All VAX RdblVMS data definitions must be stored in the CDD in order to be used by VAX DAThTRIEVE, VAX TDMS and/or VAX ACMS. Otherwise, storage of VAX RdbNMS data definitions in the CDD is optional.
VAXTDMS
All VAX TDMS form and request definitions are stored in the CDD.
VAXACMS
All VAX ACMS task, menu, application, and task group definitions are stored in theCDD.
3-13
Languages
In addition, several of the VAX programming languages can access CDD record definitions at compile time. The VAX languages that can use the CDD are
• VAXCOBOL
• VAXBASIC
• VAXPU!
• VAXDIBOL
Using the CDDL, it is possible to specify special conditions required by a partic-ular language compiler without affecting other use of the same definition by other compilers.
• Summary
The VAX Common Data Dictionary, then, helps the system manager coordinate an effective data management system; it reduces programming and mainte-nancecosts; and it
ties
together VAX programming languages and VAXliIf<>hnatiQh
Architectute products.Chapter 4 • VAX DATATRIEVE
VAX DATATRIEVE is an easy-to-use tool for managing and manipulating data either interactively at a terminal or from an applications program. If you know a handful of simple, English-like commands and statements, you can interactively retrieve, store, modify, and sort data, and report on it in meaningful ways.
With VAX DATA1RIEVE, you can:
• Create data definitions that can be used to store and retrieve data uniformly, either interactively or from application programs
• Store or modify data in RMS files, VAX DBMS databases, or VAX Rdb databases
• Retrieve data from RMS files, VAX DBMS databases, or VAX RdblVMS databases and display the data on a terminal, write it to a data file, or print it on paper
• Produce formatted reports using specified selections of data
• Create pie charts, bar graphs, line graphs, and scatter plots based on specified selections of data
• Use forms to format the terminal screen for data display or data collection
• Use a text editor to correct syntax errors and typing mistakes
• Access RMS, DBMS and Rdb data files located on remote systems
• Call VAX DATATRIEVE functions (including data access) from a program written in a high-level VAX programming language such as COBOL, FORTRAN, or PLil
• Who Uses VAX DATATRIEVE
VAX DATA1RIEVE is intended for a broad spectrum of users, including:
• Managers who need ready access to different views of data for decision-making and/or monitoring purposes
• Organizations that need a data storage system that can be run by clerical personnel
4-2 • VAXDATATRIEVE
• Organizations that need to access data on a distributed network without being concerned with where the data is actually located
• Applications programmers who want to save coding/debugging time and source space by having VAX. DATATRIEVE handle such functions as: finding and opening data files, performing input and output 'operations, formatting data, converting data types,himdliiig error and end-of"file conditions With its set of simple, English-like statements, VAX. DATATRIEVE is designed to be used by people with only modest computer experience as well as by com-puter professionals. It includes a special tutorial facility called Guide Mode to hdp any user get started quickly.
• Benefits of VAX DATATRIEVE
VAX. DAD\TRlEVE provides the folloWing benefits:
• Extensive use of the VAX CDD, making it unnecessary for you, in . DATATRIEVE, to specify locations,and definitions as you would with a
tradi-tional programming language
• An
English-like query language that allows easy access to data stored in RMS files, VAX. DBMS databases; and VAX. Rdb databases• An Applications Devdopment Tool (ADT) thai: provides a simple, interactive means of defining record formats, RMS files, and VAX. DATATRIEVE procedures
• A Report Writer that' allows you to' create formatted reports on any desired selection of data
• A text editor (callable EDT) for easily changing record definitions or cor-recting syntax errors
• Support for the forms management facilities of VAX. FMS and VAX. TDMS, which allow you to-format the screen for data display or collection purposes
• Graphics support that allo~ you to create a variety of color or black-and-white charts and plots based on specified sdections of data
• A tutorial called Guide Mode that introduces you to VAX. DAIATRIEVE
• A distributed access facility that allows you to access data stored
on
remOte systems• Security and protection facilities that allow you to limit access to data defini-tions and to protect those definidefini-tions from corruption
4-3
• A Closer Look at VAX DATATRIEVE
Using VAX DATATRIEVE involves:
• Using Guide Mode to learn VAX DATATRIEVE
• Creating special data definitions called domains, as well as record definitions, and storing them in the Common Data Dictionary (eDD)
• Retrieving and displaying data
• Storing and modifying data
• Using the VAX DATATRIEVE editor to correct errors in command lines
• Using relational facilities such as CROSS, which dynamically joins separate files
• Writing and using procedures
• Using the Report Writer facility to create formatted reports
• Using the graphics facility to create charts and graphs
• Calling VAX DATATRIEVE facilities from application programs
• Using forms to format the terminal for data entry and data display Using Guide Mode to Learn VAX DATATRIEVE
VAX DATATRIEVE provides a tutorial facility called Guide Mode. It is particu-larly useful to the inexperienced user who wants assistance during a VAX DATATRIEVE session.
You use the SET GUIDE command to invoke Guide Mode. Guide Mode then helps you through a VAX DATATRIEVE session with a series of prompts. At any time in this mode of operation, you can request a list of commands, statements, names, or value expressions that you can enter.
Creating and Storing Domains
When you use VAX DATATRIEVE to manage or manipulatedata, the data you work with is made available to you through special data structures called domains. A domain relates a data file to a CDD record definition that describes the data fields in that file.
The domain allows you to access data without having to describe the data or specify where it is located. In other words, when you access data with VAX DATATRIEVE, you can often specify the data you want with a single name. In contrast, if you were to use a VAX COBOL program to access the same data, you would need to describe the data to be accessed and specify where it was physi-cally located (device and file name).
4-4 • VAX DATATRlEVE
Domains are stored as domain definitions. In its simplestform, a domain defini-tion consists of the name of the domain, the name of a record definidefini-tion, and the name of a data file. In effect, then, a domain associates a record definition with a data file that consists of records stored in the same format.
The following is an example of a domain definition: