progmodel.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: progmodel.so,v 10.27 2001/03/01 15:57:54 bostic Exp $])

m4_ref_title(Architecture, Programming model,, arch/bigpic, arch/apis)

m4_p([dnl
m4_db is a database library, in which the library is linked into the
address space of the application using it.  The code using m4_db may be
a standalone application or it may be a server providing functionality
to many clients via inter-process or remote-process communication
(IPC/RPC).])

m4_p([dnl
In the standalone application model, one or more applications link the
m4_db library directly into their address spaces.  There may be many
threads of control in this model because m4_db supports locking for both
multiple processes and for multiple threads within a process.  This
model provides significantly faster access to the database
functionality, but implies trust among all threads of control sharing
the database environment because they will have the ability to read,
write and potentially corrupt each other's data.])

m4_p([dnl
In the client-server model, developers write a database server
application that accepts requests via some form of IPC/RPC, and issues
calls to the m4_db interfaces based on those requests.  In this model,
the database server is the only application linking the m4_db library
into its address space.  The client-server model trades performance for
protection because it does not require that the applications share a
protection domain with the server, but IPC/RPC is slower than a function
call.  Of course, this model also greatly simplifies the creation of
network client-server applications.])

m4_page_footer