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Chapter 1: What Is IBM Db2? From the Mainframe to Distributed Platforms and the IBM Cloud
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In 1986, SQL became an American National Standards Institute
(ANSI) standard, and in 1987, it became an International
Organization for Standardization (ISO) standard. Over the years,
these standards have been revised to include a larger set of
features; however, despite the existence of standards, RDBMS
vendors often modify the language to some extent. Consequently,
SQL code written for one database may have to be altered—or
completely rewritten—before it can be used with another.
As part of an eort to port the System R prototype to its System/370
mainframe, IBM began work on a new product called DATABASE 2 (or
DB2) in 1980. And, on June 7, 1983, DB2 was made available to a limited
number of customers. Two years later it became generally available to
customers running the Multiple Virtual Storage (MVS) operating system on
System/370 servers.
Thus, IBM Db2 is an RDBMS that is based on Codd’s relational model; it
is a data management system that consists of a set of formally described data
objects that are used to store and link data values by establishing some type
of relationship between them. Typically, data is organized into tables, which
are user-dened objects that present data as a collection of unordered rows
with a xed number of columns. (Each column contains values of the same
data type, and each row contains a set of values for one or more columns;
the representation of a row is called a record, the representation of a column
is called a eld, and the intersection of a row and column is referred to as a
value or cell.) This results in a very ecient way to store data, as values only
have to be stored once: data in tables can be accessed and assembled in a
variety of ways to facilitate any number of operations.
Note: Tables are just one type of object that can
exist in an RDBMS. A Db2 database consists of
many physical and logical components, all of which
aid in the storage, modification, and retrieval of data.
Since its introduction in 1983, new features and functionality have been
added in every new release (and many times, with x packs as well). As
a result, Db2 has become an enterprise-level, high-performant RDBMS
that delivers both the four basic functions of persistent storage (create,
retrieve, update, and delete, or CRUD) and the four properties (atomicity,
consistency, isolation and durability, or ACID) that guarantee data validity,
even when unexpected incidents occur.
From the Mainframe to Distributed Platforms and the IBM
Cloud
In 1987, DB2 arrived on the personal computer (PC) in the form of an
oering called Database Manager, which was one of two special add-on
products that came with the “Extended Edition” version of OS/2 (a new
operating system for PCs that IBM released that same year). A year later,
a version for IBM’s new AS/400 server emerged in the form of SQL/400.
And, by 1992, DB2 had become a standalone product for OS/2 (that was
renamed DB2/2). In 1993, DB2 became available to customers running AIX
on IBM RS/6000 series servers. Initially, this port was known as DB2/6000,
but DB2/2 and DB2/6000 were quickly merged to create a single product
that was christened DB2 for Common Servers. This avor of DB2 arrived
on HP-UX and Solaris servers in 1994, on Windows servers in 1995, and
on Linux servers in 1999. Along the way the name changed yet again (to
DB2 Universal Database or simply DB2 UDB). And, when Version 9 was
made generally available in mid-2006, the “Universal Database” moniker
was replaced with the names of the predominant operating systems the DB2
software ran on, leaving essentially just two avors of DB2: DB2 for z/OS
and DB2 for Linux, UNIX, and Windows (otherwise known as DB2 LUW).
In 2014, IBM launched a fully managed, cloud-based DB2 data
warehouse oering called dashDB, along with a hosted database service
named DB2 on Cloud. And, a fully managed, transactional version of
dashDb named dashDb for Transactions soon followed.
Db2 Today
On June 22, 2017, as part of the release of Version 11.1, Modication
Pack 2, Fix Pack 2 (v11.1.2.2), IBM rebranded all of its DB2 and dashDB
oerings to create the following set of products:
z Db2 (formerly DB2 LUW)
z Db2 for z/OS (formerly DB2 for z/OS)
z Db2 Hosted (formerly DB2 on Cloud)