HP System Dictionary/XL SDMAIN Reference Manual (32256-90001)

1- 9
1 Introducing the System Dictionary
SDMAIN Program
Product Overview
HP System Dictionary SDMAIN is a program that allows you to access the System Dictionary product.
You can:
• Enter and maintain data in HP System Dictionary
• Report on and make queries about the data residing in HP System Dictionary
This access is achieved by means of a command language. This manual describes the HP System
Dictionary Command Language--both its syntax and usage. Examples are given showing how the
commands are used within common types of applications.
If you are a new user of HP System Dictionary, you will need an understanding of what a data dictionary is
along with its purpose and function.
What is a Data Dictionary?
Just as an ordinary dictionary is a collection of definitions of words, a data dictionary is a collection of
definitions and descriptions of data that resides on a computer system. In a dictionary, the smallest unit of
information is a word, whereas, in a data dictionary, the smallest unit of information is a data element.
The data dictionary does not contain the data itself, but contains metadata --data about data. This
metadata can be descriptions and definitions of various kinds. It can describe such things as:
Data: Names and definitions of data elements
Data Relationships: How data is related to other data
Data Responsibility: Who is responsible for what data
Organizational Structure: The information flow, who uses the data
Location Information: Where files, programs, and reports reside
Security Information: Who has access to what data
A typical example of a piece of metadata is a data element called "SSN" which represents a piece of data--a
social security number. The social security number itself does not reside in the dictionary, but a
description of that piece of data does. For instance, the data dictionary might tell you the name of the data
element, the storage length, the display or output length, the type of data (numeric or character), its sign if
the element is numeric, what database or program that data resides in, and possibly what departments in
the organization use and maintain that data.
The data dictionary, therefore, serves many purposes. You can use it as a quick directory to the
information that resides on a computer system--where to go to get pieces of data. You can also, however,
use it as one of the primary means for ensuring consistency of data definitions and preventing data
redundancy. This means that programmers and developers may be required to check the data dictionary
for data elements that already exist on their system before they design a new program. Therefore, if a data
element already exists on the system describing a social security number (for example, "SSN" ), the
dictionary reports this information and does not allow the programmer to add a new element with the
same name. This helps an organization to save time in program development by using data definitions