Introduction to Data Management

Accessing Databases With NonStop SQL
15873 Tandem Computers Incorporated 3-5
Data Security NonStop SQL provides data security by allowing you to specify authorization
restrictions on objects in your database. These restrictions ensure that only authorized
users can see or change this data. For example, suppose you are a database
administrator creating a table that contains data on company personnel. You might
want to make the entire table available to the Personnel Department but prevent other
departments from seeing private data like salary information or unlisted home
telephone numbers.
NonStop SQL statements operate with the standard GUARDIAN 90 security system
to let you control access to entire tables, views, and portions of the data dictionary
called catalogs. Any user or application program must have the proper authority to
examine, add, modify, or delete data in these objects.
NonStop SQL also provides security at the level of individual fields through
protection views. A protection view is a subset of the rows or columns in a single
table that can be secured separately. Thus, in a table containing customer credit
information, one user can be allowed to see only the customer’s name and address
while another can examine or change the customer’s credit rating.
Easy-to-Learn
Query Language
NonStop SQL uses the industry-standard Structured Query Language (SQL) to
describe and manipulate data. NonStop SQL complies with the SQL standards
established by both the American National Standards Institute (ANSI) and the
International Standards Organization (ISO).
NonStop SQL, the Tandem implementation of the ANSI SQL standard, is easy to learn
and to use. If you are a programmer, you can easily use it to develop and test even
complex and powerful applications; NonStop SQL lets you define, manipulate, and
control data with just a few concise statements. If you are a business professional
with minimal computer experience, you can still use this language with ease to
examine business data or make simple changes to it.
Dynamic SQL NonStop SQL provides an advanced programming feature known as Dynamic SQL.
With this feature, you can write a program that defines general SQL statements that
are not fully specified until execution time. Dynamic SQL supports interactive
commands entered from the terminal.
Special Extensions NonStop SQL extensions to standard SQL make it even easier to use:
SQL Conversational Interface (SQLCI), used for entering brief queries and
generating formatted reports, for testing SQL statements, and for running the
database utility programs
Database utility commands that simplify database administration and monitor
application performance