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A great deal of research has been focused on the development of database machines. In parallel to this work some vendors have developed general purpose machines with database function built directly into the machine architecture. The IBM AS/400 is one of the principle examples of this approach. Designed with a strong object orientation and the basis functions of the relational database model integrated into it's architecture, the AS/400 has proved to be a commercial success. In the present work we look at the database component of the AS/400.
DB2/400 Database – The Integrated Database
The AS400 contains a relational database called DB2/400. DB2/400 is integrated into the AS/400 partly above the MI and partly in the LIC. Conventional databases are separate software components that reside on top of the operating system. Since DB2/400 is integrated throughout the entire system it can achieve a higher level of efficiency because it is tightly integrated with the components with which it communicates. The database management system (DBMS) is a framework for storing and retrieving data. A DBMS must have an interface so users can access and manipulate the data. There are two interfaces to the AS/400: The Data Description Specifications (DDS) and Structured Query Language (SQL). The DDS, or the native interface, was carried over from the IBM System/38. It has a look and feel similar to IBM’s Information Management System (IMS). The second interface for the AS/400 is SQL. This is the industry standard for relational databases and is an optional product that you must purchase separately.
IBM DB2/400 V4R5 is a relational database management system (RDBMS).
The IBM DB2/400 V4R5 database is integrated with the AS/400 operating system, OS/400. It includes the following features:
Two-Phase Commitment Control
Distributed Relational Database Access (DRDA) Level 2
The database uses SQL/400 as its native interface. SQL/400 includes non-SQL standard facilities such as Command Language (CL) and Data Description Specifications (DDS). These facilities originated with the IBM System/38 and existed before SQL became standard.
Relational Database Access
Much of the operational data stored on OS/390, AS/400, and RS/6000 computers is accessed via a relational database management system. The most popular database on these host systems is IBM DB2. In the case of the AS/400, DB2 is integrated with the operating system.
The underlying structure is traditional (flat) file-based, not table-based.
Can you name any other RDBMS that has these types of bizarre restrictions/work-arounds?
SQL Server doesn't use flat files
certainly doesn't use 10-char internally generated "system names" to manage anything.
I have far more db background than you do
You use the same rule to invalidate Notepad that you said the AS/400 should be excused from!!:
DDS is not a relational capability, no matter how often you repeat and pretend that it is.
Rule 5: The comprehensive data sublanguage rule:
The system must support at least one relational language that
Has a linear syntax
Can be used both interactively and within application programs,
Supports data definition operations (including view definitions), data manipulation operations (update as well as retrieval), security and integrity constraints, and transaction management operations (begin, commit, and rollback).
Rule 12: The nonsubversion rule:
If the system provides a low-level (record-at-a-time) interface, then that interface cannot be used to subvert the system, for example, bypassing a relational security or integrity constraint.
I've taught relational theory,
Rule 5: Comprehensive Data Sublanguage Rule
A relational system may support several languages and various modes of terminal use. How-
ever, there must be at least one language whose statements are expressible, per some
well-defined syntax, as character strings and whose ability to support all of the following is
comprehensible: a. data definition b. view definition c. data manipulation (interactive and
by program) d. integrity constraints e. authorization f. transaction boundaries (begin, com-
mit, and rollback).
On the AS/400, files and tables are too tightly coupled (physical rule violated).
That would not be allowed in a relational system.
Hmm, but isn't a "physical file" on the AS/400 just a "data container", i.e., the underlying data might not be a relational table at all, but some other type of file. Why would DB2 be needed to delete such a non-db file??