<?php /** * StatusNet, the distributed open-source microblogging tool * * Database schema utilities * * PHP version 5 * * LICENCE: This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * @category Database * @package StatusNet * @author Evan Prodromou <evan@status.net> * @copyright 2009 StatusNet, Inc. * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0 * @link http://status.net/ */ if (!defined('STATUSNET')) { exit(1); } /** * Class representing the database schema * * A class representing the database schema. Can be used to * manipulate the schema -- especially for plugins and upgrade * utilities. * * @category Database * @package StatusNet * @author Evan Prodromou <evan@status.net> * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0 * @link http://status.net/ */ class Schema { static $_single = null; protected $conn = null; /** * Constructor. Only run once for singleton object. */ protected function __construct() { // XXX: there should be an easier way to do this. $user = new User(); $this->conn = $user->getDatabaseConnection(); $user->free(); unset($user); } /** * Main public entry point. Use this to get * the singleton object. * * @return Schema the (single) Schema object */ static function get() { $type = common_config('db', 'type'); if (empty(self::$_single)) { $schemaClass = ucfirst($type).'Schema'; self::$_single = new $schemaClass(); } return self::$_single; } /** * Gets a ColumnDef object for a single column. * * Throws an exception if the table is not found. * * @param string $table name of the table * @param string $column name of the column * * @return ColumnDef definition of the column or null * if not found. */ public function getColumnDef($table, $column) { $td = $this->getTableDef($table); foreach ($td->columns as $cd) { if ($cd->name == $column) { return $cd; } } return null; } /** * Creates a table with the given names and columns. * * @param string $name Name of the table * @param array $columns Array of ColumnDef objects * for new table. * * @return boolean success flag */ public function createTable($name, $columns) { $uniques = array(); $primary = array(); $indices = array(); $sql = "CREATE TABLE $name (\n"; for ($i = 0; $i < count($columns); $i++) { $cd =& $columns[$i]; if ($i > 0) { $sql .= ",\n"; } $sql .= $this->_columnSql($cd); switch ($cd->key) { case 'UNI': $uniques[] = $cd->name; break; case 'PRI': $primary[] = $cd->name; break; case 'MUL': $indices[] = $cd->name; break; } } if (count($primary) > 0) { // it really should be... $sql .= ",\nconstraint primary key (" . implode(',', $primary) . ")"; } foreach ($uniques as $u) { $sql .= ",\nunique index {$name}_{$u}_idx ($u)"; } foreach ($indices as $i) { $sql .= ",\nindex {$name}_{$i}_idx ($i)"; } $sql .= "); "; $res = $this->conn->query($sql); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Drops a table from the schema * * Throws an exception if the table is not found. * * @param string $name Name of the table to drop * * @return boolean success flag */ public function dropTable($name) { $res = $this->conn->query("DROP TABLE $name"); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Adds an index to a table. * * If no name is provided, a name will be made up based * on the table name and column names. * * Throws an exception on database error, esp. if the table * does not exist. * * @param string $table Name of the table * @param array $columnNames Name of columns to index * @param string $name (Optional) name of the index * * @return boolean success flag */ public function createIndex($table, $columnNames, $name=null) { if (!is_array($columnNames)) { $columnNames = array($columnNames); } if (empty($name)) { $name = "$table_".implode("_", $columnNames)."_idx"; } $res = $this->conn->query("ALTER TABLE $table ". "ADD INDEX $name (". implode(",", $columnNames).")"); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Drops a named index from a table. * * @param string $table name of the table the index is on. * @param string $name name of the index * * @return boolean success flag */ public function dropIndex($table, $name) { $res = $this->conn->query("ALTER TABLE $table DROP INDEX $name"); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Adds a column to a table * * @param string $table name of the table * @param ColumnDef $columndef Definition of the new * column. * * @return boolean success flag */ public function addColumn($table, $columndef) { $sql = "ALTER TABLE $table ADD COLUMN " . $this->_columnSql($columndef); $res = $this->conn->query($sql); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Modifies a column in the schema. * * The name must match an existing column and table. * * @param string $table name of the table * @param ColumnDef $columndef new definition of the column. * * @return boolean success flag */ public function modifyColumn($table, $columndef) { $sql = "ALTER TABLE $table MODIFY COLUMN " . $this->_columnSql($columndef); $res = $this->conn->query($sql); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Drops a column from a table * * The name must match an existing column. * * @param string $table name of the table * @param string $columnName name of the column to drop * * @return boolean success flag */ public function dropColumn($table, $columnName) { $sql = "ALTER TABLE $table DROP COLUMN $columnName"; $res = $this->conn->query($sql); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Ensures that a table exists with the given * name and the given column definitions. * * If the table does not yet exist, it will * create the table. If it does exist, it will * alter the table to match the column definitions. * * @param string $tableName name of the table * @param array $columns array of ColumnDef * objects for the table * * @return boolean success flag */ public function ensureTable($tableName, $columns) { // XXX: DB engine portability -> toilet try { $td = $this->getTableDef($tableName); } catch (Exception $e) { if (preg_match('/no such table/', $e->getMessage())) { return $this->createTable($tableName, $columns); } else { throw $e; } } $cur = $this->_names($td->columns); $new = $this->_names($columns); $toadd = array_diff($new, $cur); $todrop = array_diff($cur, $new); $same = array_intersect($new, $cur); $tomod = array(); foreach ($same as $m) { $curCol = $this->_byName($td->columns, $m); $newCol = $this->_byName($columns, $m); if (!$newCol->equals($curCol)) { $tomod[] = $newCol->name; } } if (count($toadd) + count($todrop) + count($tomod) == 0) { // nothing to do return true; } // For efficiency, we want this all in one // query, instead of using our methods. $phrase = array(); foreach ($toadd as $columnName) { $cd = $this->_byName($columns, $columnName); $phrase[] = 'ADD COLUMN ' . $this->_columnSql($cd); } foreach ($todrop as $columnName) { $phrase[] = 'DROP COLUMN ' . $columnName; } foreach ($tomod as $columnName) { $cd = $this->_byName($columns, $columnName); $phrase[] = 'MODIFY COLUMN ' . $this->_columnSql($cd); } $sql = 'ALTER TABLE ' . $tableName . ' ' . implode(', ', $phrase); $res = $this->conn->query($sql); if (PEAR::isError($res)) { throw new Exception($res->getMessage()); } return true; } /** * Returns the array of names from an array of * ColumnDef objects. * * @param array $cds array of ColumnDef objects * * @return array strings for name values */ private function _names($cds) { $names = array(); foreach ($cds as $cd) { $names[] = $cd->name; } return $names; } /** * Get a ColumnDef from an array matching * name. * * @param array $cds Array of ColumnDef objects * @param string $name Name of the column * * @return ColumnDef matching item or null if no match. */ private function _byName($cds, $name) { foreach ($cds as $cd) { if ($cd->name == $name) { return $cd; } } return null; } /** * Return the proper SQL for creating or * altering a column. * * Appropriate for use in CREATE TABLE or * ALTER TABLE statements. * * @param ColumnDef $cd column to create * * @return string correct SQL for that column */ private function _columnSql($cd) { $sql = "{$cd->name} "; if (!empty($cd->size)) { $sql .= "{$cd->type}({$cd->size}) "; } else { $sql .= "{$cd->type} "; } if (!empty($cd->default)) { $sql .= "default {$cd->default} "; } else { $sql .= ($cd->nullable) ? "null " : "not null "; } if (!empty($cd->auto_increment)) { $sql .= " auto_increment "; } if (!empty($cd->extra)) { $sql .= "{$cd->extra} "; } return $sql; } }