<?php
/**
* Driver class file.
*
* @link http://www.yiiframework.com/
* @copyright Copyright © 2008-2012 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\db\dao;
use yii\db\Exception;
/**
* Driver is the base class for all database driver classes.
*
* Driver implements the DBMS-specific methods to support retrieving metadata of a database.
*
* @property QueryBuilder $queryBuilder the query builder for this connection.
* @property array $tableNames the names of all tables in this database.
* @property array $tableSchemas the metadata for all tables in this database.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
abstract class Driver extends \yii\base\Object
{
/**
* The followings are the supported abstract column data types.
*/
const TYPE_PK = 'pk';
const TYPE_STRING = 'string';
const TYPE_TEXT = 'text';
const TYPE_SMALLINT = 'smallint';
const TYPE_INTEGER = 'integer';
const TYPE_BIGINT = 'bigint';
const TYPE_FLOAT = 'float';
const TYPE_DECIMAL = 'decimal';
const TYPE_DATETIME = 'datetime';
const TYPE_TIMESTAMP = 'timestamp';
const TYPE_TIME = 'time';
const TYPE_DATE = 'date';
const TYPE_BINARY = 'binary';
const TYPE_BOOLEAN = 'boolean';
const TYPE_MONEY = 'money';
/**
* @var Connection the database connection
*/
public $connection;
/**
* @var array list of ALL table names in the database
*/
private $_tableNames = array();
/**
* @var array list of loaded table metadata (table name => TableSchema)
*/
private $_tables = array();
/**
* @var QueryBuilder the query builder for this database
*/
private $_builder;
/**
* Loads the metadata for the specified table.
* @param string $name table name
* @return TableSchema DBMS-dependent table metadata, null if the table does not exist.
*/
abstract protected function loadTableSchema($name);
/**
* Constructor.
* @param Connection $connection database connection.
*/
public function __construct($connection)
{
$this->connection = $connection;
}
/**
* Obtains the metadata for the named table.
* @param string $name table name. The table name may contain schema name if any. Do not quote the table name.
* @param boolean $refresh whether to reload the table schema even if it is found in the cache.
* @return TableSchema table metadata. Null if the named table does not exist.
*/
public function getTableSchema($name, $refresh = false)
{
if (isset($this->_tables[$name]) && !$refresh) {
return $this->_tables[$name];
}
$db = $this->connection;
$realName = $db->expandTablePrefix($name);
// temporarily disable query caching
if ($db->queryCachingDuration >= 0) {
$qcDuration = $db->queryCachingDuration;
$db->queryCachingDuration = -1;
}
if (!in_array($name, $db->schemaCachingExclude, true) && $db->schemaCachingDuration >= 0 && ($cache = \Yii::$application->getComponent($db->schemaCacheID)) !== null) {
$key = $this->getCacheKey($name);
if ($refresh || ($table = $cache->get($key)) === false) {
$table = $this->loadTableSchema($realName);
if ($table !== null) {
$cache->set($key, $table, $db->schemaCachingDuration);
}
}
$this->_tables[$name] = $table;
} else {
$this->_tables[$name] = $table = $this->loadTableSchema($realName);
}
if (isset($qcDuration)) { // re-enable query caching
$db->queryCachingDuration = $qcDuration;
}
return $table;
}
/**
* Returns the cache key for the specified table name.
* @param string $name the table name
* @return string the cache key
*/
public function getCacheKey($name)
{
return __CLASS__ . "/{$this->connection->dsn}/{$this->connection->username}/{$name}";
}
/**
* Returns the metadata for all tables in the database.
* @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
* @return array the metadata for all tables in the database.
* Each array element is an instance of [[TableSchema]] (or its child class).
*/
public function getTableSchemas($schema = '')
{
$tables = array();
foreach ($this->getTableNames($schema) as $name) {
if (($table = $this->getTableSchema($name)) !== null) {
$tables[] = $table;
}
}
return $tables;
}
/**
* Returns all table names in the database.
* @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
* If not empty, the returned table names will be prefixed with the schema name.
* @param boolean $refresh whether to fetch the latest available table names. If this is false,
* table names fetched previously (if available) will be returned.
* @return array all table names in the database.
*/
public function getTableNames($schema = '', $refresh = false)
{
if (!isset($this->_tableNames[$schema]) || $refresh) {
$this->_tableNames[$schema] = $this->findTableNames($schema);
}
return $this->_tableNames[$schema];
}
/**
* @return QueryBuilder the query builder for this connection.
*/
public function getQueryBuilder()
{
if ($this->_builder === null) {
$this->_builder = $this->createQueryBuilder();
}
return $this->_builder;
}
/**
* Refreshes the schema.
* This method cleans up the cached table schema and names
* so that they can be recreated to reflect the database schema change.
* @param string $tableName the name of the table that needs to be refreshed.
* If null, all currently loaded tables will be refreshed.
*/
public function refresh($tableName = null)
{
$db = $this->connection;
if ($db->schemaCachingDuration >= 0 && ($cache = \Yii::$application->getComponent($db->schemaCacheID)) !== null) {
if ($tableName === null) {
foreach ($this->_tables as $name => $table) {
$cache->delete($this->getCacheKey($name));
}
$this->_tables = array();
} else {
$cache->delete($this->getCacheKey($tableName));
unset($this->_tables[$tableName]);
}
}
}
/**
* Quotes a table name for use in a query.
* If the table name contains schema prefix, the prefix will also be properly quoted.
* @param string $name table name
* @return string the properly quoted table name
* @see quoteSimpleTableName
*/
public function quoteTableName($name)
{
if (strpos($name, '.') === false) {
return $this->quoteSimpleTableName($name);
}
$parts = explode('.', $name);
foreach ($parts as $i => $part) {
$parts[$i] = $this->quoteSimpleTableName($part);
}
return implode('.', $parts);
}
/**
* Quotes a simple table name for use in a query.
* A simple table name does not schema prefix.
* @param string $name table name
* @return string the properly quoted table name
*/
public function quoteSimpleTableName($name)
{
return strpos($name, "'") !== false ? $name : "'" . $name . "'";
}
/**
* Quotes a column name for use in a query.
* If the column name contains prefix, the prefix will also be properly quoted.
* @param string $name column name
* @return string the properly quoted column name
* @see quoteSimpleColumnName
*/
public function quoteColumnName($name)
{
if (($pos = strrpos($name, '.')) !== false) {
$prefix = $this->quoteTableName(substr($name, 0, $pos)) . '.';
$name = substr($name, $pos + 1);
} else {
$prefix = '';
}
return $prefix . $this->quoteSimpleColumnName($name);
}
/**
* Quotes a simple column name for use in a query.
* A simple column name does not contain prefix.
* @param string $name column name
* @return string the properly quoted column name
*/
public function quoteSimpleColumnName($name)
{
return strpos($name, '"') !== false || $name === '*' ? $name : '"' . $name . '"';
}
/**
* Creates a query builder for the database.
* This method may be overridden by child classes to create a DBMS-specific query builder.
* @return QueryBuilder query builder instance
*/
public function createQueryBuilder()
{
return new QueryBuilder($this->connection);
}
/**
* Returns all table names in the database.
* This method should be overridden by child classes in order to support this feature
* because the default implementation simply throws an exception.
* @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
* If not empty, the returned table names will be prefixed with the schema name.
* @return array all table names in the database.
*/
protected function findTableNames($schema = '')
{
throw new Exception(get_class($this) . 'does not support fetching all table names.');
}
}