Custom Access to the Database

This chapter describes three approaches you can use to provide a custom front-end capability for accessing the Cisco WAN Manager (CWM) Release 9.2 database. The first approach uses Informix-SQL as the front end, the second uses WingZ as the front end, and the third uses the Informix ESQL/C to compile a custom front-end program.

Informix-SQL

Informix-SQL from Informix Software Inc. is a standard software package that operates with an Informix database engine. The two programs together provide a complete database management system. Using the Structured Query Language (SQL) and Informix commands, you can create, delete, read and update relational databases.

When used as an alternative front end to CWM, the database engine program is Informix OnLine and the database is created and updated by CWM. The Informix-SQL front end is used in read only mode.

Figure 2-1: Informix-SQL as a Front End

Informix-SQL should be installed and started to operate concurrently with CWM. Installation consists of deciding the directory to store the program, creating informix user and group accounts, copying the software from the distribution media to the desired directory, and invoking the installsql script. Full details of the installation process are provided by Informix with the software.

Once the environment variables INFORMIXDIR, PATH, INFORMIXTERM, and TERM are set (Informix and UNIX documentation provide the details), you can start the main program (ISQL).

ISQL is a menu-driven program providing you access to virtually all the Informix-SQL facilities. A Query-Language option permits you to create, delete, and modify databases using SQL.

CWM comes with a dbaccess application which allows you to browse the database on line and perform SQL queries. This application is useful for examining objects in the database and for invoking SQL scripts. The SQL scripts that can be imported into dbaccess, require the use of UNIX utilities (for example, echo and pipe) and SQL knowledge. The rsh scripts can be used to feed data to other applications.

WingZ

WingZ is an advanced spreadsheet program that operates under UNIX, and within the OSF/Motif environment, providing a friendly graphical interface. WingZ includes HyperScript---a WingZ control language---which allows the automation of tasks.

DataLink is a WingZ hyperscript application that allows you to interact with SQL databases. DataLink operates concurrently with WingZ. The OSF/Motif environment allows you to display, size, and move multiple windows on the screen.

Figure 2-2: WingZ /DataLink as a Front End

When CWM, WingZ, and DataLink are running, a DataLink menu is added to the standard WingZ menu. Through this menu, you can log on to the CWM database and display the database tables' rows and columns. Under this arrangement, the WingZ HyperScript application can be used to create sequences of tasks which can be executed automatically.

Data can be displayed selectively using Boolean-like criteria, and tables can be joined so data from multiple tables can be included in a single display.

For details on WingZ and DataLink installation and operation, refer to the Informix documentation supplied with the CWM software.

ESQL/C

Development of ESQL-C applications requires an ESQL-C compiler (a special purpose compiler from Informix Software Inc.). This compiler (not included with the CWM product) can precompile the macros used within the application code.

The ESQL-C compiler accepts as input, C programs containing embedded SQL statements. It compiles the program into a C program by converting the SQL statements into suitable declarations and function calls using an SQL library.

The resulting C program is then compiled with a system C compiler to produce the executable code. This front-end program is a truly a custom front end as the program is entirely under the control of the programmer.

Figure 2-3: Custom Front End using ESQL/C

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