Databases Reference
In-Depth Information
1.3.1 Managing Data Accuracy
Data accuracy
(ensuring that data is accurate and correct) begins with verifying
your source and continues with careful data entry and data manipulation. Most
data management systems provide tools to help ensure data accuracy through
various means, such as establishing relationships between data values and setting
appropriate limits on data values.
During data collection, keep in mind that even though human data sources
are an important resource, they are not always accurate. The information pro-
vided by employees is filtered by the context of the job they perform and the
temptation to put oneself in the best possible light. People often completely
ignore some functions they perform simply because they are too familiar with
their jobs. They might overlook critical steps or leave out details because they
don't seem important. Occasionally, employees at different levels might feel a
need to purposely hide information for various reasons, such as the belief that
doing so will increase the employee's job security (if the employee is the only
one that knows key information, then it's more difficult for the company to fire
him or her).
You need to validate your data sources, as far as is possible. You must some-
times also apply a lifetime to the data, a description of how long the data should
be considered as accurate. This can be a formal designation or more informal,
based a sliding value judgment. Inaccuracies can also arise through poorly
designed algorithms (formulas) used to manipulate data.
1.3.2 Managing Data Security
The term data security is somewhat flexible, depending on the context in which
it is used. Say “data security” to one person, and the first things that come to
mind are protecting the data against unauthorized access and modification. To
someone else, it means making sure that the data is protected against corrup-
tion or loss. Both are critical concerns. In general,
data security
refers to
processes and procedures implemented with the goal of keeping data safe. Basic
data security categories include access security and physical security.
The tools available for ensuring data security are somewhat application- and
platform-specific. This is important because data is a tempting target. Many of
the most destructive viruses, Trojan horses, and other malicious software float-
ing around the Internet right now directly target database applications.
Considering Access Security
Most database systems control
access security
(controlling user and application
access to data) through support of one or more
authentication methods,
which
are ways of verifying a user's identity before allowing access to the data. Differ-
ent levels of access permissions are also provided. For example, you can give a
