- ^ Jelix components
- jTpl, template engine
- Zones
- jDao: relational object mapping
- Classic forms
- jForms: automatic forms
- jDb: accessing to SQL database
- jKVDb: accessing to key/value databases
- jUrl: automatic urls
- jAuth : authentication system
- jAcl2 : rights management
- jLocale: localization
- jEvents: communication between modules
Chapter: jKVDb: accessing to key/value databases
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Jelix has an abstract layer to access to key-value databases, less complex than SQL databases.
You have a jKVDb
from which you retrieve a connector to a key-value database. Like jDb, there are some "profiles", stored in the profiles.ini.php
file (See the corresponding chapter), where you define parameters to connect to these databases.
jKVDb works with some "drivers" to access to "key-value" data. Jelix provides drivers for simple files (file and file2), memcache, redis, and... sql. See below for more informations about this drivers.
Configuration ¶
As for jDb, profiles.ini.php
contains some section, one for each databases you want to access. Each section should contain at least, one parameter, driver
, indicating the name of the driver to use. Other parameters should be set, depending on the driver.
The connection type to indicate in profile names is jkvdb
.
Accessing to a database ¶
You must call jKVDb::getConnection()
, by giving eventually a profile (else the profile "default" is used). You retrieve an object inheriting from jKVDriver
.
With this object, you can access and modify the content of the key-value database. Here are some methods you can call:
get($key)
: to retrieve the value corresponding to the given key.set($key, $value)
: to store a new value or modify an existing valueinsert($key, $value)
: to store a new value. return false if the key already existsreplace($key,$value)
: to change the value of the corresponding key. If the key doesn't exist, it returns false.delete($key)
: delete the given key-valueflush()
: delete all keysappend($key, $value)
: append a string to an existing key valueprepend($key, $value)
: prepend a string to an existing key valueincrement($key)
: increment the value. You can indicate also the value of the incrementationdecrement($key)
: decrement the value. You can indicate also the value of the decrementation
Other specific operations ¶
Some drivers can implement additionnal methods, depending of the capabilites of the database. One of this interface is jIKVttl
, where values have a limited life time.
To store such values, you should call the method setWithTtl($key, $value, $ttl)
, where $ttl must be a value in seconds.
You can call also the garbage
method to delete all keys which are not anymore valid.
Drivers ¶
memcache ¶
It uses the Memcache API of PHP (don't confuse with the other API, memcached). It supports only the version 3.0.1 of memcache or lower.
In the profile, you have to indicate a host and a port, or several host/port. Example with a single server:
[jkvdb:mymemcacheserver]
driver=memcache
host=localhost
Or with several servers:
[jkvdb:mymemcacheserver]
driver=memcache
host=memcache_server1:11211;memcache_server2:11212
; or:
host[]=memcache_server1:11211
host[]=memcache_server2:11212
You can also set the parameter compress=1
, so values will be compressed during the storage.
This driver supports the jIKVttl
interface.
redis ¶
This driver allows to access to a Redis database. It uses the library php5redis. For the configuration, indicate a host
and a port
parameter.
[jkvdb:myredis]
driver=redis
host = localhost
port = 6379
This driver supports the jIKVttl
interface.
db ¶
It allows to use a SQL table as a storage for key-values. In the configuration, you must indicate:
table
: the name of the table to usedbprofile
: the name of the jDb profile to use to access to the sql database.
The table should contain three fields, with specific field names and types. here is a SQL script to create such tables:
CREATE TABLE mykvdbtable (
k_key VARCHAR( 50 ) NOT NULL ,
k_value longblob NOT NULL ,
k_expire DATETIME NOT NULL ,
PRIMARY KEY (k_key)
);
You can have several tables, to avoid conflict between all modules which use jKVDb.
This driver supports the jIKVttl
interface.
file ¶
It stores values in files. Each file content one value. Configuration:
storage_dir
: the directory where files are stored. Can contain shortcuts like "var:" or "temp:". default dir isvar/kvfiles/
.file_locking
: false to disable file locking. By default: true.automatic_cleaning_factor
: indicate the frequency to clean deprecated files.0
means never,1
means at each access, higher means a lower frequency.directory_level
: if you know that you'll have thousand values, you can increase the directory level. By default: 2.directory_umask
: umask of created directories. By default: 0700file_umask
: umask of created files. By default: 0600.
This driver supports the jIKVttl
interface.
file2 ¶
It is a driver similar to the "file" driver, but it is less sophisticated. It has no configuration parameters and store files into temp/filekv/
.
You must use it only for temporary values.