RDMs flexible architecture gives you a variety of configurations. Use RDM in a client/server or peer-to-peer (embedded) application on almost any hardware and software combination. RDM can take full advantage of memory as the main storage medium and persistent data can be stored on-disk.
A Deeper Dive
RDM’s runtime environment is composed as two powerful but well-defined modules:
- The Runtime Library – This re-entrant linkable library becomes part of your executable program. It maintains a cache of database objects as it responds to function calls from your program.
- The Transactional File Server – This tight, multi-user server interacts with one or more Runtime Libraries concurrently. It manages access to database files. The TFS responds to runtime requests to read objects, to lock objects, or to apply transactional changes.
As a re-entrant library, RDM fully supports multi-threaded applications. Each thread may open a database and operate on it concurrently with the others.
As a linkable library, RDM operates on data kept in a heap-based cache. Its robust APIs give you full visibility and control over the data. SQL is available through a C-based API, but also accessible through 3rd party tools. Other APIs allow fine-tuning of database operations using a cursor view or an object-oriented view.
Transactional File Server
At its core, the TFS is a library of functions. These functions are called by the runtime library. If the TFS is running in a separate process, its functions are called as RPCs (Remote Procedure Calls) using TCP/IP between computers and shared memory within the same computer.
However, the TFS functions may be linked directly into your application also. This has significant performance benefits and simplicity in operation. It’s faster because the Remote Procedure Calls become Local Procedure Calls (in-process). It’s simpler because everything is running within your program and there is no separate process to start first.
Yes, the Runtime Library and TFS are powerful and well-defined, but they can be configured in several ways. The figures below show just a few.