growing number of regulations, and the need for
companies to be in compliance with them, is
driving the need to retain data for longer
durations. There are many regulations (such as
the Sarbanes-Oxley Act and HIPAA) that govern
how long data must be retained. Indeed, one
analyst group estimates that there are over 150
federal, state and local laws that dictate how
long data must be retained. As such, businesses
of every size have begun to realize that they
must formulate plans for archiving data from
their operational databases.
archiving is component of the larger discipline
of data archiving. Data exists in many formats
and for many purposes, and only a small
percentage of it is actually stored in
databases. Yet even this small proportion
comprises quite a lot of data.
documents, electronic documents, computer files
and data sets, e-mail, and multimedia files are
all examples of data that may reasonably need to
be archived at some point. Each of these
“things” needs to be archived to fulfill
regulatory, legal, and business requirements.
But each type of data requires different
archival processing requirements due to its form
and nature. What works to archive e-mail is not
sufficient for archiving database data, and so
on. In other words, each type of data may need
to command its own technology. This is most
certainly true for database data. Why?
data stored in a database is different than
other types of data in many ways. The main
advantage of using a DBMS is to impose a
logical, structured organization on the data. A
DBMS provides a layer of independence between
the data and the applications that use the data.
In other words, applications are insulated from
how data is structured and stored. The interface
to the data is through the DBMS data language,
whether it is SQL for relational databases, DL/1
for IMS, or even XQuery for XML databases. So
the archival of data from a database requires
knowledge of, and operation in conjunction with,
the mechanisms and interfaces of the DBMS.
we now accept that database archiving is a
subset of data archiving, we need to define
exactly what we mean by the term. Database
archiving is the process of removing
selected data records from operational databases
that are not expected to be referenced again and
storing them in an archive data store where they
can be retrieved if needed.
examine each of the major components of that
last sentence. We say removing
because the data is deleted from the operational
database when it is moved to the data archive.
Consider the lifecycle of a “piece” of data:
upon creation the data is in an operational
state. After a period of time the data is still
needed for reference, but not to drive
operational transactions. After another period
of time it is no longer needed for reference,
but is needed for legal purpose: this is the
archive state. So when data is
archived it can be removed from the operational
say selected records. This is
important because we do not want to archive
database data at the file or table level. We
need only those specific pieces of data that are
no longer needed for operational and reference
purposes by the business. This means that we
must be able to selectively choose particular
pieces of related data for archival… not the
whole database, not an entire table or segment,
and not even a specific row. Instead, all of the
data that represents a business object is
archived at the same time. For example, if we
choose to archive ORDER data, we would also want
to archive the specifics about each ITEM on that
order, as well as CUSTOMER and PRODUCT data.
This data likely spans multiple constructs
within the database.
interesting piece of the definition is this:
and storing them (the data) in an archive
data store. This implies that the data
is stored separately from the operational
database and does not require either the DBMS or
the operational applications to be useful.
Archived data is separate and independent from
any and all production systems from which it was
final component of the definition that warrants
clarification is… where they can be
retrieved if needed. The whole purpose
of archiving is to maintain the data in case it
is required for some purpose. The purpose may be
external, in the form of a lawsuit or to support
a governmental regulation; or internal, in the
form of a new business practice or requirement.
At any rate, the data needs to be readily
accessible in a reasonable timeframe without
requiring a lot of manual manipulation. I mean,
let’s face it, anyone can archive data if they
don’t have to worry about how to query it later,
you have the technology and resources at your
disposal to archive your database data in
accordance with legal requirements?