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 $name " . $this->buildIndexList($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, 'buildIndexItem'), $def)) . ')';
260 function buildIndexItem($def)
262 if (is_array($def)) {
263 list($name, $size) = $def;
264 return $this->quoteIdentifier($name) . '(' . intval($size) . ')';
266 return $this->quoteIdentifier($def);
270 * Drops a table from the schema
272 * Throws an exception if the table is not found.
274 * @param string $name Name of the table to drop
276 * @return boolean success flag
279 public function dropTable($name)
281 $res = $this->conn->query("DROP TABLE $name");
283 if (PEAR::isError($res)) {
284 throw new Exception($res->getMessage());
291 * Adds an index to a table.
293 * If no name is provided, a name will be made up based
294 * on the table name and column names.
296 * Throws an exception on database error, esp. if the table
299 * @param string $table Name of the table
300 * @param array $columnNames Name of columns to index
301 * @param string $name (Optional) name of the index
303 * @return boolean success flag
306 public function createIndex($table, $columnNames, $name=null)
308 if (!is_array($columnNames)) {
309 $columnNames = array($columnNames);
313 $name = "{$table}_".implode("_", $columnNames)."_idx";
316 $res = $this->conn->query("ALTER TABLE $table ".
318 implode(",", $columnNames).")");
320 if (PEAR::isError($res)) {
321 throw new Exception($res->getMessage());
328 * Drops a named index from a table.
330 * @param string $table name of the table the index is on.
331 * @param string $name name of the index
333 * @return boolean success flag
336 public function dropIndex($table, $name)
338 $res = $this->conn->query("ALTER TABLE $table DROP INDEX $name");
340 if (PEAR::isError($res)) {
341 throw new Exception($res->getMessage());
348 * Adds a column to a table
350 * @param string $table name of the table
351 * @param ColumnDef $columndef Definition of the new
354 * @return boolean success flag
357 public function addColumn($table, $columndef)
359 $sql = "ALTER TABLE $table ADD COLUMN " . $this->_columnSql($columndef);
361 $res = $this->conn->query($sql);
363 if (PEAR::isError($res)) {
364 throw new Exception($res->getMessage());
371 * Modifies a column in the schema.
373 * The name must match an existing column and table.
375 * @param string $table name of the table
376 * @param ColumnDef $columndef new definition of the column.
378 * @return boolean success flag
381 public function modifyColumn($table, $columndef)
383 $sql = "ALTER TABLE $table MODIFY COLUMN " .
384 $this->_columnSql($columndef);
386 $res = $this->conn->query($sql);
388 if (PEAR::isError($res)) {
389 throw new Exception($res->getMessage());
396 * Drops a column from a table
398 * The name must match an existing column.
400 * @param string $table name of the table
401 * @param string $columnName name of the column to drop
403 * @return boolean success flag
406 public function dropColumn($table, $columnName)
408 $sql = "ALTER TABLE $table DROP COLUMN $columnName";
410 $res = $this->conn->query($sql);
412 if (PEAR::isError($res)) {
413 throw new Exception($res->getMessage());
420 * Ensures that a table exists with the given
421 * name and the given column definitions.
423 * If the table does not yet exist, it will
424 * create the table. If it does exist, it will
425 * alter the table to match the column definitions.
427 * @param string $tableName name of the table
428 * @param array $def Table definition array
430 * @return boolean success flag
433 public function ensureTable($tableName, $def)
435 $statements = $this->buildEnsureTable($tableName, $def);
436 return $this->runSqlSet($statements);
440 * Run a given set of SQL commands on the connection in sequence.
443 * @fixme if multiple statements, wrap in a transaction?
444 * @param array $statements
445 * @return boolean success flag
447 function runSqlSet(array $statements)
450 foreach ($statements as $sql) {
451 $res = $this->conn->query($sql);
453 if (PEAR::isError($res)) {
454 throw new Exception($res->getMessage());
461 * Check a table's status, and if needed build a set
462 * of SQL statements which change it to be consistent
463 * with the given table definition.
465 * If the table does not yet exist, statements will
466 * be returned to create the table. If it does exist,
467 * statements will be returned to alter the table to
468 * match the column definitions.
470 * @param string $tableName name of the table
471 * @param array $columns array of ColumnDef
472 * objects for the table
474 * @return array of SQL statements
477 function buildEnsureTable($tableName, $def)
480 $old = $this->getTableDef($tableName);
481 } catch (Exception $e) {
482 // @fixme this is a terrible check :D
483 if (preg_match('/no such table/', $e->getMessage())) {
484 return $this->buildCreateTable($tableName, $def);
490 // @fixme check if not present
491 $fields = $this->diffArrays($old['fields'], $def['fields'], array($this, 'columnsEqual'));
492 $uniques = $this->diffArrays($old['unique keys'], $def['unique keys']);
493 $indexes = $this->diffArrays($old['indexes'], $def['indexes']);
496 if (count($toadd) + count($todrop) + count($tomod) == 0) {
502 // For efficiency, we want this all in one
503 // query, instead of using our methods.
507 foreach ($uniques['del'] + $uniques['mod'] as $keyName) {
508 $this->appendAlterDropUnique($phrase, $keyName);
511 foreach ($fields['add'] as $columnName) {
512 $this->appendAlterAddColumn($phrase, $columnName,
513 $def['fields'][$columnName]);
516 foreach ($fields['mod'] as $columnName) {
517 $this->appendAlterModifyColumn($phrase, $columnName,
518 $old['fields'][$columnName],
519 $def['fields'][$columnName]);
522 foreach ($fields['del'] as $columnName) {
523 $this->appendAlterDropColumn($phrase, $columnName);
526 foreach ($uniques['mod'] + $uniques['add'] as $keyName) {
527 $this->appendAlterAddUnique($phrase, $keyName, $def['unique keys'][$keyName]);
530 $sql = 'ALTER TABLE ' . $tableName . ' ' . implode(",\n", $phrase);
535 function diffArrays($old, $new, $compareCallback=null)
538 $oldKeys = array_keys($old ? $old : array());
539 $newKeys = array_keys($new ? $new : array());
541 $toadd = array_diff($newKeys, $oldKeys);
542 $todrop = array_diff($oldKeys, $newKeys);
543 $same = array_intersect($newKeys, $oldKeys);
547 // Find which fields have actually changed definition
548 // in a way that we need to tweak them for this DB type.
549 foreach ($same as $name) {
550 if ($compareCallback) {
551 $same = call_user_func($compareCallback, $old[$name], $new[$name]);
553 $same = ($old[$name] != $new[$name]);
561 return array('add' => $toadd,
568 * Append phrase(s) to an array of partial ALTER TABLE chunks in order
569 * to add the given column definition to the table.
571 * @param array $phrase
572 * @param string $columnName
575 function appendAlterAddColumn(array &$phrase, $columnName, array $cd)
577 $phrase[] = 'ADD COLUMN ' .
578 $this->quoteIdentifier($columnName) .
580 $this->columnSql($cd);
584 * Append phrase(s) to an array of partial ALTER TABLE chunks in order
585 * to alter the given column from its old state to a new one.
587 * @param array $phrase
588 * @param string $columnName
589 * @param array $old previous column definition as found in DB
590 * @param array $cd current column definition
592 function appendAlterModifyColumn(array &$phrase, $columnName, array $old, array $cd)
594 $phrase[] = 'MODIFY COLUMN ' .
595 $this->quoteIdentifier($columnName) .
597 $this->columnSql($cd);
601 * Append phrase(s) to an array of partial ALTER TABLE chunks in order
602 * to drop the given column definition from the table.
604 * @param array $phrase
605 * @param string $columnName
607 function appendAlterDropColumn(array &$phrase, $columnName)
609 $phrase[] = 'DROP COLUMN ' . $this->quoteIdentifier($columnName);
612 function appendAlterAddUnique(array &$phrase, $keyName, array $def)
616 $this->appendUniqueKeyDef($sql, $keyName, $def);
617 $phrase[] = implode(' ', $sql);'ADD CONSTRAINT ' . $keyName;
620 function appendAlterDropUnique(array &$phrase, $keyName)
622 $phrase[] = 'DROP CONSTRAINT ' . $keyName;
626 * Quote a db/table/column identifier if necessary.
628 * @param string $name
631 function quoteIdentifier($name)
636 function quoteDefaultValue($cd)
638 if ($cd['type'] == 'datetime' && $cd['default'] == 'CURRENT_TIMESTAMP') {
639 return $cd['default'];
641 return $this->quoteValue($cd['default']);
645 function quoteValue($val)
647 if (is_int($val) || is_float($val) || is_double($val)) {
650 return '"' . $this->conn->escapeSimple($val) . '"';
655 * Check if two column definitions are equivalent.
656 * The default implementation checks _everything_ but in many cases
657 * you may be able to discard a bunch of equivalencies.
663 function columnsEqual(array $a, array $b)
665 return !array_diff_assoc($a, $b) && !array_diff_assoc($b, $a);
669 * Returns the array of names from an array of
672 * @param array $cds array of ColumnDef objects
674 * @return array strings for name values
677 protected function _names($cds)
681 foreach ($cds as $cd) {
682 $names[] = $cd->name;
689 * Get a ColumnDef from an array matching
692 * @param array $cds Array of ColumnDef objects
693 * @param string $name Name of the column
695 * @return ColumnDef matching item or null if no match.
698 protected function _byName($cds, $name)
700 foreach ($cds as $cd) {
701 if ($cd->name == $name) {
710 * Return the proper SQL for creating or
713 * Appropriate for use in CREATE TABLE or
714 * ALTER TABLE statements.
716 * @param ColumnDef $cd column to create
718 * @return string correct SQL for that column
721 function columnSql(array $cd)
724 $line[] = $this->typeAndSize($cd);
726 if (isset($cd['default'])) {
728 $line[] = $this->quoteDefaultValue($cd);
729 } else if (!empty($cd['not null'])) {
730 // Can't have both not null AND default!
731 $line[] = 'not null';
734 return implode(' ', $line);
739 * @param string $column canonical type name in defs
740 * @return string native DB type name
742 function mapType($column)
747 function typeAndSize($column)
749 $type = $this->mapType($column);
752 if ($column['type'] == 'numeric') {
753 if (isset($column['precision'])) {
754 $lengths[] = $column['precision'];
755 if (isset($column['scale'])) {
756 $lengths[] = $column['scale'];
759 } else if (isset($column['length'])) {
760 $lengths[] = $column['length'];
764 return $type . '(' . implode(',', $lengths) . ')';
771 * Map a native type back to an independent type + size
773 * @param string $type
774 * @return array ($type, $size) -- $size may be null
776 protected function reverseMapType($type)
778 return array($type, null);
782 * Convert an old-style set of ColumnDef objects into the current
783 * Drupal-style schema definition array, for backwards compatibility
784 * with plugins written for 0.9.x.
786 * @param string $tableName
790 function oldToNew($tableName, $defs)
799 foreach ($defs as $cd) {
800 $cd->addToTableDef($table);
802 $column['type'] = $cd->type;
803 foreach ($prefixes as $prefix) {
804 if (substr($cd->type, 0, strlen($prefix)) == $prefix) {
805 $column['type'] = substr($cd->type, strlen($prefix));
806 $column['size'] = $prefix;
812 if ($cd->type == 'varchar' || $cd->type == 'char') {
813 $column['length'] = $cd->size;
816 if (!$cd->nullable) {
817 $column['not null'] = true;
819 if ($cd->autoincrement) {
820 $column['type'] = 'serial';
823 $column['default'] = $cd->default;
825 $table['fields'][$cd->name] = $column;
827 if ($cd->key == 'PRI') {
828 // If multiple columns are defined as primary key,
829 // we'll pile them on in sequence.
830 if (!isset($table['primary key'])) {
831 $table['primary key'] = array();
833 $table['primary key'][] = $cd->name;
834 } else if ($cd->key == 'MUL') {
835 // Individual multiple-value indexes are only per-column
836 // using the old ColumnDef syntax.
837 $idx = "{$tableName}_{$cd->name}_idx";
838 $table['indexes'][$idx] = array($cd->name);
839 } else if ($cd->key == 'UNI') {
840 // Individual unique-value indexes are only per-column
841 // using the old ColumnDef syntax.
842 $idx = "{$tableName}_{$cd->name}_idx";
843 $table['unique keys'][$idx] = array($cd->name);
850 function isNumericType($type)
852 $type = strtolower($type);
853 $known = array('int', 'serial', 'numeric');
854 return in_array($type, $known);
858 * Pull info from the query into a fun-fun array of dooooom
861 * @return array of arrays
863 protected function fetchQueryData($sql)
865 $res = $this->conn->query($sql);
866 if (PEAR::isError($res)) {
867 throw new Exception($res->getMessage());
872 while ($res->fetchInto($row, DB_FETCHMODE_ASSOC)) {
882 class SchemaTableMissingException extends Exception