dba_exists
Description
bool dba_exists ( string key, resource handle)dba_exists() checks whether the specified key exists in the database specified by handle.
Key is the key the check is performed for.
Handle is a database handle returned by dba_open().
dba_exists() returns TRUE or FALSE, if the key is found or not found, respectively.
See also: dba_fetch(), dba_delete(), dba_insert(), and dba_replace().