gnu-social/lib/schema.php

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<?php
/**
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* StatusNet, the distributed open-source microblogging tool
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*
* 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
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* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @copyright 2009 StatusNet, Inc.
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
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* @link http://status.net/
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*/
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if (!defined('STATUSNET')) {
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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
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* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @author Brion Vibber <brion@status.net>
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* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
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* @link http://status.net/
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*/
class Schema
{
static $_static = null;
protected $conn = null;
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/**
* Constructor. Only run once for singleton object.
*/
protected function __construct($conn = null)
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{
if (is_null($conn)) {
// XXX: there should be an easier way to do this.
$user = new User();
$conn = $user->getDatabaseConnection();
$user->free();
unset($user);
}
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$this->conn = $conn;
}
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/**
* Main public entry point. Use this to get
* the schema object.
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*
* @return Schema the Schema object for the connection
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*/
static function get($conn = null)
{
if (is_null($conn)) {
$key = 'default';
} else {
$key = md5(serialize($conn->dsn));
}
$type = common_config('db', 'type');
if (empty(self::$_static[$key])) {
$schemaClass = ucfirst($type).'Schema';
self::$_static[$key] = new $schemaClass($conn);
}
return self::$_static[$key];
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}
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/**
* 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 $column name of the column
*
* @return ColumnDef definition of the column or null
* if not found.
*/
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public function getColumnDef($table, $column)
{
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$td = $this->getTableDef($table);
foreach ($td->columns as $cd) {
if ($cd->name == $column) {
return $cd;
}
}
return null;
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}
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/**
* 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, $columns)
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{
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$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 ($cd->key) {
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case 'UNI':
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$uniques[] = $cd->name;
break;
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case 'PRI':
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$primary[] = $cd->name;
break;
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case 'MUL':
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$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);
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
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}
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/**
* Drops a table from the schema
*
* Throws an exception if the table is not found.
*
* @param string $name Name of the table to drop
*
* @return boolean success flag
*/
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public function dropTable($name)
{
$res = $this->conn->query("DROP TABLE $name");
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
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}
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/**
* 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, $name=null)
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{
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if (!is_array($columnNames)) {
$columnNames = array($columnNames);
}
if (empty($name)) {
$name = "{$table}_".implode("_", $columnNames)."_idx";
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}
$res = $this->conn->query("ALTER TABLE $table ".
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"ADD INDEX $name (".
implode(",", $columnNames).")");
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
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}
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/**
* Drops a named index from a table.
*
* @param string $table name of the table the index is on.
* @param string $name name of the index
*
* @return boolean success flag
*/
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public function dropIndex($table, $name)
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{
$res = $this->conn->query("ALTER TABLE $table DROP INDEX $name");
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
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}
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/**
* Adds a column to a table
*
* @param string $table name of the table
* @param ColumnDef $columndef Definition of the new
* column.
*
* @return boolean success flag
*/
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public function addColumn($table, $columndef)
{
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$sql = "ALTER TABLE $table ADD COLUMN " . $this->_columnSql($columndef);
$res = $this->conn->query($sql);
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
}
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/**
* Modifies a column in the schema.
*
* The name must match an existing column and table.
*
* @param string $table name of the table
* @param ColumnDef $columndef new definition of the column.
*
* @return boolean success flag
*/
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public function modifyColumn($table, $columndef)
{
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$sql = "ALTER TABLE $table MODIFY COLUMN " .
$this->_columnSql($columndef);
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$res = $this->conn->query($sql);
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
}
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/**
* Drops a column from a table
*
* The name must match an existing column.
*
* @param string $table name of the table
* @param string $columnName name of the column to drop
*
* @return boolean success flag
*/
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public function dropColumn($table, $columnName)
{
$sql = "ALTER TABLE $table DROP COLUMN $columnName";
$res = $this->conn->query($sql);
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
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}
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/**
* 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, $def)
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{
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// XXX: DB engine portability -> toilet
try {
$old = $this->getTableDef($tableName);
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} catch (Exception $e) {
if (preg_match('/no such table/', $e->getMessage())) {
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return $this->createTable($tableName, $columns);
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} else {
throw $e;
}
}
$cur = array_keys($old['fields']);
$new = array_keys($def['fields']);
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$toadd = array_diff($new, $cur);
$todrop = array_diff($cur, $new);
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$same = array_intersect($new, $cur);
$tomod = array();
// Find which fields have actually changed definition
// in a way that we need to tweak them for this DB type.
foreach ($same as $name) {
$curCol = $old['fields'][$name];
$newCol = $cur['fields'][$name];
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if (!$this->columnsEqual($curCol, $newCol)) {
$tomod[] = $name;
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}
}
if (count($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) {
$this->appendAlterAddColumn($phrase, $columnName,
$def['fields'][$columnName]);
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}
foreach ($todrop as $columnName) {
$this->appendAlterModifyColumn($phrase, $columnName,
$old['fields'][$columnName],
$def['fields'][$columnName]);
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}
foreach ($tomod as $columnName) {
$this->appendAlterDropColumn($phrase, $columnName);
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}
$sql = 'ALTER TABLE ' . $tableName . ' ' . implode(', ', $phrase);
$res = $this->conn->query($sql);
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if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
return true;
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}
/**
* Append phrase(s) to an array of partial ALTER TABLE chunks in order
* to add the given column definition to the table.
*
* @param array $phrase
* @param string $columnName
* @param array $cd
*/
function appendAlterAddColumn(array &$phrase, $columnName, array $cd)
{
$phrase[] = 'ADD COLUMN ' .
$this->quoteIdentifier($columnName) .
' ' .
$this->columnSql($cd);
}
/**
* Append phrase(s) to an array of partial ALTER TABLE chunks in order
* to alter the given column from its old state to a new one.
*
* @param array $phrase
* @param string $columnName
* @param array $old previous column definition as found in DB
* @param array $cd current column definition
*/
function appendAlterModifyColumn(array &$phrase, $columnName, array $old, array $cd)
{
$phrase[] = 'MODIFY COLUMN ' .
$this->quoteIdentifier($columnName) .
' ' .
$this->columnSql($cd);
}
/**
* Append phrase(s) to an array of partial ALTER TABLE chunks in order
* to drop the given column definition from the table.
*
* @param array $phrase
* @param string $columnName
*/
function appendAlterDropColumn(array &$phrase, $columnName)
{
$phrase[] = 'DROP COLUMN ' . $this->quoteIdentifier($columnName);
}
/**
* Quote a db/table/column identifier if necessary.
*
* @param string $name
* @return string
*/
function quoteIdentifier($name)
{
return $name;
}
function quoteDefaultValue($cd)
{
if ($cd['type'] == 'datetime' && $cd['default'] == 'CURRENT_TIMESTAMP') {
return $cd['default'];
} else {
return $this->quoteValue($cd['default']);
}
}
function quoteValue($val)
{
return $this->conn->escape($val);
}
/**
* Check if two column definitions are equivalent.
* The default implementation checks _everything_ but in many cases
* you may be able to discard a bunch of equivalencies.
*
* @param array $a
* @param array $b
* @return boolean
*/
function columnsEqual(array $a, array $b)
{
return !array_diff_assoc($a, $b) && !array_diff_assoc($b, $a);
}
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/**
* Returns the array of names from an array of
* ColumnDef objects.
*
* @param array $cds array of ColumnDef objects
*
* @return array strings for name values
*/
protected function _names($cds)
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{
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$names = array();
foreach ($cds as $cd) {
$names[] = $cd->name;
}
return $names;
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}
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/**
* Get a ColumnDef from an array matching
* name.
*
* @param array $cds Array of ColumnDef objects
* @param string $name Name of the column
*
* @return ColumnDef matching item or null if no match.
*/
protected function _byName($cds, $name)
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{
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foreach ($cds as $cd) {
if ($cd->name == $name) {
return $cd;
}
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}
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return null;
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}
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/**
* 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
*/
function columnSql(array $cd)
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{
$line = array();
$line[] = $this->typeAndSize();
if (isset($cd['default'])) {
$line[] = 'default';
$line[] = $this->quoted($cd['default']);
} else if (!empty($cd['not null'])) {
// Can't have both not null AND default!
$line[] = 'not null';
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}
return implode(' ', $line);
}
/**
*
* @param string $column canonical type name in defs
* @return string native DB type name
*/
function mapType($column)
{
return $column;
}
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function typeAndSize($column)
{
$type = $this->mapType($column);
$lengths = array();
if ($column['type'] == 'numeric') {
if (isset($column['precision'])) {
$lengths[] = $column['precision'];
if (isset($column['scale'])) {
$lengths[] = $column['scale'];
}
}
} else if (isset($column['length'])) {
$lengths[] = $column['length'];
}
if ($lengths) {
return $type . '(' . implode(',', $lengths) . ')';
} else {
return $type;
}
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}
/**
* Map a native type back to an independent type + size
*
* @param string $type
* @return array ($type, $size) -- $size may be null
*/
protected function reverseMapType($type)
{
return array($type, null);
}
/**
* Convert an old-style set of ColumnDef objects into the current
* Drupal-style schema definition array, for backwards compatibility
* with plugins written for 0.9.x.
*
* @param string $tableName
* @param array $defs
* @return array
*/
function oldToNew($tableName, $defs)
{
$table = array();
$prefixes = array(
'tiny',
'small',
'medium',
'big',
);
foreach ($defs as $cd) {
$cd->addToTableDef($table);
$column = array();
$column['type'] = $cd->type;
foreach ($prefixes as $prefix) {
if (substr($cd->type, 0, strlen($prefix)) == $prefix) {
$column['type'] = substr($cd->type, strlen($prefix));
$column['size'] = $prefix;
break;
}
}
if ($cd->size) {
if ($cd->type == 'varchar' || $cd->type == 'char') {
$column['length'] = $cd->size;
}
}
if (!$cd->nullable) {
$column['not null'] = true;
}
if ($cd->autoincrement) {
$column['type'] = 'serial';
}
if ($cd->default) {
$column['default'] = $cd->default;
}
$table['fields'][$cd->name] = $column;
if ($cd->key == 'PRI') {
// If multiple columns are defined as primary key,
// we'll pile them on in sequence.
if (!isset($table['primary key'])) {
$table['primary key'] = array();
}
$table['primary key'][] = $cd->name;
} else if ($cd->key == 'MUL') {
// Individual multiple-value indexes are only per-column
// using the old ColumnDef syntax.
$idx = "{$tableName}_{$cd->name}_idx";
$table['indexes'][$idx] = array($cd->name);
} else if ($cd->key == 'UNI') {
// Individual unique-value indexes are only per-column
// using the old ColumnDef syntax.
$idx = "{$tableName}_{$cd->name}_idx";
$table['unique keys'][$idx] = array($cd->name);
}
}
return $table;
}
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function isNumericType($type)
{
$type = strtolower($type);
$known = array('int', 'serial', 'numeric');
return in_array($type, $known);
}
/**
* Pull info from the query into a fun-fun array of dooooom
*
* @param string $sql
* @return array of arrays
*/
protected function fetchQueryData($sql)
{
$res = $this->conn->query($sql);
if (PEAR::isError($res)) {
throw new Exception($res->getMessage());
}
$out = array();
$row = array();
while ($res->fetchInto($row, DB_FETCHMODE_ASSOC)) {
$out[] = $row;
}
$res->free();
return $out;
}
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}
class SchemaTableMissingException extends Exception
{
// no-op
}