get.so

berkeley db 4.6.21的源码。berkeley db是一个简单的数据库管理系统

m4_comment([$Id: get.so,v 10.18 2003/10/18 19:15:52 bostic Exp $])

m4_ref_title(Access Methods,
    Retrieving records, @retrieving records, am/opensub, am/put)

m4_p([dnl
The m4_refT(dbh_get) retrieves records from the database.  In general,
m4_ref(dbh_get) takes a key and returns the associated data from the
database.])

m4_p([dnl
There are a few flags that you can set to customize retrieval:])

m4_tagbegin
m4_tag([m4_ref(DB_GET_BOTH)], [dnl
Search for a matching key and data item, that is, only return success
if both the key and the data items match those stored in the database.])

m4_tag([m4_ref(DB_RMW)], [dnl
Read-modify-write: acquire write locks instead of read locks during
retrieval. This can enhance performance in threaded applications by
reducing the chance of deadlock.])

m4_tag([m4_ref(DB_SET_RECNO)], [dnl
If the underlying database is a Btree, and was configured so that it
is possible to search it by logical record number, retrieve a specific
record.])

m4_tagend

m4_p([dnl
If the database has been configured to support duplicate records,
m4_ref(dbh_get) will always return the first data item in the duplicate
set.])

m4_page_footer