3 * StatusNet, the distributed open-source microblogging tool
5 * Database schema utilities
9 * LICENCE: This program is free software: you can redistribute it and/or modify
10 * it under the terms of the GNU Affero General Public License as published by
11 * the Free Software Foundation, either version 3 of the License, or
12 * (at your option) any later version.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU Affero General Public License for more details.
19 * You should have received a copy of the GNU Affero General Public License
20 * along with this program. If not, see <http://www.gnu.org/licenses/>.
24 * @author Evan Prodromou <evan@status.net>
25 * @copyright 2009 StatusNet, Inc.
26 * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
27 * @link http://status.net/
30 if (!defined('STATUSNET')) {
35 * Class representing the database schema
37 * A class representing the database schema. Can be used to
38 * manipulate the schema -- especially for plugins and upgrade
43 * @author Evan Prodromou <evan@status.net>
44 * @author Brion Vibber <brion@status.net>
45 * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
46 * @link http://status.net/
51 static $_static = null;
52 protected $conn = null;
55 * Constructor. Only run once for singleton object.
58 protected function __construct($conn = null)
61 // XXX: there should be an easier way to do this.
63 $conn = $user->getDatabaseConnection();
72 * Main public entry point. Use this to get
75 * @return Schema the Schema object for the connection
78 static function get($conn = null)
83 $key = md5(serialize($conn->dsn));
86 $type = common_config('db', 'type');
87 if (empty(self::$_static[$key])) {
88 $schemaClass = ucfirst($type).'Schema';
89 self::$_static[$key] = new $schemaClass($conn);
91 return self::$_static[$key];
95 * Gets a ColumnDef object for a single column.
97 * Throws an exception if the table is not found.
99 * @param string $table name of the table
100 * @param string $column name of the column
102 * @return ColumnDef definition of the column or null
106 public function getColumnDef($table, $column)
108 $td = $this->getTableDef($table);
110 foreach ($td->columns as $cd) {
111 if ($cd->name == $column) {
120 * Creates a table with the given names and columns.
122 * @param string $name Name of the table
123 * @param array $columns Array of ColumnDef objects
126 * @return boolean success flag
129 public function createTable($name, $columns)
131 $statements = $this->buildCreateTable($tableName, $def);
132 return $this->runSqlSet($statements);
136 * Build a set of SQL statements to create a table with the given
139 * @param string $name Name of the table
140 * @param array $def Table definition array
142 * @return boolean success flag
144 public function buildCreateTable($name, $def)
148 foreach ($def['fields'] as $col => $colDef) {
149 $this->appendColumnDef($sql, $col, $colDef);
152 // Primary and unique keys are constraints, so go within
153 // the CREATE TABLE statement normally.
154 if (!empty($def['primary key'])) {
155 $this->appendPrimaryKeyDef($sql, $def['primary key']);
158 if (!empty($def['unique keys'])) {
159 foreach ($def['unique keys'] as $col => $colDef) {
160 $this->appendUniqueKeyDef($sql, $col, $colDef);
164 // Multi-value indexes are advisory and for best portability
165 // should be created as separate statements.
166 $statements = array();
167 $statements[] = $this->startCreateTable($name, $def) . "\n" .
168 implode($sql, ",\n") . "\n" .
169 $this->endCreateTable($name, $def);
170 if (!empty($def['indexes'])) {
171 foreach ($def['indexes'] as $col => $colDef) {
172 $this->appendCreateIndex($statements, $name, $col, $colDef);
180 * Set up a 'create table' SQL statement.
182 * @param string $name table name
183 * @param array $def table definition
186 function startCreateTable($name, array $def)
188 return 'CREATE TABLE ' . $this->quoteIdentifier($name) . ' (';
192 * Close out a 'create table' SQL statement.
194 * @param string $name table name
195 * @param array $def table definition
198 function endCreateTable($name, array $def)
204 * Append an SQL fragment with a column definition in a CREATE TABLE statement.
207 * @param string $name
210 function appendColumnDef(array &$sql, $name, array $def)
212 $sql[] = "$name " . $this->columnSql($def);
216 * Append an SQL fragment with a constraint definition for a primary
217 * key in a CREATE TABLE statement.
222 function appendPrimaryKeyDef(array &$sql, array $def)
224 $sql[] = "PRIMARY KEY " . $this->buildIndexList($def);
228 * Append an SQL fragment with a constraint definition for a primary
229 * key in a CREATE TABLE statement.
232 * @param string $name
235 function appendUniqueKeyDef(array &$sql, $name, array $def)
237 $sql[] = "UNIQUE $key " . $this->buildIndexList($def);
241 * Append an SQL statement with an index definition for an advisory
242 * index over one or more columns on a table.
244 * @param array $statements
245 * @param string $table
246 * @param string $name
249 function appendCreateIndex(array &$statements, $table, $name, array $def)
251 $statements[] = "CREATE INDEX $name ON $table " . $this->buildIndexList($def);
254 function buildIndexList(array $def)
257 return '(' . implode(',', array_map(array($this, 'quoteIdentifier'), $def)) . ')';
261 * Drops a table from the schema
263 * Throws an exception if the table is not found.
265 * @param string $name Name of the table to drop
267 * @return boolean success flag
270 public function dropTable($name)
272 $res = $this->conn->query("DROP TABLE $name");
274 if (PEAR::isError($res)) {
275 throw new Exception($res->getMessage());
282 * Adds an index to a table.
284 * If no name is provided, a name will be made up based
285 * on the table name and column names.
287 * Throws an exception on database error, esp. if the table
290 * @param string $table Name of the table
291 * @param array $columnNames Name of columns to index
292 * @param string $name (Optional) name of the index
294 * @return boolean success flag
297 public function createIndex($table, $columnNames, $name=null)
299 if (!is_array($columnNames)) {
300 $columnNames = array($columnNames);
304 $name = "{$table}_".implode("_", $columnNames)."_idx";
307 $res = $this->conn->query("ALTER TABLE $table ".
309 implode(",", $columnNames).")");
311 if (PEAR::isError($res)) {
312 throw new Exception($res->getMessage());
319 * Drops a named index from a table.
321 * @param string $table name of the table the index is on.
322 * @param string $name name of the index
324 * @return boolean success flag
327 public function dropIndex($table, $name)
329 $res = $this->conn->query("ALTER TABLE $table DROP INDEX $name");
331 if (PEAR::isError($res)) {
332 throw new Exception($res->getMessage());
339 * Adds a column to a table
341 * @param string $table name of the table
342 * @param ColumnDef $columndef Definition of the new
345 * @return boolean success flag
348 public function addColumn($table, $columndef)
350 $sql = "ALTER TABLE $table ADD COLUMN " . $this->_columnSql($columndef);
352 $res = $this->conn->query($sql);
354 if (PEAR::isError($res)) {
355 throw new Exception($res->getMessage());
362 * Modifies a column in the schema.
364 * The name must match an existing column and table.
366 * @param string $table name of the table
367 * @param ColumnDef $columndef new definition of the column.
369 * @return boolean success flag
372 public function modifyColumn($table, $columndef)
374 $sql = "ALTER TABLE $table MODIFY COLUMN " .
375 $this->_columnSql($columndef);
377 $res = $this->conn->query($sql);
379 if (PEAR::isError($res)) {
380 throw new Exception($res->getMessage());
387 * Drops a column from a table
389 * The name must match an existing column.
391 * @param string $table name of the table
392 * @param string $columnName name of the column to drop
394 * @return boolean success flag
397 public function dropColumn($table, $columnName)
399 $sql = "ALTER TABLE $table DROP COLUMN $columnName";
401 $res = $this->conn->query($sql);
403 if (PEAR::isError($res)) {
404 throw new Exception($res->getMessage());
411 * Ensures that a table exists with the given
412 * name and the given column definitions.
414 * If the table does not yet exist, it will
415 * create the table. If it does exist, it will
416 * alter the table to match the column definitions.
418 * @param string $tableName name of the table
419 * @param array $def Table definition array
421 * @return boolean success flag
424 public function ensureTable($tableName, $def)
426 $statements = $this->buildEnsureTable($tableName, $def);
427 return $this->runSqlSet($statements);
431 * Run a given set of SQL commands on the connection in sequence.
434 * @fixme if multiple statements, wrap in a transaction?
435 * @param array $statements
436 * @return boolean success flag
438 function runSqlSet(array $statements)
441 foreach ($statements as $sql) {
442 $res = $this->conn->query($sql);
444 if (PEAR::isError($res)) {
445 throw new Exception($res->getMessage());
452 * Check a table's status, and if needed build a set
453 * of SQL statements which change it to be consistent
454 * with the given table definition.
456 * If the table does not yet exist, statements will
457 * be returned to create the table. If it does exist,
458 * statements will be returned to alter the table to
459 * match the column definitions.
461 * @param string $tableName name of the table
462 * @param array $columns array of ColumnDef
463 * objects for the table
465 * @return array of SQL statements
468 function buildEnsureTable($tableName, $def)
471 $old = $this->getTableDef($tableName);
472 } catch (Exception $e) {
473 // @fixme this is a terrible check :D
474 if (preg_match('/no such table/', $e->getMessage())) {
475 return $this->buildCreateTable($tableName, $def);
481 $cur = array_keys($old['fields']);
482 $new = array_keys($def['fields']);
484 $toadd = array_diff($new, $cur);
485 $todrop = array_diff($cur, $new);
486 $same = array_intersect($new, $cur);
489 // Find which fields have actually changed definition
490 // in a way that we need to tweak them for this DB type.
491 foreach ($same as $name) {
492 $curCol = $old['fields'][$name];
493 $newCol = $cur['fields'][$name];
495 if (!$this->columnsEqual($curCol, $newCol)) {
500 if (count($toadd) + count($todrop) + count($tomod) == 0) {
505 // For efficiency, we want this all in one
506 // query, instead of using our methods.
510 foreach ($toadd as $columnName) {
511 $this->appendAlterAddColumn($phrase, $columnName,
512 $def['fields'][$columnName]);
515 foreach ($todrop as $columnName) {
516 $this->appendAlterModifyColumn($phrase, $columnName,
517 $old['fields'][$columnName],
518 $def['fields'][$columnName]);
521 foreach ($tomod as $columnName) {
522 $this->appendAlterDropColumn($phrase, $columnName);
525 $sql = 'ALTER TABLE ' . $tableName . ' ' . implode(', ', $phrase);
527 $res = $this->conn->query($sql);
529 if (PEAR::isError($res)) {
530 throw new Exception($res->getMessage());
537 * Append phrase(s) to an array of partial ALTER TABLE chunks in order
538 * to add the given column definition to the table.
540 * @param array $phrase
541 * @param string $columnName
544 function appendAlterAddColumn(array &$phrase, $columnName, array $cd)
546 $phrase[] = 'ADD COLUMN ' .
547 $this->quoteIdentifier($columnName) .
549 $this->columnSql($cd);
553 * Append phrase(s) to an array of partial ALTER TABLE chunks in order
554 * to alter the given column from its old state to a new one.
556 * @param array $phrase
557 * @param string $columnName
558 * @param array $old previous column definition as found in DB
559 * @param array $cd current column definition
561 function appendAlterModifyColumn(array &$phrase, $columnName, array $old, array $cd)
563 $phrase[] = 'MODIFY COLUMN ' .
564 $this->quoteIdentifier($columnName) .
566 $this->columnSql($cd);
570 * Append phrase(s) to an array of partial ALTER TABLE chunks in order
571 * to drop the given column definition from the table.
573 * @param array $phrase
574 * @param string $columnName
576 function appendAlterDropColumn(array &$phrase, $columnName)
578 $phrase[] = 'DROP COLUMN ' . $this->quoteIdentifier($columnName);
582 * Quote a db/table/column identifier if necessary.
584 * @param string $name
587 function quoteIdentifier($name)
592 function quoteDefaultValue($cd)
594 if ($cd['type'] == 'datetime' && $cd['default'] == 'CURRENT_TIMESTAMP') {
595 return $cd['default'];
597 return $this->quoteValue($cd['default']);
601 function quoteValue($val)
603 if (is_int($val) || is_float($val) || is_double($val)) {
606 return '"' . $this->conn->escapeSimple($val) . '"';
611 * Check if two column definitions are equivalent.
612 * The default implementation checks _everything_ but in many cases
613 * you may be able to discard a bunch of equivalencies.
619 function columnsEqual(array $a, array $b)
621 return !array_diff_assoc($a, $b) && !array_diff_assoc($b, $a);
625 * Returns the array of names from an array of
628 * @param array $cds array of ColumnDef objects
630 * @return array strings for name values
633 protected function _names($cds)
637 foreach ($cds as $cd) {
638 $names[] = $cd->name;
645 * Get a ColumnDef from an array matching
648 * @param array $cds Array of ColumnDef objects
649 * @param string $name Name of the column
651 * @return ColumnDef matching item or null if no match.
654 protected function _byName($cds, $name)
656 foreach ($cds as $cd) {
657 if ($cd->name == $name) {
666 * Return the proper SQL for creating or
669 * Appropriate for use in CREATE TABLE or
670 * ALTER TABLE statements.
672 * @param ColumnDef $cd column to create
674 * @return string correct SQL for that column
677 function columnSql(array $cd)
680 $line[] = $this->typeAndSize($cd);
682 if (isset($cd['default'])) {
684 $line[] = $this->quoteDefaultValue($cd);
685 } else if (!empty($cd['not null'])) {
686 // Can't have both not null AND default!
687 $line[] = 'not null';
690 return implode(' ', $line);
695 * @param string $column canonical type name in defs
696 * @return string native DB type name
698 function mapType($column)
703 function typeAndSize($column)
705 $type = $this->mapType($column);
708 if ($column['type'] == 'numeric') {
709 if (isset($column['precision'])) {
710 $lengths[] = $column['precision'];
711 if (isset($column['scale'])) {
712 $lengths[] = $column['scale'];
715 } else if (isset($column['length'])) {
716 $lengths[] = $column['length'];
720 return $type . '(' . implode(',', $lengths) . ')';
727 * Map a native type back to an independent type + size
729 * @param string $type
730 * @return array ($type, $size) -- $size may be null
732 protected function reverseMapType($type)
734 return array($type, null);
738 * Convert an old-style set of ColumnDef objects into the current
739 * Drupal-style schema definition array, for backwards compatibility
740 * with plugins written for 0.9.x.
742 * @param string $tableName
746 function oldToNew($tableName, $defs)
755 foreach ($defs as $cd) {
756 $cd->addToTableDef($table);
758 $column['type'] = $cd->type;
759 foreach ($prefixes as $prefix) {
760 if (substr($cd->type, 0, strlen($prefix)) == $prefix) {
761 $column['type'] = substr($cd->type, strlen($prefix));
762 $column['size'] = $prefix;
768 if ($cd->type == 'varchar' || $cd->type == 'char') {
769 $column['length'] = $cd->size;
772 if (!$cd->nullable) {
773 $column['not null'] = true;
775 if ($cd->autoincrement) {
776 $column['type'] = 'serial';
779 $column['default'] = $cd->default;
781 $table['fields'][$cd->name] = $column;
783 if ($cd->key == 'PRI') {
784 // If multiple columns are defined as primary key,
785 // we'll pile them on in sequence.
786 if (!isset($table['primary key'])) {
787 $table['primary key'] = array();
789 $table['primary key'][] = $cd->name;
790 } else if ($cd->key == 'MUL') {
791 // Individual multiple-value indexes are only per-column
792 // using the old ColumnDef syntax.
793 $idx = "{$tableName}_{$cd->name}_idx";
794 $table['indexes'][$idx] = array($cd->name);
795 } else if ($cd->key == 'UNI') {
796 // Individual unique-value indexes are only per-column
797 // using the old ColumnDef syntax.
798 $idx = "{$tableName}_{$cd->name}_idx";
799 $table['unique keys'][$idx] = array($cd->name);
806 function isNumericType($type)
808 $type = strtolower($type);
809 $known = array('int', 'serial', 'numeric');
810 return in_array($type, $known);
814 * Pull info from the query into a fun-fun array of dooooom
817 * @return array of arrays
819 protected function fetchQueryData($sql)
821 $res = $this->conn->query($sql);
822 if (PEAR::isError($res)) {
823 throw new Exception($res->getMessage());
828 while ($res->fetchInto($row, DB_FETCHMODE_ASSOC)) {
838 class SchemaTableMissingException extends Exception