DBA_OPEN(3)								 1							       DBA_OPEN(3)

dba_open - Open database

SYNOPSIS

       resource dba_open (string  $path, string  $mode, [string  $handler], [mixed  $...])

DESCRIPTION

       dba_open(3) establishes a database instance for $path with $mode using $handler.

PARAMETERS

	      o $path
		- Commonly a regular path in your filesystem.

	      o $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. The database is  created  in  BTree  mode,  other
		modes (like Hash or Queue) are not supported.  Additionally you can set the database lock method with the next char. Use l to lock
		the database with a .lck file or d to lock the databasefile itself. It is important that all of your applications do this  consis-
		tently.   If you want to test the access and do not want to wait for the lock you can add t as third character. When you are abso-
		lutely sure that you do not require database locking you can do so by using - instead of l or d. When none of d, l or -  is  used,
		dba will lock on the database file as it would with d.

	      Note

		      There  can  only	be  one  writer for one database file. When you use dba on a web server and more than one request requires
		     write operations they can only be done one after another. Also read during write is not allowed. The dba extension uses locks
		     to prevent this. See the following table:

		     DBA locking

		     +-------------+---------------+---+---+---+---+---+---+---+
		     |already open |		   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "rl"  |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "rlt" |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "wl"  |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "wlt" |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "rd"  |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "rdt" |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "wd"  |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   | $mode = "wdt" |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     +-------------+---------------+---+---+---+---+---+---+---+
		     |	not open   |		   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |$mode = "rl" |		   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 wait	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 false	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |$mode = "wl" |		   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 wait	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 false	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 wait	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 false	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |$mode = "rd" |		   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	  ok	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 wait	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 false	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |$mode = "wd" |		   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	illegal    |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 wait	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 false	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 wait	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     |		   |	 false	   |   |   |   |   |   |   |   |
		     |		   |		   |   |   |   |   |   |   |   |
		     +-------------+---------------+---+---+---+---+---+---+---+
			    ook: the second call will be successfull.

			    owait: the second call waits until dba_close(3) is called for the first.

			    ofalse: the second call returns false.

			    oillegal: you must not mix
			      "l" and "d" modifiers for $mode parameter.

	      o $handler
		-  The	name of the handler which shall be used for accessing $path. It is passed all optional parameters given to dba_open(3) and
		can act on behalf of them.

RETURN VALUES

	Returns a positive handle on success or FALSE on failure.

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 4.3.0	|						    |
       |	|						    |
       |	|  It's possible to open database files  over  net- |
       |	| work	connection.  However in cases a socket con- |
       |	| nection will be used (as with http  or  ftp)	the |
       |	| connection will be locked instead of the resource |
       |	| itself. This is important to know since  in  such |
       |	| cases  locking  is simply ignored on the resource |
       |	| and other solutions have to be found. 	    |
       |	|						    |
       +--------+---------------------------------------------------+
SEE ALSO

       dba_popen(3), dba_close(3).

PHP Documentation Group 													       DBA_OPEN(3)