Raima Database Manager++, Velocis Database Server
Manufacturer: Raima Corporation
RDM++ Price: $995 US (royalty free)
Velocis Price: $495 US (2 users)
Reviewer: Nick Xidis
Raima Corp. offers three products: the Raima Database Manager++ (RDM++, formerly db_Vista), a database management library for C, Raima Object Manager(ROM), a persistent class library for C++, and the Velocis database server, which supports both the RDM++ API and ANSI SQL. All three support transaction logging and recovery, compound keys and time stamping. The most unique feature of the Raima line-up is the combination of pointer and relational data navigation. I tested all three using Caldera's OpenLinux Standard 1.1 on a DEC P-90 with 40MB RAM. I'll cover the RDM++ and Velocis server in this review.
The installation is a snap. Just unpack the two floppies using tar and run the makeall shell script. RDM++ compiles with no significant errors. I had one minor gripe, the makeall shell script should ask for extra compile flags; I would have liked to add a -O3 flag.
To create databases, begin with a .ddl file that defines the schema for the database. Tables are defined in a format that is very similar to STRUCT in C. Also, defined in the .dll file are sets. Sets define pointers to other records in the database. So, one record in a table can point directly to another without joining. This combination of tables (relational data model) and sets (network-pointer data model) is where RDM++ really shines. Using sets to point to other records is like having a permanent predefined join between tables and can speed up your application compared to the process of iterating over tables to create joins at runtime. In practice, I found that having joins built into the database produced shorter and cleaner code than similar applications using ISAM libraries. Once the .ddl files are built, the ddlp utility compiles a database dictionary and header files that supply constants needed by your application from the database.
The C API for RDM++ is a snap to learn, as all the function calls start with d_ and are very intuitive. To open a database, just call d_open; to read a record, d_recread. Don't think that because the API is intuitive that it's not rich—there are over 200 functions. The learning curve is very short; I was able to produce simple C applications within a couple of hours. One of the biggest aids in learning the API was the dal utility that allows d_ calls to be entered at the command line, just as they are written in sources. Almost any of the d_ function calls can be run interactively, and the results can be seen right away.
Another great time saver is the db_QUERY utility. This allows reports to be produced from RDM++ databases using SQL. Both tables and sets can be accessed from db_QUERY—sets appear as SQL views. You can use it either interactively or with canned query files. The neatest capability is that you can embed db_QUERY inside C applications. I used it at the command line to work out my queries. Then with a few function calls the same report is generated inside of my C application. For simplicity, the functions all start with q_ and there are only twelve of them.
I found this whole system of creating a database easy to understand and a joy to use. The only piece missing is a GUI report writer. Raima makes a fairly good one for MS Windows, but not for X.
Single-user applications can just be executed; however, to use the RDM++ multi-user mode, a lock manager is required. The lock manager runs in a separate process and manages the file locks for all the users of your application. The multi-user mode worked well. Record-level locking is not enforced by the lock manager, so you'll have to limit the number of users to 20 or less.
This is the one area in which the RDM++ falls short. If serious multi-user applications are going to be built with RDM++, you need record locks. I realize that there is some overhead with this option, but it seems well worth the cost.
Velocis is a back office power house. It supports all of the standard stuff that you'd expect in the best commercial database servers: transaction processing, ACID transactions, record and table locks, stored procedures, triggers and hot backups. It also supports a wide set of APIs: RDM++ C API, ROM C++ API (for storing C++ objects), ANSI 89 and most of the 92 SQL API and SQL Access Group's Call Level Interface (SAG-CLI, which is the same as Microsoft's ODBC level 1 API). In addition, the server is easily extended with C or C++.
- March 2015 Issue of Linux Journal: System Administration
- High-Availability Storage with HA-LVM
- DNSMasq, the Pint-Sized Super Dæmon!
- Localhost DNS Cache
- Real-Time Rogue Wireless Access Point Detection with the Raspberry Pi
- Days Between Dates: the Counting
- The Usability of GNOME
- You're the Boss with UBOS
- Multitenant Sites
- Linux for Astronomers