==================================================================
     CLIENT/SERVER VERSUS LAN
     ==================================================================
     PRODUCT :  R:BASE /V               VERSION    :  3.1C
     CATEGORY:  MULTI-USER              SUBCATEGORY:  NETWORKING
     ==================================================================
 
     Client/Server! That phrase appears all over the press these days: who's
     got it, who does what and to whom, and so forth. But just what is client/
     server all about? This article will answer that question and explain why
     working in a client/server environment is a benefit to you and your
     organization's data management.
 
     The idea behind the client/server environment is fundamentally quite
     simple. A relational database engine and its data reside on a centralized
     computer (the server), and users on PC workstations (the clients) are
     able to retrieve the data via some kind of query mechanism and integrate
     the data into the PC client's applications.
 
     A client/server setup can help centralize data that had been pooled in
     many LANs much the same as LANs helped centralize data that had been
     pooled in stand alone personal computers.
 
     Differences Between LANs and Client/Server Setups
     =================================================
     Some important differences exist, however, between LANs and client/server
     setups:
 
       <> In a LAN, the database typically resides on the server and the data-
          base software resides on the server as well, but the engine actually
          runs on the PC workstation. All queries are processed on the work-
          station. Plus, all rows are returned across the network and always
          processed at the workstation. In a client/server setup, the database
          engine resides AND RUNS on the centralized server. All processing
          occurs on the server, not the client. Just the results of the query
          are returned to the workstation.
 
          To illustrate, let's say you have a 100,000-record customer table
          and you want to see just the four customers you have in Rhode Island.
 
          On a LAN, all 100,000 records would have to come across the network
          to your workstation for the PC database engine to sort out which
          ones are to be discarded and which ones are to be retained (this
          example implies a non-indexed column search). If you have several
          people doing similar searches, you can easily imagine how much
          network performance degrades, thus slowing down every user on the
          network.
 
          In a client/server setup, the server locates the four rows and then
          only the four records that match the conditions of your query are
          sent to your workstation. By having the server handle the query,
          network traffic is greatly reduced.
 
     Server Database Software
     ========================
     Note that most DOS-based PC data-bases, which had to run in the DOS-
     enforced memory limit of 640K, evolved as flat-file databases with some
     workarounds added to simulate true relationality. (R:BASE, of course, is
     an exception, having always provided true relationality.) Server data-
     bases, in contrast, are fully functional, relational databases powered by
     SQL engines. Here is a list of some proven server databases with good
     performance and data-protection records:
 
       <> DB2
       <> ORACLE
       <> INGRES
       <> SQL Server (Sybase)
 
     These database products include query optimizers, unbeatable security
     systems, rules functionality to maintain data integrity, on-line backup
     systems, commit and rollback function- ality, and many other powerful
     features that until recently were available only on mini- and mainframe
     data- bases (and from R:BASE).
 
     For further information about the lack of data integrity and security in
     most PC databases, see page 289 of the March 31, 1992, issue of PC
     Magazine.
 
     Server Database Operating Systems
     =================================
     Another advantage of server databases is that they run under one of the
     following operating systems:
 
       <> VAX VMS
       <> UNIX
       <> OS/2
       <> MVS
 
     All four operating systems offer much greater performance and speed than
     DOS; all were designed from the start to be robust, multi-user operating
     systems; and all have undergone substantial fine-tuning over time. DOS,
     on the other hand, is inherently a single-tasking operating system.
 
     Summary
     =======
     In a nutshell, these are the benefits of a client/server environment:
 
       <> Centralized data
       <> Minimized network traffic
       <> Fully Functional Relational Data-bases
       <> Multi-user Operating System
 
     The next issue of the R:BASE Exchange will include an article about
     Vanguard and how it addresses the issues brought up here. You'll learn
     about Vanguard's inner workings and about its ingenious, flexible, and
     elegant design, which will in turn underscore the advantages of working
     in a client/server environment.