dba_handlers

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

dba_handlers — List all the handlers available

Description

dba_handlers(bool $full_info = false ): array

dba_handlers() list all the handlers supported by this extension.

Parameters

full_info: Turns on/off full information display in the result.

Return Values

Returns an array of database handlers. If full_info is set to true , the array will be associative with the handlers names as keys, and their version information as value. Otherwise, the result will be an indexed array of handlers names.

Note:
When the internal cdb library is used you will see cdb and cdb_make.

Examples

Example #1 dba_handlers() Example

<?php

echo "Available DBA handlers:\n";
foreach (dba_handlers(true) as $handler_name => $handler_version) {
 // clean the versions
 $handler_version = str_replace('$', '', $handler_version);
 echo " - $handler_name: $handler_version\n";
}

?>

The above example will output something similar to:

Available DBA handlers:
 - cdb: 0.75, Revision: 1.3.2.3 
 - cdb_make: 0.75, Revision: 1.2.2.4 
 - db2: Sleepycat Software: Berkeley DB 2.7.7: (08/20/99)
 - inifile: 1.0, Revision: 1.6.2.3 
 - flatfile: 1.0, Revision: 1.5.2.4

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User Contributed Notes 1 note

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cbemerine at gmail dot com ¶

16 years ago

A quick way to see which DBA handlers, without version numbers, that have been built into your version of MySQL on your system, use var_dump with dba_handler() as follows: 
<?php
var_dump ( "dba_handlers()" ); 
?>

Many distros build in these DBA Handlers by default: 
array(5) { [0]=> string(3) "cdb" [1]=> string(8) "cdb_make" [2]=> string(3) "db4" [3]=> string(7) "inifile" [4]=> string(8) "flatfile" }
using print and pre tags for readability: 
array(5) {
 [0]=>
 string(3) "cdb"
 [1]=>
 string(8) "cdb_make"
 [2]=>
 string(3) "db4"
 [3]=>
 string(7) "inifile"
 [4]=>
 string(8) "flatfile"
}
Note there are issues with dba_insert and dba_replace without building for either GDBM or QDBM.
 Here are two sources for the list of DBA handlers: (http://www.php-editors.com/php_manual/ref.dba.html and http://dewa03.unep.org/manuals/php_manual/ref.dba.html; )
CDBM & CDB compiles have issues with updates, you can read databases and write new database files, but you will be prevented from using dba_replace() and you may have issues with dba_insert().
NDBM & DBM are depreciated.
DB2, DB3 & DB4 (Berkeley DB Sleepycat Software / Oracle) Have read online about issues with dba_replace() and db4 specifically. Make sure you test your installation for correct usage of all DBA functions.
SDBM, TDB, TinyCDB were not listed on most of the sources I have found online. Those DBA handlers and the names of the developers were listed on the QDBM source forge site. How they interact with dba_replace() I do not know. You should be aware of their existence. 
GDBM and QDBM are the only other two DBA handlers I am aware of. Both are reported to allow PHP's dba_replace() function to work correctly so either may be an acceptable option. The following three restrictions of traditional DBM are not issues for either GDBM or QDBM: 1) a process can handle only one database; 2) the size of a key and a value is bounded; 3) a database file is sparse.
DBA handler benchmark compares QDBM, GDBM, NDBM, SDBM, TDB, CDB, BDB, QDBM-BT-ASC, QDBM-BT-RND, BDB-BT-ASC, BDB-BT-RND can be found here: (http://qdbm.sourceforge.net/benchmark.pdf); 
QDBM seems to offer significant improvements in speed over the other DBA Handlers, test in your environment to verify the results.

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