Databases Reference
In-Depth Information
D
ATA
MIGRATION
REFERS
TO
THE
PROCESS
OF
MIGRATING
OR
TRANSFER-
,
RING
DATA
FROM
ONE
SOURCE
TO
ANOTHER
PERHAPS
REPEATEDLY
OVER
.
THE
Data conversion generally refers to a one-
way movement of data. Data conversion involves several steps, beginning
with data mapping. This involves identifying relationships between data
items in one system to the data items in another system under the context of
two sets of business rules. The quality of the data being converted must
always be determined with extensive user involvement. Data can be cor-
rupted, out of date, or need some sort of translation in the “to be” application.
Data scrubbing is a process used to correct data after it is in the new applica-
tion. Data must be validated by users after conversion through spot inspec-
tions or generated reports.
DURATION
OF
A
LIFECYCLE
Legacy applications that are predominately operating on IBM mainframe
technology support most of the world's data in terms of sheer volume.
With the popularity of new technology architectures, a large amount of this
data must either be converted, migrated, or bridged in future applications.
This section contains the following chapters.
Chapter 38, “Relational Database Conversion: Issues and Approaches,”
examines approaches and issues that must be included in a data conver-
sion framework that focuses on relational databases.
Chapter 39, “Data: Ever Changing and Eternally the Same,” examines
common types of data changes that occur within organizations so that
project teams can focus on finding rules and information that is used to
maintain data integrity over time and through data conversion cycles.
Chapter 40, “A Practical Example of Data Conversion,” looks at opportu-
nities for categorizing data conversions in order to remove much of the
fear, apprehension, and stagnation that face many data conversion
projects. The approach defined in this chapter is iterative, with a strong
emphasis on controls.
Chapter 41, “Data Conversion: Doing It Right the First Time,” describes
problems commonly encountered when converting data. This chapter also
describes steps that can be followed to perform a successful data conver-
sion, and suggests methods for correcting errors that are detected during
the conversion process.
Chapter 42, “Migrating Data to an Integrated Database,” provides an
approach for migrating a collection of files and data sources into a unified data-
base. This chapter provides guidelines for extracting and populating a data-
base, as well as detecting and resolving data inconsistencies after conversion.
Chapter 43, “Bridging Legacy Data and XML,” discusses how dot.com start-
ups can leverage the Extensible Markup Language (XML) to access relational
database management systems (RDBMs) and other legacy data sources.
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