参数

path

Commonly a regular path in your filesystem.

mode

It is r for read access, w for read/write access to an already existing database, c for read/write access and database creation if it doesn't currently exist, and n for create, truncate and read/write access.

handler

The name of the handler which shall be used for accessing path. It is passed all optional parameters given to dba_popen() and can act on behalf of them.

args

Optional string parameters which are passed to the driver.

The cdb, cdb_make, flatfile, inifile, qdbm and tcadb drivers do not support additional parameters.

The db1, db2, db3, db4, dbm, gdbm, and ndbm drivers supports a single additional parameter $filemode, which has the same meaning as the $mode parameter of chmod(), and defaults to 0644.

The lmdb driver accepts two additional parameters. The first allows to specify the $filemode (see description above), and the second to specify the $mapsize, where the value should be a multiple of the page size of the OS, or zero, to use the default mapsize. The $mapsize parameter is supported as of PHP 7.3.14 and 7.4.2, respectively.