Introduction to NonStop SQL/MP

1 Introduction to NonStop SQL/MP
113425 Tandem Computers Incorporated 1–1
The NonStop SQL/MP relational database management system combines the standard
features of a relational database with additional features that provide data integrity,
high availability, high performance, and excellent scalability. NonStop SQL/MP is
specifically designed for large data processing environments that maintain a variety of
applications performing critical business tasks.
This section briefly describes a few types of business applications and shows how
NonStop SQL/MP satisfies the needs of those applications. It then discusses the
features that allow NonStop SQL/MP to provide high performance and availability.as
well as parallel processing, distributed processing, and support for open standards.
What Is a Relational
Database?
A relational database, like any database management system, is used to manage the
storage and retrieval of data. A relational system differs from other database
management systems in the way the end user or programmer accesses the data.
In a relational database, all data can be treated as two-dimensional tables, sometimes
called relations, consisting of rows and columns, similar in form to a personal computer
spreadsheet. Each row contains pieces of related data such as one employee’s name,
identification number, and salary. Each column contains data of the same type. For
example, one column contains all the employee names; another contains all the
salaries.
When you retrieve data from a table, the result of your operation is returned as
another two-dimensional table. You can therefore perform sophisticated data analysis
by passing the table resulting from one simple operation to another operation,
continuing until the resultant table contains exactly the information you need.
In addition, you can access a whole set of data with a single command. A single SQL
statement can retrieve or modify a set of records matching selection criteria. Thus, it
can often replace several lines of code that read and process one record at a time.
In a relational database, data combined from multiple tables is joined by columns of
common data rather than by links and pointers to physical locations. A relational
database separates the application and the user view of data from the physical
organization and storage of data. Ideally, you can reorganize the physical data storage
without changing existing applications, or you can recombine the data for a new
application by creating a logical view that joins data from multiple tables.
Figure 1-1 shows a relational table that makes data easy to visualize and easy to access.
For example, you can select from the EMPLOYEE table only the rows describing
employees in department 1000 or only the columns containing employee names and
salaries.