Databases Reference
In-Depth Information
Are Spreadsheets Like Databases?
Most people are familiar with some kind of spreadsheet, such as Microsoft
Excel. Spreadsheets are easy and convenient to use, and they may be employed
by an individual much like a database is used in the enterprise. Let's look at the
features of spreadsheets to see how good of a database tool they actually are.
Similar to databases, spreadsheets are commonly used to store information in
a tabular format. A spreadsheet can store data in rows and columns, it can link
cells on one sheet to those on another sheet, and it can force data to be entered in
a specific cell in a specific format. It's easy to calculate formulas from groups of
cells on the spreadsheet, create charts, and work with data in other ways. But there
are many ways in which a spreadsheet is not like a traditional database table:
Spreadsheet
Database
More than one datatype can be stored
in a spreadsheet column.
Usually, only one datatype can be
stored in a database table column.
Cells in a spreadsheet can be defined as
a formula, making the contents variable
depending on other cells.
Columns in a database table have a
fixed value.
A spreadsheet has only the physical
row number to make it unique and no
built-in way to enforce uniqueness of a
given spreadsheet row.
Single rows of a database table are
uniquely identified by a unique value
(typically a primary key, as described
later in this chapter).
Usually, only one user can have write
access to the spreadsheet at any given
time; anyone else is locked out, even if
the second user is on a different part
of the spreadsheet.
Multiple users can access a database
table at the same time, with various
combinations of read and write
capabilities in different parts of the
database.
A spreadsheet does not have any built-
in transaction-control capabilities, such
as ensuring that a group of changes to
the sheet is completely applied or not
applied at all. The Save button is about
the best a spreadsheet can do to
simulate transaction control.
A database usually has transaction-
control capabilities, making it possible
to “roll back” a change if something
happened to prevent it from completing
successfully (such as a power failure).
A corrupt spreadsheet cannot usually
be repaired; the entire spreadsheet
must be restored from a backup,
which may have occurred yesterday,
last week, or never!
There are many tools for repairing and
recovering databases.
