Class CDbCache

CDbCache implements a cache application component by storing cached data in a database.

CDbCache stores cache data in a DB table named CDbCache::$cacheTableName. If the table does not exist, it will be automatically created. By setting CDbCache::$autoCreateCacheTable to false, you can also manually create the DB table.

CDbCache relies on PDO to access database. By default, it will use a SQLite3 database under the application runtime directory. You can also specify CDbCache::$connectionID so that it makes use of a DB application component to access database.

See CCache manual for common cache operations that are supported by CDbCache.

CComponent

CApplicationComponent implements IApplicationComponent

CCache implements ICache, ArrayAccess

CDbCache

Package: system\caching
Copyright: 2008-2013 Yii Software LLC
License: http://www.yiiframework.com/license/
Author: Qiang Xue <qiang.xue@gmail.com>
Since: 1.0
Located at x2engine/framework/caching/CDbCache.php

Methods summary
`public`	# `init( )` Initializes this application component. Initializes this application component. This method is required by the `IApplicationComponent` interface. It ensures the existence of the cache DB table. It also removes expired data items from the cache. Overrides `CCache::init()`
`public integer`	# `getGCProbability( )` Returns `integer` the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
`public`	# `setGCProbability( integer $value )` Parameters `$value` `integer` $value the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance. This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all.
`protected`	# `createCacheTable( CDbConnection $db, string $tableName )` Creates the cache DB table. Creates the cache DB table. Parameters `$db` `CDbConnection` $db the database connection `$tableName` `string` $tableName the name of the table to be created
`public CDbConnection`	# `getDbConnection( )` Returns `CDbConnection` the DB connection instance Throws `CException` if `CDbCache::$connectionID` does not point to a valid application component.
`public`	# `setDbConnection( CDbConnection $value )` Sets the DB connection used by the cache component. Sets the DB connection used by the cache component. Parameters `$value` `CDbConnection` $value the DB connection instance Since 1.1.5
`protected string\|boolean`	# `getValue( string $key )` Retrieves a value from cache with a specified key. This is the implementation of the method declared in the parent class. Retrieves a value from cache with a specified key. This is the implementation of the method declared in the parent class. Parameters `$key` `string` $key a unique key identifying the cached value Returns `string\|boolean` the value stored in cache, false if the value is not in the cache or expired. Throws `CException` if this method is not overridden by child classes Overrides `CCache::getValue()`
`protected array`	# `getValues( array $keys )` Retrieves multiple values from cache with the specified keys. Retrieves multiple values from cache with the specified keys. Parameters `$keys` `array` $keys a list of keys identifying the cached values Returns `array` a list of cached values indexed by the keys Overrides `CCache::getValues()`
`protected boolean`	# `setValue( string $key, string $value, integer $expire )` Stores a value identified by a key in cache. This is the implementation of the method declared in the parent class. Stores a value identified by a key in cache. This is the implementation of the method declared in the parent class. Parameters `$key` `string` $key the key identifying the value to be cached `$value` `string` $value the value to be cached `$expire` `integer` $expire the number of seconds in which the cached value will expire. 0 means never expire. Returns `boolean` true if the value is successfully stored into cache, false otherwise Throws `CException` if this method is not overridden by child classes Overrides `CCache::setValue()`
`protected boolean`	# `addValue( string $key, string $value, integer $expire )` Stores a value identified by a key into cache if the cache does not contain this key. This is the implementation of the method declared in the parent class. Stores a value identified by a key into cache if the cache does not contain this key. This is the implementation of the method declared in the parent class. Parameters `$key` `string` $key the key identifying the value to be cached `$value` `string` $value the value to be cached `$expire` `integer` $expire the number of seconds in which the cached value will expire. 0 means never expire. Returns `boolean` true if the value is successfully stored into cache, false otherwise Throws `CException` if this method is not overridden by child classes Overrides `CCache::addValue()`
`protected boolean`	# `deleteValue( string $key )` Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class. Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class. Parameters `$key` `string` $key the key of the value to be deleted Returns `boolean` if no error happens during deletion Throws `CException` if this method is not overridden by child classes Overrides `CCache::deleteValue()`
`protected`	# `gc( )` Removes the expired data values. Removes the expired data values.
`protected boolean`	# `flushValues( )` Deletes all values from cache. This is the implementation of the method declared in the parent class. Deletes all values from cache. This is the implementation of the method declared in the parent class. Returns `boolean` whether the flush operation was successful. Throws `CException` if this method is not overridden by child classes Since 1.1.5 Overrides `CCache::flushValues()`

Methods inherited from CCache
`add(), delete(), flush(), generateUniqueKey(), get(), mget(), offsetExists(), offsetGet(), offsetSet(), offsetUnset(), set()`

Methods inherited from CApplicationComponent
`getIsInitialized()`

Methods inherited from CComponent
`__call(), __get(), __isset(), __set(), __unset(), asa(), attachBehavior(), attachBehaviors(), attachEventHandler(), canGetProperty(), canSetProperty(), detachBehavior(), detachBehaviors(), detachEventHandler(), disableBehavior(), disableBehaviors(), enableBehavior(), enableBehaviors(), evaluateExpression(), getEventHandlers(), hasEvent(), hasEventHandler(), hasProperty(), raiseEvent()`

Properties summary
`public string`	`$connectionID`		# the ID of the `CDbConnection` application component. If not set, a SQLite3 database will be automatically created and used. The SQLite database file is `<span class="php-keyword1">protected</span>/runtime/cache-YiiVersion.db`. the ID of the `CDbConnection` application component. If not set, a SQLite3 database will be automatically created and used. The SQLite database file is `<span class="php-keyword1">protected</span>/runtime/cache-YiiVersion.db`.
`public string`	`$cacheTableName`	`'YiiCache'`	# name of the DB table to store cache content. Defaults to 'YiiCache'. Note, if `CDbCache::$autoCreateCacheTable` is false and you want to create the DB table manually by yourself, you need to make sure the DB table is of the following structure: (id CHAR(128) PRIMARY KEY, expire INTEGER, value BLOB) Note, some DBMS might not support BLOB type. In this case, replace 'BLOB' with a suitable binary data type (e.g. LONGBLOB in MySQL, BYTEA in PostgreSQL.) name of the DB table to store cache content. Defaults to 'YiiCache'. Note, if `CDbCache::$autoCreateCacheTable` is false and you want to create the DB table manually by yourself, you need to make sure the DB table is of the following structure: (id CHAR(128) PRIMARY KEY, expire INTEGER, value BLOB) Note, some DBMS might not support BLOB type. In this case, replace 'BLOB' with a suitable binary data type (e.g. LONGBLOB in MySQL, BYTEA in PostgreSQL.) See `CDbCache::$autoCreateCacheTable`
`public boolean`	`$autoCreateCacheTable`	`true`	# whether the cache DB table should be created automatically if it does not exist. Defaults to true. If you already have the table created, it is recommended you set this property to be false to improve performance. whether the cache DB table should be created automatically if it does not exist. Defaults to true. If you already have the table created, it is recommended you set this property to be false to improve performance. See `CDbCache::$cacheTableName`

Properties inherited from CCache
`$hashKey, $keyPrefix, $serializer`

Properties inherited from CApplicationComponent
`$behaviors`

Magic properties summary
`public integer`	`$gCProbability`	# The probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance. The probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
`public CDbConnection`	`$dbConnection`	# The DB connection instance. The DB connection instance.

Magic properties inherited from CApplicationComponent
`$isInitialized`

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Class CDbCache

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