dba_replace

(PHP 4, PHP 5)

dba_replace — エントリを置換または挿入する

説明

bool dba_replace ( string $key , string $value , resource $handle )

dba_replace() は、handle で指定したデータベースに key および value で記述されるエントリを置換または挿入します。

パラメータ

key: 置換するエントリのキー。
value: 置換される値。
handle: dba_open() あるいは dba_popen() によって返されたデータベースハンドル。

返り値

成功した場合に TRUE を、失敗した場合に FALSE を返します。

参考

dba_sync

dba_popen

Last updated: Fri, 10 Oct 2008

add a note User Contributed Notes
dba_replace

samuele at removethisnorsam dot org
04-Aug-2003 04:23


For a short explanation about disk space usage, see user contrib note at dba_optimize()

jelte dot werkhoven at itfy dot com
26-Sep-2002 07:24


Not only will dba_replace add extra entries when trying to replace an existing smaller one, it will always add a new entry if the size of the value differs from the existing entry. This is probably due to the nature of the datum struct in DBM-type databases (I work with gdbm), which consist of a void pointer and a integer containing the size of the memory pointed to. Padding the value should solve this.

swain at panix dot com
06-Nov-2001 11:03


Note that if you replace an existing entry with a larger one, it will actually create a new entry and the old one is simply lost. This is a memory leak in other words.





You might want to try padding your values to a certain size before putting them in the db file; for example, if you are storing web pages in the db, pad them out to the next 500 byte size with spaces, and strip the spaces when you read it out. This will go a long way in saving disk space. I've seen db files grow to several megabytes with only a couple hundred text files in them.

add a note

dba_sync

dba_popen

Last updated: Fri, 10 Oct 2008