Databases Reference
In-Depth Information
Legal compliance to the many data retention laws and regulations is a complicated and expensive process.
For example, the length of time organizations must retain data ranges from two to seven years; for some laws,
the time period is indefinite. The DBA is responsible for ensuring that data processed by DBMSs is retained
in conformance to all laws. Although DBAs need to retain data for legal reasons, they can choose to remove data
that's no longer needed for perfomance reasons.
One solution to data retention is to use what is known as a
data archive
,oran
archive
. In ordinary usage,
an archive (technically
archives
) is a place where public records and documents are kept. A data archive is
similar. It is a place where a record of certain corporate data is kept. In the case of the previously mentioned
completed orders and associated order lines, Figure 8-7 shows how you would remove them from the data-
base and place them in the archive, thus storing them for future reference.
260
DATABASE
Orders
ARCHIVE
OrderNum
OrderDate
CustomerNum
21608
10/20/2007
148
21610
10/20/2007
356
21613
10/21/2007
408
Orders
21614
10/21/2007
282
OrderNum
OrderDate
CustomerNum
21617
10/23/2007
608
21617
10/23/2007
608
21619
10/23/2007
148
21623
10/23/2007
608
OrderLine
OrderNum
PartNum
NumOrdered
QuotedPrice
21608
AT94
11
$21.95
21610
DR93
1
$495.00
21610
DW11
1
$399.99
21613
KL62
4
$329.95
OrderLine
21614
KT03
2
$595.00
OrderNum PartNum NumOrdered QuotedPrice
21617
➞
➞
21617
BV06
2
$794.95
BV06
2
$794.95
21617
CD52
4
$150.00
21617
CD52
4
$150.00
21619
DR93
1
$495.00
21623
KV29
2
$1,290.00
FIGURE 8-7
Movement of order 21617 from the database to the archive
Typically, the DBA stores the archive on some mass storage device—for example, a disk, tape, CD, or DVD.
Whichever medium the DBA uses, the DBA must store copies of both archives and database backups off-
site so that recovery can take place even if a company's buildings and contents are destroyed. The off-site loca-
tion must be a sufficient distance from the main site so that there's no likelihood of a disaster damaging both
sites. Once again, it is up to the DBA to establish and implement procedures for the use, maintenance, and
storage of the archive.
The DBA is also responsible for DBMS evaluation and selection, DBMS maintenance, data dictionary
management, and training.
