connect($url) {
  48    // Check if PostgreSQL support is present in PHP
  49    if (!function_exists('pg_connect')) {
  50      _db_error_page('Unable to use the PostgreSQL database because the PostgreSQL extension for PHP is not installed. Check your <code>php.ini</code> to see how you can enable it.');
  51    }
  52  
  53    $url = parse_url($url);
  54    $conn_string = '';
  55  
  56    // Decode url-encoded information in the db connection string
  57    if (isset($url['user'])) {
  58      $conn_string .= ' user='. urldecode($url['user']);
  59    }
  60    if (isset($url['pass'])) {
  61      $conn_string .= ' password='. urldecode($url['pass']);
  62    }
  63    if (isset($url['host'])) {
  64      $conn_string .= ' host='. urldecode($url['host']);
  65    }
  66    if (isset($url['path'])) {
  67      $conn_string .= ' dbname='. substr(urldecode($url['path']), 1);
  68    }
  69    if (isset($url['port'])) {
  70      $conn_string .= ' port='. urldecode($url['port']);
  71    }
  72  
  73    // pg_last_error() does not return a useful error message for database
  74    // connection errors. We must turn on error tracking to get at a good error
  75    // message, which will be stored in $php_errormsg.
  76    $track_errors_previous = ini_get('track_errors');
  77    ini_set('track_errors', 1);
  78  
  79    $connection = @pg_connect($conn_string);
  80    if (!$connection) {
  81      require_once  './includes/unicode.inc';
  82      _db_error_page(decode_entities($php_errormsg));
  83    }
  84  
  85    // Restore error tracking setting
  86    ini_set('track_errors', $track_errors_previous);
  87  
  88    pg_query($connection, "set client_encoding=\"UTF8\"");
  89    return $connection;
  90  }
  91  
  92  /**
  93   * Runs a basic query in the active database.
  94   *
  95   * User-supplied arguments to the query should be passed in as separate
  96   * parameters so that they can be properly escaped to avoid SQL injection
  97   * attacks.
  98   *
  99   * @param $query
 100   *   A string containing an SQL query.
 101   * @param ...
 102   *   A variable number of arguments which are substituted into the query
 103   *   using printf() syntax. Instead of a variable number of query arguments,
 104   *   you may also pass a single array containing the query arguments.
 105   *
 106   *   Valid %-modifiers are: %s, %d, %f, %b (binary data, do not enclose
 107   *   in '') and %%.
 108   *
 109   *   NOTE: using this syntax will cast NULL and FALSE values to decimal 0,
 110   *   and TRUE values to decimal 1.
 111   *
 112   * @return
 113   *   A database query result resource, or FALSE if the query was not
 114   *   executed correctly.
 115   */
 116  function db_query($query) {
 117    $args = func_get_args();
 118    array_shift($args);
 119    $query = db_prefix_tables($query);
 120    if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax
 121      $args = $args[0];
 122    }
 123    _db_query_callback($args, TRUE);
 124    $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);
 125    return _db_query($query);
 126  }
 127  
 128  /**
 129   * Helper function for db_query().
 130   */
 131  function _db_query($query, $debug = 0) {
 132    global $active_db, $last_result, $queries;
 133  
 134    if (variable_get('dev_query', 0)) {
 135      list($usec, $sec) = explode(' ', microtime());
 136      $timer = (float)$usec + (float)$sec;
 137    }
 138  
 139    $last_result = pg_query($active_db, $query);
 140  
 141    if (variable_get('dev_query', 0)) {
 142      $bt = debug_backtrace();
 143      $query = $bt[2]['function'] ."\n". $query;
 144      list($usec, $sec) = explode(' ', microtime());
 145      $stop = (float)$usec + (float)$sec;
 146      $diff = $stop - $timer;
 147      $queries[] = array($query, $diff);
 148    }
 149  
 150    if ($debug) {
 151      print '<p>query: '. $query .'<br />error:'. pg_last_error($active_db) .'</p>';
 152    }
 153  
 154    if ($last_result !== FALSE) {
 155      return $last_result;
 156    }
 157    else {
 158      // Indicate to drupal_error_handler that this is a database error.
 159      $DB_ERROR} = TRUE;
 160      trigger_error(check_plain(pg_last_error($active_db) ."\nquery: ". $query), E_USER_WARNING);
 161      return FALSE;
 162    }
 163  }
 164  
 165  /**
 166   * Fetch one result row from the previous query as an object.
 167   *
 168   * @param $result
 169   *   A database query result resource, as returned from db_query().
 170   * @return
 171   *   An object representing the next row of the result, or FALSE. The attributes
 172   *   of this object are the table fields selected by the query.
 173   */
 174  function db_fetch_object($result) {
 175    if ($result) {
 176      return pg_fetch_object($result);
 177    }
 178  }
 179  
 180  /**
 181   * Fetch one result row from the previous query as an array.
 182   *
 183   * @param $result
 184   *   A database query result resource, as returned from db_query().
 185   * @return
 186   *   An associative array representing the next row of the result, or FALSE.
 187   *   The keys of this object are the names of the table fields selected by the
 188   *   query, and the values are the field values for this result row.
 189   */
 190  function db_fetch_array($result) {
 191    if ($result) {
 192      return pg_fetch_assoc($result);
 193    }
 194  }
 195  
 196  /**
 197   * Return an individual result field from the previous query.
 198   *
 199   * Only use this function if exactly one field is being selected; otherwise,
 200   * use db_fetch_object() or db_fetch_array().
 201   *
 202   * @param $result
 203   *   A database query result resource, as returned from db_query().
 204   * @return
 205   *   The resulting field or FALSE.
 206   */
 207  function db_result($result) {
 208    if ($result && pg_num_rows($result) > 0) {
 209      $array = pg_fetch_row($result);
 210      return $array[0];
 211    }
 212    return FALSE;
 213  }
 214  
 215  /**
 216   * Determine whether the previous query caused an error.
 217   */
 218  function db_error() {
 219    global $active_db;
 220    return pg_last_error($active_db);
 221  }
 222  
 223  /**
 224   * Returns the last insert id. This function is thread safe.
 225   *
 226   * @param $table
 227   *   The name of the table you inserted into.
 228   * @param $field
 229   *   The name of the autoincrement field.
 230   */
 231  function db_last_insert_id($table, $field) {
 232    return db_result(db_query("SELECT CURRVAL('{". db_escape_table($table) ."}_". db_escape_table($field) ."_seq')"));
 233  }
 234  
 235  /**
 236   * Determine the number of rows changed by the preceding query.
 237   */
 238  function db_affected_rows() {
 239    global $last_result;
 240    return empty($last_result) ? 0 : pg_affected_rows($last_result);
 241  }
 242  
 243  /**
 244   * Runs a limited-range query in the active database.
 245   *
 246   * Use this as a substitute for db_query() when a subset of the query
 247   * is to be returned.
 248   * User-supplied arguments to the query should be passed in as separate
 249   * parameters so that they can be properly escaped to avoid SQL injection
 250   * attacks.
 251   *
 252   * @param $query
 253   *   A string containing an SQL query.
 254   * @param ...
 255   *   A variable number of arguments which are substituted into the query
 256   *   using printf() syntax. Instead of a variable number of query arguments,
 257   *   you may also pass a single array containing the query arguments.
 258   *   Valid %-modifiers are: %s, %d, %f, %b (binary data, do not enclose
 259   *   in '') and %%.
 260   *
 261   *   NOTE: using this syntax will cast NULL and FALSE values to decimal 0,
 262   *   and TRUE values to decimal 1.
 263   *
 264   * @param $from
 265   *   The first result row to return.
 266   * @param $count
 267   *   The maximum number of result rows to return.
 268   * @return
 269   *   A database query result resource, or FALSE if the query was not executed
 270   *   correctly.
 271   */
 272  function db_query_range($query) {
 273    $args = func_get_args();
 274    $count = array_pop($args);
 275    $from = array_pop($args);
 276    array_shift($args);
 277  
 278    $query = db_prefix_tables($query);
 279    if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax
 280      $args = $args[0];
 281    }
 282    _db_query_callback($args, TRUE);
 283    $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);
 284    $query .= ' LIMIT '. (int)$count .' OFFSET '. (int)$from;
 285    return _db_query($query);
 286  }
 287  
 288  /**
 289   * Runs a SELECT query and stores its results in a temporary table.
 290   *
 291   * Use this as a substitute for db_query() when the results need to stored
 292   * in a temporary table. Temporary tables exist for the duration of the page
 293   * request.
 294   * User-supplied arguments to the query should be passed in as separate parameters
 295   * so that they can be properly escaped to avoid SQL injection attacks.
 296   *
 297   * Note that if you need to know how many results were returned, you should do
 298   * a SELECT COUNT(*) on the temporary table afterwards. db_affected_rows() does
 299   * not give consistent result across different database types in this case.
 300   *
 301   * @param $query
 302   *   A string containing a normal SELECT SQL query.
 303   * @param ...
 304   *   A variable number of arguments which are substituted into the query
 305   *   using printf() syntax. The query arguments can be enclosed in one
 306   *   array instead.
 307   *   Valid %-modifiers are: %s, %d, %f, %b (binary data, do not enclose
 308   *   in '') and %%.
 309   *
 310   *   NOTE: using this syntax will cast NULL and FALSE values to decimal 0,
 311   *   and TRUE values to decimal 1.
 312   *
 313   * @param $table
 314   *   The name of the temporary table to select into. This name will not be
 315   *   prefixed as there is no risk of collision.
 316   * @return
 317   *   A database query result resource, or FALSE if the query was not executed
 318   *   correctly.
 319   */
 320  function db_query_temporary($query) {
 321    $args = func_get_args();
 322    $tablename = array_pop($args);
 323    array_shift($args);
 324  
 325    $query = preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE '. $tablename .' AS SELECT', db_prefix_tables($query));
 326    if (isset($args[0]) and is_array($args[0])) { // 'All arguments in one array' syntax
 327      $args = $args[0];
 328    }
 329    _db_query_callback($args, TRUE);
 330    $query = preg_replace_callback(DB_QUERY_REGEXP, '_db_query_callback', $query);
 331    return _db_query($query);
 332  }
 333  
 334  /**
 335   * Returns a properly formatted Binary Large OBject value.
 336   * In case of PostgreSQL encodes data for insert into bytea field.
 337   *
 338   * @param $data
 339   *   Data to encode.
 340   * @return
 341   *  Encoded data.
 342   */
 343  function db_encode_blob($data) {
 344    return "'". pg_escape_bytea($data) ."'";
 345  }
 346  
 347  /**
 348   * Returns text from a Binary Large OBject value.
 349   * In case of PostgreSQL decodes data after select from bytea field.
 350   *
 351   * @param $data
 352   *   Data to decode.
 353   * @return
 354   *  Decoded data.
 355   */
 356  function db_decode_blob($data) {
 357    return pg_unescape_bytea($data);
 358  }
 359  
 360  /**
 361   * Prepare user input for use in a database query, preventing SQL injection attacks.
 362   * Note: This function requires PostgreSQL 7.2 or later.
 363   */
 364  function db_escape_string($text) {
 365    return pg_escape_string($text);
 366  }
 367  
 368  /**
 369   * Lock a table.
 370   * This function automatically starts a transaction.
 371   */
 372  function db_lock_table($table) {
 373    db_query('BEGIN; LOCK TABLE {'. db_escape_table($table) .'} IN EXCLUSIVE MODE');
 374  }
 375  
 376  /**
 377   * Unlock all locked tables.
 378   * This function automatically commits a transaction.
 379   */
 380  function db_unlock_tables() {
 381    db_query('COMMIT');
 382  }
 383  
 384  /**
 385   * Check if a table exists.
 386   *
 387   * @param $table
 388   *   The name of the table.
 389   *
 390   * @return
 391   *   TRUE if the table exists, and FALSE if the table does not exist.
 392   */
 393  function db_table_exists($table) {
 394    return (bool) db_result(db_query("SELECT COUNT(*) FROM pg_class WHERE relname = '{". db_escape_table($table) ."}'"));
 395  }
 396  
 397  /**
 398   * Check if a column exists in the given table.
 399   *
 400   * @param $table
 401   *   The name of the table.
 402   * @param $column
 403   *   The name of the column.
 404   *
 405   * @return
 406   *   TRUE if the column exists, and FALSE if the column does not exist.
 407   */
 408  function db_column_exists($table, $column) {
 409    return (bool) db_result(db_query("SELECT COUNT(pg_attribute.attname) FROM pg_class, pg_attribute WHERE pg_attribute.attrelid = pg_class.oid AND pg_class.relname = '{". db_escape_table($table) ."}' AND attname = '". db_escape_table($column) ."'"));
 410  }
 411  
 412  /**
 413   * Verify if the database is set up correctly.
 414   */
 415  function db_check_setup() {
 416    $t = get_t();
 417  
 418    $encoding = db_result(db_query('SHOW server_encoding'));
 419    if (!in_array(strtolower($encoding), array('unicode', 'utf8'))) {
 420      drupal_set_message($t('Your PostgreSQL database is set up with the wrong character encoding (%encoding). It is possible it will not work as expected. It is advised to recreate it with UTF-8/Unicode encoding. More information can be found in the <a href="@url">PostgreSQL documentation</a>.', array('%encoding' => $encoding, '@url' => 'http://www.postgresql.org/docs/7.4/interactive/multibyte.html')), 'status');
 421    }
 422  }
 423  
 424  /**
 425   * @} End of "ingroup database".
 426   */
 427  
 428  /**
 429   * @ingroup schemaapi
 430   * @{
 431   */
 432  
 433  /**
 434   * This maps a generic data type in combination with its data size
 435   * to the engine-specific data type.
 436   */
 437  function db_type_map() {
 438    // Put :normal last so it gets preserved by array_flip.  This makes
 439    // it much easier for modules (such as schema.module) to map
 440    // database types back into schema types.
 441    $map = array(
 442      'varchar:normal' => 'varchar',
 443      'char:normal' => 'character',
 444  
 445      'text:tiny' => 'text',
 446      'text:small' => 'text',
 447      'text:medium' => 'text',
 448      'text:big' => 'text',
 449      'text:normal' => 'text',
 450  
 451      'int:tiny' => 'smallint',
 452      'int:small' => 'smallint',
 453      'int:medium' => 'int',
 454      'int:big' => 'bigint',
 455      'int:normal' => 'int',
 456  
 457      'float:tiny' => 'real',
 458      'float:small' => 'real',
 459      'float:medium' => 'real',
 460      'float:big' => 'double precision',
 461      'float:normal' => 'real',
 462  
 463      'numeric:normal' => 'numeric',
 464  
 465      'blob:big' => 'bytea',
 466      'blob:normal' => 'bytea',
 467  
 468      'datetime:normal' => 'timestamp without time zone',
 469  
 470      'serial:tiny' => 'serial',
 471      'serial:small' => 'serial',
 472      'serial:medium' => 'serial',
 473      'serial:big' => 'bigserial',
 474      'serial:normal' => 'serial',
 475    );
 476    return $map;
 477  }
 478  
 479  /**
 480   * Generate SQL to create a new table from a Drupal schema definition.
 481   *
 482   * @param $name
 483   *   The name of the table to create.
 484   * @param $table
 485   *   A Schema API table definition array.
 486   * @return
 487   *   An array of SQL statements to create the table.
 488   */
 489  function db_create_table_sql($name, $table) {
 490    $sql_fields = array();
 491    foreach ($table['fields'] as $field_name => $field) {
 492      $sql_fields[] = _db_create_field_sql($field_name, _db_process_field($field));
 493    }
 494  
 495    $sql_keys = array();
 496    if (isset($table['primary key']) && is_array($table['primary key'])) {
 497      $sql_keys[] = 'PRIMARY KEY ('. implode(', ', $table['primary key']) .')';
 498    }
 499    if (isset($table['unique keys']) && is_array($table['unique keys'])) {
 500      foreach ($table['unique keys'] as $key_name => $key) {
 501        $sql_keys[] = 'CONSTRAINT {'. $name .'}_'. $key_name .'_key UNIQUE ('. implode(', ', $key) .')';
 502      }
 503    }
 504  
 505    $sql = "CREATE TABLE {". $name ."} (\n\t";
 506    $sql .= implode(",\n\t", $sql_fields);
 507    if (count($sql_keys) > 0) {
 508      $sql .= ",\n\t";
 509    }
 510    $sql .= implode(",\n\t", $sql_keys);
 511    $sql .= "\n)";
 512    $statements[] = $sql;
 513  
 514    if (isset($table['indexes']) && is_array($table['indexes'])) {
 515      foreach ($table['indexes'] as $key_name => $key) {
 516        $statements[] = _db_create_index_sql($name, $key_name, $key);
 517      }
 518    }
 519  
 520    return $statements;
 521  }
 522  
 523  function _db_create_index_sql($table, $name, $fields) {
 524    $query = 'CREATE INDEX {'. $table .'}_'. $name .'_idx ON {'. $table .'} (';
 525    $query .= _db_create_key_sql($fields) .')';
 526    return $query;
 527  }
 528  
 529  function _db_create_key_sql($fields) {
 530    $ret = array();
 531    foreach ($fields as $field) {
 532      if (is_array($field)) {
 533        $ret[] = 'substr('. $field[0] .', 1, '. $field[1] .')';
 534      }
 535      else {
 536        $ret[] = $field;
 537      }
 538    }
 539    return implode(', ', $ret);
 540  }
 541  
 542  function _db_create_keys(&$ret, $table, $new_keys) {
 543    if (isset($new_keys['primary key'])) {
 544      db_add_primary_key($ret, $table, $new_keys['primary key']);
 545    }
 546    if (isset($new_keys['unique keys'])) {
 547      foreach ($new_keys['unique keys'] as $name => $fields) {
 548        db_add_unique_key($ret, $table, $name, $fields);
 549      }
 550    }
 551    if (isset($new_keys['indexes'])) {
 552      foreach ($new_keys['indexes'] as $name => $fields) {
 553        db_add_index($ret, $table, $name, $fields);
 554      }
 555    }
 556  }
 557  
 558  /**
 559   * Set database-engine specific properties for a field.
 560   *
 561   * @param $field
 562   *   A field description array, as specified in the schema documentation.
 563   */
 564  function _db_process_field($field) {
 565    if (!isset($field['size'])) {
 566      $field['size'] = 'normal';
 567    }
 568    // Set the correct database-engine specific datatype.
 569    if (!isset($field['pgsql_type'])) {
 570      $map = db_type_map();
 571      $field['pgsql_type'] = $map[$field['type'] .':'. $field['size']];
 572    }
 573    if ($field['type'] == 'serial') {
 574      unset($field['not null']);
 575    }
 576    return $field;
 577  }
 578  
 579  /**
 580   * Create an SQL string for a field to be used in table creation or alteration.
 581   *
 582   * Before passing a field out of a schema definition into this function it has
 583   * to be processed by _db_process_field().
 584   *
 585   * @param $name
 586   *    Name of the field.
 587   * @param $spec
 588   *    The field specification, as per the schema data structure format.
 589   */
 590  function _db_create_field_sql($name, $spec) {
 591    $sql = $name .' '. $spec['pgsql_type'];
 592  
 593    if ($spec['type'] == 'serial') {
 594      unset($spec['not null']);
 595    }
 596  
 597    if (in_array($spec['type'], array('varchar', 'char', 'text')) && isset($spec['length'])) {
 598      $sql .= '('. $spec['length'] .')';
 599    }
 600    elseif (isset($spec['precision']) && isset($spec['scale'])) {
 601      $sql .= '('. $spec['precision'] .', '. $spec['scale'] .')';
 602    }
 603  
 604    if (!empty($spec['unsigned'])) {
 605      $sql .= " CHECK ($name >= 0)";
 606    }
 607  
 608    if (isset($spec['not null']) && $spec['not null']) {
 609      $sql .= ' NOT NULL';
 610    }
 611    if (isset($spec['default'])) {
 612      $default = is_string($spec['default']) ? "'". $spec['default'] ."'" : $spec['default'];
 613      $sql .= " default $default";
 614    }
 615  
 616    return $sql;
 617  }
 618  
 619  /**
 620   * Rename a table.
 621   *
 622   * @param $ret
 623   *   Array to which query results will be added.
 624   * @param $table
 625   *   The table to be renamed.
 626   * @param $new_name
 627   *   The new name for the table.
 628   */
 629  function db_rename_table(&$ret, $table, $new_name) {
 630    $ret[] = update_sql('ALTER TABLE {'. $table .'} RENAME TO {'. $new_name .'}');
 631  }
 632  
 633  /**
 634   * Drop a table.
 635   *
 636   * @param $ret
 637   *   Array to which query results will be added.
 638   * @param $table
 639   *   The table to be dropped.
 640   */
 641  function db_drop_table(&$ret, $table) {
 642    $ret[] = update_sql('DROP TABLE {'. $table .'}');
 643  }
 644  
 645  /**
 646   * Add a new field to a table.
 647   *
 648   * @param $ret
 649   *   Array to which query results will be added.
 650   * @param $table
 651   *   Name of the table to be altered.
 652   * @param $field
 653   *   Name of the field to be added.
 654   * @param $spec
 655   *   The field specification array, as taken from a schema definition.
 656   *   The specification may also contain the key 'initial', the newly
 657   *   created field will be set to the value of the key in all rows.
 658   *   This is most useful for creating NOT NULL columns with no default
 659   *   value in existing tables.
 660   * @param $new_keys
 661   *   Optional keys and indexes specification to be created on the
 662   *   table along with adding the field. The format is the same as a
 663   *   table specification but without the 'fields' element.  If you are
 664   *   adding a type 'serial' field, you MUST specify at least one key
 665   *   or index including it in this array. @see db_change_field for more
 666   *   explanation why.
 667   */
 668  function db_add_field(&$ret, $table, $field, $spec, $new_keys = array()) {
 669    $fixnull = FALSE;
 670    if (!empty($spec['not null']) && !isset($spec['default'])) {
 671      $fixnull = TRUE;
 672      $spec['not null'] = FALSE;
 673    }
 674    $query = 'ALTER TABLE {'. $table .'} ADD COLUMN ';
 675    $query .= _db_create_field_sql($field, _db_process_field($spec));
 676    $ret[] = update_sql($query);
 677    if (isset($spec['initial'])) {
 678      // All this because update_sql does not support %-placeholders.
 679      $sql = 'UPDATE {'. $table .'} SET '. $field .' = '. db_type_placeholder($spec['type']);
 680      $result = db_query($sql, $spec['initial']);
 681      $ret[] = array('success' => $result !== FALSE, 'query' => check_plain($sql .' ('. $spec['initial'] .')'));
 682    }
 683    if ($fixnull) {
 684      $ret[] = update_sql("ALTER TABLE {". $table ."} ALTER $field SET NOT NULL");
 685    }
 686    if (isset($new_keys)) {
 687      _db_create_keys($ret, $table, $new_keys);
 688    }
 689  }
 690  
 691  /**
 692   * Drop a field.
 693   *
 694   * @param $ret
 695   *   Array to which query results will be added.
 696   * @param $table
 697   *   The table to be altered.
 698   * @param $field
 699   *   The field to be dropped.
 700   */
 701  function db_drop_field(&$ret, $table, $field) {
 702    $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP COLUMN '. $field);
 703  }
 704  
 705  /**
 706   * Set the default value for a field.
 707   *
 708   * @param $ret
 709   *   Array to which query results will be added.
 710   * @param $table
 711   *   The table to be altered.
 712   * @param $field
 713   *   The field to be altered.
 714   * @param $default
 715   *   Default value to be set. NULL for 'default NULL'.
 716   */
 717  function db_field_set_default(&$ret, $table, $field, $default) {
 718    if ($default == NULL) {
 719      $default = 'NULL';
 720    }
 721    else {
 722      $default = is_string($default) ? "'$default'" : $default;
 723    }
 724  
 725    $ret[] = update_sql('ALTER TABLE {'. $table .'} ALTER COLUMN '. $field .' SET DEFAULT '. $default);
 726  }
 727  
 728  /**
 729   * Set a field to have no default value.
 730   *
 731   * @param $ret
 732   *   Array to which query results will be added.
 733   * @param $table
 734   *   The table to be altered.
 735   * @param $field
 736   *   The field to be altered.
 737   */
 738  function db_field_set_no_default(&$ret, $table, $field) {
 739    $ret[] = update_sql('ALTER TABLE {'. $table .'} ALTER COLUMN '. $field .' DROP DEFAULT');
 740  }
 741  
 742  /**
 743   * Add a primary key.
 744   *
 745   * @param $ret
 746   *   Array to which query results will be added.
 747   * @param $table
 748   *   The table to be altered.
 749   * @param $fields
 750   *   Fields for the primary key.
 751   */
 752  function db_add_primary_key(&$ret, $table, $fields) {
 753    $ret[] = update_sql('ALTER TABLE {'. $table .'} ADD PRIMARY KEY ('.
 754      implode(',', $fields) .')');
 755  }
 756  
 757  /**
 758   * Drop the primary key.
 759   *
 760   * @param $ret
 761   *   Array to which query results will be added.
 762   * @param $table
 763   *   The table to be altered.
 764   */
 765  function db_drop_primary_key(&$ret, $table) {
 766    $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP CONSTRAINT {'. $table .'}_pkey');
 767  }
 768  
 769  /**
 770   * Add a unique key.
 771   *
 772   * @param $ret
 773   *   Array to which query results will be added.
 774   * @param $table
 775   *   The table to be altered.
 776   * @param $name
 777   *   The name of the key.
 778   * @param $fields
 779   *   An array of field names.
 780   */
 781  function db_add_unique_key(&$ret, $table, $name, $fields) {
 782    $name = '{'. $table .'}_'. $name .'_key';
 783    $ret[] = update_sql('ALTER TABLE {'. $table .'} ADD CONSTRAINT '.
 784      $name .' UNIQUE ('. implode(',', $fields) .')');
 785  }
 786  
 787  /**
 788   * Drop a unique key.
 789   *
 790   * @param $ret
 791   *   Array to which query results will be added.
 792   * @param $table
 793   *   The table to be altered.
 794   * @param $name
 795   *   The name of the key.
 796   */
 797  function db_drop_unique_key(&$ret, $table, $name) {
 798    $name = '{'. $table .'}_'. $name .'_key';
 799    $ret[] = update_sql('ALTER TABLE {'. $table .'} DROP CONSTRAINT '. $name);
 800  }
 801  
 802  /**
 803   * Add an index.
 804   *
 805   * @param $ret
 806   *   Array to which query results will be added.
 807   * @param $table
 808   *   The table to be altered.
 809   * @param $name
 810   *   The name of the index.
 811   * @param $fields
 812   *   An array of field names.
 813   */
 814  function db_add_index(&$ret, $table, $name, $fields) {
 815    $ret[] = update_sql(_db_create_index_sql($table, $name, $fields));
 816  }
 817  
 818  /**
 819   * Drop an index.
 820   *
 821   * @param $ret
 822   *   Array to which query results will be added.
 823   * @param $table
 824   *   The table to be altered.
 825   * @param $name
 826   *   The name of the index.
 827   */
 828  function db_drop_index(&$ret, $table, $name) {
 829    $name = '{'. $table .'}_'. $name .'_idx';
 830    $ret[] = update_sql('DROP INDEX '. $name);
 831  }
 832  
 833  /**
 834   * Change a field definition.
 835   *
 836   * IMPORTANT NOTE: To maintain database portability, you have to explicitly
 837   * recreate all indices and primary keys that are using the changed field.
 838   *
 839   * That means that you have to drop all affected keys and indexes with
 840   * db_drop_{primary_key,unique_key,index}() before calling db_change_field().
 841   * To recreate the keys and indices, pass the key definitions as the
 842   * optional $new_keys argument directly to db_change_field().
 843   *
 844   * For example, suppose you have:
 845   * @code
 846   * $schema['foo'] = array(
 847   *   'fields' => array(
 848   *     'bar' => array('type' => 'int', 'not null' => TRUE)
 849   *   ),
 850   *   'primary key' => array('bar')
 851   * );
 852   * @endcode
 853   * and you want to change foo.bar to be type serial, leaving it as the
 854   * primary key.  The correct sequence is:
 855   * @code
 856   * db_drop_primary_key($ret, 'foo');
 857   * db_change_field($ret, 'foo', 'bar', 'bar',
 858   *   array('type' => 'serial', 'not null' => TRUE),
 859   *   array('primary key' => array('bar')));
 860   * @endcode
 861   *
 862   * The reasons for this are due to the different database engines:
 863   *
 864   * On PostgreSQL, changing a field definition involves adding a new field
 865   * and dropping an old one which* causes any indices, primary keys and
 866   * sequences (from serial-type fields) that use the changed field to be dropped.
 867   *
 868   * On MySQL, all type 'serial' fields must be part of at least one key
 869   * or index as soon as they are created.  You cannot use
 870   * db_add_{primary_key,unique_key,index}() for this purpose because
 871   * the ALTER TABLE command will fail to add the column without a key
 872   * or index specification.  The solution is to use the optional
 873   * $new_keys argument to create the key or index at the same time as
 874   * field.
 875   *
 876   * You could use db_add_{primary_key,unique_key,index}() in all cases
 877   * unless you are converting a field to be type serial. You can use
 878   * the $new_keys argument in all cases.
 879   *
 880   * @param $ret
 881   *   Array to which query results will be added.
 882   * @param $table
 883   *   Name of the table.
 884   * @param $field
 885   *   Name of the field to change.
 886   * @param $field_new
 887   *   New name for the field (set to the same as $field if you don't want to change the name).
 888   * @param $spec
 889   *   The field specification for the new field.
 890   * @param $new_keys
 891   *   Optional keys and indexes specification to be created on the
 892   *   table along with changing the field. The format is the same as a
 893   *   table specification but without the 'fields' element.
 894   */
 895  function db_change_field(&$ret, $table, $field, $field_new, $spec, $new_keys = array()) {
 896    $ret[] = update_sql('ALTER TABLE {'. $table .'} RENAME "'. $field .'" TO "'. $field .'_old"');
 897    $not_null = isset($spec['not null']) ? $spec['not null'] : FALSE;
 898    unset($spec['not null']);
 899  
 900    if (!array_key_exists('size', $spec)) {
 901      $spec['size'] = 'normal';
 902    }
 903    db_add_field($ret, $table, "$field_new", $spec);
 904  
 905    // We need to type cast the new column to best transfer the data
 906    // db_type_map will return possiblities that are not 'cast-able'
 907    // such as serial - they must be made 'int' instead.
 908    $map =  db_type_map();
 909    $typecast = $map[$spec['type'] .':'. $spec['size']];
 910    if (in_array($typecast, array('serial', 'bigserial', 'numeric'))) {
 911      $typecast = 'int';
 912    }
 913    $ret[] = update_sql('UPDATE {'. $table .'} SET '. $field_new .' = CAST('. $field .'_old AS '. $typecast .')');
 914  
 915    if ($not_null) {
 916      $ret[] = update_sql("ALTER TABLE {". $table ."} ALTER $field_new SET NOT NULL");
 917    }
 918  
 919    db_drop_field($ret, $table, $field .'_old');
 920  
 921    if (isset($new_keys)) {
 922      _db_create_keys($ret, $table, $new_keys);
 923    }
 924  }
 925  
 926  /**
 927   * @} End of "ingroup schemaapi".
 928   */
 929