gnu-social/lib/mysqlschema.php

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<?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 MysqlSchema extends Schema
{
static $_single = null;
protected $conn = null;
/**
* Main public entry point. Use this to get
* the singleton object.
*
* @return Schema the (single) Schema object
*/
static function get()
{
if (empty(self::$_single)) {
self::$_single = new Schema();
}
return self::$_single;
}
/**
* Returns a TableDef object for the table
* in the schema with the given name.
*
* Throws an exception if the table is not found.
*
* @param string $table Name of the table to get
*
* @return TableDef tabledef for that table.
* @throws SchemaTableMissingException
*/
public function getTableDef($table)
{
$def = array();
$hasKeys = false;
// Pull column data from INFORMATION_SCHEMA
$columns = $this->fetchMetaInfo($table, 'COLUMNS', 'ORDINAL_POSITION');
if (count($columns) == 0) {
throw new SchemaTableMissingException("No such table: $table");
}
foreach ($columns as $row) {
$name = $row['COLUMN_NAME'];
$field = array();
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// warning -- 'unsigned' attr on numbers isn't given in DATA_TYPE and friends.
// It is stuck in on COLUMN_TYPE though (eg 'bigint(20) unsigned')
$field['type'] = $type = $row['DATA_TYPE'];
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if ($type == 'char' || $type == 'varchar') {
if ($row['CHARACTER_MAXIMUM_LENGTH'] !== null) {
$field['length'] = intval($row['CHARACTER_MAXIMUM_LENGTH']);
}
}
if ($type == 'decimal') {
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// Other int types may report these values, but they're irrelevant.
// Just ignore them!
if ($row['NUMERIC_PRECISION'] !== null) {
$field['precision'] = intval($row['NUMERIC_PRECISION']);
}
if ($row['NUMERIC_SCALE'] !== null) {
$field['scale'] = intval($row['NUMERIC_SCALE']);
}
}
if ($row['IS_NULLABLE'] == 'NO') {
$field['not null'] = true;
}
if ($row['COLUMN_DEFAULT'] !== null) {
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// Hack for timestamp cols
if ($type == 'timestamp' && $row['COLUMN_DEFAULT'] == 'CURRENT_TIMESTAMP') {
// skip
} else {
$field['default'] = $row['COLUMN_DEFAULT'];
if ($this->isNumericType($type)) {
$field['default'] = intval($field['default']);
}
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}
}
if ($row['COLUMN_KEY'] !== null) {
// We'll need to look up key info...
$hasKeys = true;
}
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if ($row['COLUMN_COMMENT'] !== null && $row['COLUMN_COMMENT'] != '') {
$field['description'] = $row['COLUMN_COMMENT'];
}
$extra = $row['EXTRA'];
if ($extra) {
if (preg_match('/(^|\s)auto_increment(\s|$)/i', $extra)) {
$field['auto_increment'] = true;
}
// $row['EXTRA'] may contain 'on update CURRENT_TIMESTAMP'
// ^ ...... how to specify?
}
if ($row['CHARACTER_SET_NAME'] !== null) {
// @fixme check against defaults?
//$def['charset'] = $row['CHARACTER_SET_NAME'];
//$def['collate'] = $row['COLLATION_NAME'];
}
$def['fields'][$name] = $field;
}
if ($hasKeys) {
// INFORMATION_SCHEMA's CONSTRAINTS and KEY_COLUMN_USAGE tables give
// good info on primary and unique keys but don't list ANY info on
// multi-value keys, which is lame-o. Sigh.
//
// Let's go old school and use SHOW INDEX :D
//
$keyInfo = $this->fetchIndexInfo($table);
$keys = array();
foreach ($keyInfo as $row) {
$name = $row['Key_name'];
$column = $row['Column_name'];
if (!isset($keys[$name])) {
$keys[$name] = array();
}
$keys[$name][] = $column;
if ($name == 'PRIMARY') {
$type = 'primary key';
} else if ($row['Non_unique'] == 0) {
$type = 'unique keys';
} else if ($row['Index_type'] == 'FULLTEXT') {
$type = 'fulltext indexes';
} else {
$type = 'indexes';
}
$keyTypes[$name] = $type;
}
foreach ($keyTypes as $name => $type) {
if ($type == 'primary key') {
// there can be only one
$def[$type] = $keys[$name];
} else {
$def[$type][$name] = $keys[$name];
}
}
}
return $def;
}
/**
* Pull the given table properties from INFORMATION_SCHEMA.
* Most of the good stuff is MySQL extensions.
*
* @return array
* @throws Exception if table info can't be looked up
*/
function getTableProperties($table, $props)
{
$data = $this->fetchMetaInfo($table, 'TABLES');
if ($data) {
return $data[0];
} else {
throw new SchemaTableMissingException("No such table: $table");
}
}
/**
* Pull some INFORMATION.SCHEMA data for the given table.
*
* @param string $table
* @return array of arrays
*/
function fetchMetaInfo($table, $infoTable, $orderBy=null)
{
$query = "SELECT * FROM INFORMATION_SCHEMA.%s " .
"WHERE TABLE_SCHEMA='%s' AND TABLE_NAME='%s'";
$schema = $this->conn->dsn['database'];
$sql = sprintf($query, $infoTable, $schema, $table);
if ($orderBy) {
$sql .= ' ORDER BY ' . $orderBy;
}
return $this->fetchQueryData($sql);
}
/**
* Pull 'SHOW INDEX' data for the given table.
*
* @param string $table
* @return array of arrays
*/
function fetchIndexInfo($table)
{
$query = "SHOW INDEX FROM `%s`";
$sql = sprintf($query, $table);
return $this->fetchQueryData($sql);
}
/**
* Close out a 'create table' SQL statement.
*
* @param string $name
* @param array $def
* @return string;
*
* @fixme ENGINE may need to be set differently in some cases,
* such as to support fulltext index.
*/
function endCreateTable($name, array $def)
{
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$engine = $this->preferredEngine($def);
return ") ENGINE=$engine CHARACTER SET utf8 COLLATE utf8_bin";
}
function preferredEngine($def)
{
if (!empty($def['fulltext indexes'])) {
return 'MyISAM';
}
return 'InnoDB';
}
/**
* Get the unique index key name for a given column on this table
*/
function _uniqueKey($tableName, $columnName)
{
return $this->_key($tableName, $columnName);
}
/**
* Get the index key name for a given column on this table
*/
function _key($tableName, $columnName)
{
return "{$tableName}_{$columnName}_idx";
}
/**
* MySQL doesn't take 'DROP CONSTRAINT', need to treat unique keys as
* if they were indexes here.
*
* @param array $phrase
* @param <type> $keyName MySQL
*/
function appendAlterDropUnique(array &$phrase, $keyName)
{
$phrase[] = 'DROP INDEX ' . $keyName;
}
/**
* Throw some table metadata onto the ALTER TABLE if we have a mismatch
* in expected type, collation.
*/
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function appendAlterExtras(array &$phrase, $tableName, array $def)
{
// Check for table properties: make sure we're using a sane
// engine type and charset/collation.
// @fixme make the default engine configurable?
$oldProps = $this->getTableProperties($tableName, array('ENGINE', 'TABLE_COLLATION'));
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$engine = $this->preferredEngine($def);
if (strtolower($oldProps['ENGINE']) != strtolower($engine)) {
$phrase[] = "ENGINE=$engine";
}
if (strtolower($oldProps['TABLE_COLLATION']) != 'utf8_bin') {
$phrase[] = 'DEFAULT CHARSET=utf8';
$phrase[] = 'COLLATE=utf8_bin';
}
}
/**
* Is this column a string type?
*/
private function _isString(array $cd)
{
$strings = array('char', 'varchar', 'text');
return in_array(strtolower($cd['type']), $strings);
}
/**
* 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)
{
$line = array();
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$line[] = parent::columnSql($cd);
// This'll have been added from our transform of 'serial' type
if (!empty($cd['auto_increment'])) {
$line[] = 'auto_increment';
}
if (!empty($cd['description'])) {
$line[] = 'comment';
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$line[] = $this->quoteValue($cd['description']);
}
return implode(' ', $line);
}
function mapType($column)
{
$map = array('serial' => 'int',
'integer' => 'int',
'numeric' => 'decimal');
$type = $column['type'];
if (isset($map[$type])) {
$type = $map[$type];
}
if (!empty($column['size'])) {
$size = $column['size'];
if ($type == 'int' &&
in_array($size, array('tiny', 'small', 'medium', 'big'))) {
$type = $size . $type;
} else if (in_array($type, array('blob', 'text')) &&
in_array($size, array('tiny', 'medium', 'long'))) {
$type = $size . $type;
}
}
return $type;
}
function typeAndSize($column)
{
if ($column['type'] == 'enum') {
$vals = array_map(array($this, 'quote'), $column['enum']);
return 'enum(' . implode(',', $vals) . ')';
} else if ($this->_isString($column)) {
return parent::typeAndSize($column) . ' CHARSET utf8';
} else {
return parent::typeAndSize($column);
}
}
/**
* Filter the given table definition array to match features available
* in this database.
*
* This lets us strip out unsupported things like comments, foreign keys,
* or type variants that we wouldn't get back from getTableDef().
*
* @param array $tableDef
*/
function filterDef(array $tableDef)
{
foreach ($tableDef['fields'] as $name => &$col) {
if ($col['type'] == 'serial') {
$col['type'] = 'int';
$col['auto_increment'] = true;
}
if ($col['type'] == 'datetime' && isset($col['default']) && $col['default'] == 'CURRENT_TIMESTAMP') {
$col['type'] = 'timestamp';
}
$col['type'] = $this->mapType($col);
unset($col['size']);
}
if (!common_config('db', 'mysql_foreign_keys')) {
unset($tableDef['foreign keys']);
}
return $tableDef;
}
}