Using the Network Database Simulator

Using the Network Database Simulator - NETSIM

NETSIM is a system that simulates a network database system, based on the DBTG model. It allows a program to access a simple network database, defined by a programmer-supplied data definition language (ddl) file. The program itself will contain embedded data manipulation language (dml) statements that are converted to "pure" source language statements by a pre-processor.

The original version of NETSIM was developed by Prof. Russell Bjork at Gordon College in 1988 for his Database Systems course, and has been used in several subsequent offerings of the course. It was designed to support DBTG dml statements embedded in a source program written in Pascal. In 1996-1997, NETSIM was re-written as a senior project by Karen Bailey and Simon Miner, so as to support accessing a simulated database by means of DBTG dml statements embedded in a source program written in C++. This version is being used for the first time in the Fall, 1998 offering of the Database Systems course.

The NETSIM network database system is documented by the following handouts:

To use NETSIM on Gordon's VAX-VMS system, include one of the following lines in your LOGIN.COM file (depending on which language you choose to use NETSIM with):

$ ASSIGN/JOB SYS$CSROOT:[CS352.352000.NETSIM-PASCAL] NETSIM
$ ASSIGN/JOB SYS$CSROOT:[CS352.352000.NETSIM-CPLUSPLUS] NETSIM

In either case, the relevant NETSIM system files are then accessible through the logical name NETSIM:.

The commands for compiling and linking a program using the Pascal version are as follows, assuming your source program is in file PROJ1.DML.

$ RUN NETSIM:NETPP
DML File: PROJ1
$ PASCAL PROJ1
$ LINK PROJ1, NETSIM:NETLIB/LIB

For the C++ version, the commands are:

$ RUN NETSIM:NETPP
DML File: DEMO
$ GCC/PLUS DEMO.CC
$ LINK DEMO, NETSIM:NETLIB/LIB, LIBGXX/OPT