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Diffstat (limited to 'framework/Db/schema/TDbSchema.php')
| -rwxr-xr-x | framework/Db/schema/TDbSchema.php | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/framework/Db/schema/TDbSchema.php b/framework/Db/schema/TDbSchema.php new file mode 100755 index 00000000..f7e889ec --- /dev/null +++ b/framework/Db/schema/TDbSchema.php @@ -0,0 +1,193 @@ +<?php +/** + * TDbSchema class file. + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @link http://www.yiiframework.com/ + * @copyright Copyright © 2008-2009 Yii Software LLC + * @license http://www.yiiframework.com/license/ + */ + +prado::using('System.db.schema.TDbCommandBuilder'); + +/** + * TDbSchema is the base class for retrieving metadata information. + * + * @author Qiang Xue <qiang.xue@gmail.com> + * @version $Id$ + * @package system.db.schema + * @since 1.0 + */ +abstract class TDbSchema extends TComponent +{ + private $_tableNames=array(); + private $_tables=array(); + private $_connection; + private $_builder; + private $_cacheExclude=array(); + + /** + * Creates a table instance representing the metadata for the named table. + * @return TDbTableSchema driver dependent table metadata, null if the table does not exist. + */ + abstract protected function createTable($name); + + /** + * Constructor. + * @param TDbConnection database connection. + */ + public function __construct($conn) + { + $conn->setActive(true); + $this->_connection=$conn; + foreach($conn->schemaCachingExclude as $name) + $this->_cacheExclude[$name]=true; + } + + /** + * @return TDbConnection database connection. The connection is active. + */ + public function getDbConnection() + { + return $this->_connection; + } + + /** + * Obtains the metadata for the named table. + * @param string table name + * @return TDbTableSchema table metadata. Null if the named table does not exist. + */ + public function getTable($name) + { + if(isset($this->_tables[$name])) + return $this->_tables[$name]; + else if(!isset($this->_cacheExclude[$name]) && ($duration=$this->_connection->schemaCachingDuration)>0 && ($cache=prado::getApplication()->getCache())!==null) + { + $key='prado:dbschema'.$this->_connection->connectionString.':'.$this->_connection->username.':'.$name; + if(($table=$cache->get($key))===false) + { + $table=$this->createTable($name); + $cache->set($key,$table,$duration); + } + return $this->_tables[$name]=$table; + } + else + return $this->_tables[$name]=$this->createTable($name); + } + + /** + * Returns the metadata for all tables in the database. + * @param string 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 {@link TDbTableSchema} (or its child class). + * The array keys are table names. + * @since 1.0.2 + */ + public function getTables($schema='') + { + $tables=array(); + foreach($this->getTableNames($schema) as $name) + $tables[$name]=$this->getTable($name); + return $tables; + } + + /** + * Returns all table names in the database. + * @param string the schema of the tables. Defaults to empty string, meaning the current or default schema. + * If not empty, the returned table names will be prefixed with the schema name. + * @return array all table names in the database. + * @since 1.0.2 + */ + public function getTableNames($schema='') + { + if(!isset($this->_tableNames[$schema])) + $this->_tableNames[$schema]=$this->findTableNames($schema); + return $this->_tableNames[$schema]; + } + + /** + * @return TDbCommandBuilder the SQL command builder for this connection. + */ + public function getCommandBuilder() + { + if($this->_builder!==null) + return $this->_builder; + else + return $this->_builder=$this->createCommandBuilder(); + } + + /** + * Refreshes the schema. + * This method resets the loaded table metadata and command builder + * so that they can be recreated to reflect the change of schema. + */ + public function refresh() + { + $this->_tables=array(); + $this->_builder=null; + } + + /** + * Quotes a table name for use in a query. + * @param string table name + * @return string the properly quoted table name + */ + public function quoteTableName($name) + { + return "'".$name."'"; + } + + /** + * Quotes a column name for use in a query. + * @param string column name + * @return string the properly quoted column name + */ + public function quoteColumnName($name) + { + return '"'.$name.'"'; + } + + /** + * Compares two table names. + * The table names can be either quoted or unquoted. This method + * will consider both cases. + * @param string table name 1 + * @param string table name 2 + * @return boolean whether the two table names refer to the same table. + */ + public function compareTableNames($name1,$name2) + { + $name1=str_replace(array('"','`',"'"),'',$name1); + $name2=str_replace(array('"','`',"'"),'',$name2); + if(($pos=strrpos($name1,'.'))!==false) + $name1=substr($name1,$pos+1); + if(($pos=strrpos($name2,'.'))!==false) + $name2=substr($name2,$pos+1); + return $name1===$name2; + } + + /** + * Creates a command builder for the database. + * This method may be overridden by child classes to create a DBMS-specific command builder. + * @return TDbCommandBuilder command builder instance + */ + protected function createCommandBuilder() + { + return new TDbCommandBuilder($this); + } + + /** + * Returns all table names in the database. + * This method should be overridden by child classes in order to support this feature + * because the default implemenation simply throws an exception. + * @param string the schema of the tables. Defaults to empty string, meaning the current or default schema. + * If not empty, the returned table names will be prefixed with the schema name. + * @return array all table names in the database. + * @since 1.0.2 + */ + protected function findTableNames($schema='') + { + throw new TDbException('{0} does not support fetching all table names.', + get_class($this)); + } +} |