Frequently asked questions about databases
Below are some of the more frequently asked questions about databases.
1. What is a database?
An organized collection of information. The assumption is that it is stored
electronically. It could be something as simple as a contact list, with
name and phone number, or as sophisticated as an archive of the New York
Stock Exchange closing prices for the year 2005.
2. What is a data field?
It is the simplest unit of information
(no bits or bytes allowed here) that you, as a user, need to be concerned
with. In a mailing list that contains: Name, Address, City, State and
Zip, each of these elements is a field. A field identifies a specified
property such as the name of the individual. Using a Microsoft Excel spreadsheet
as an example, a field is one of the “blocks” of information.
Name
Jack Jones
3. What is a record?
A record is a collection
of fields. In the Excel spreadsheet example, a record is a horizontal row
(of fields).
| Name |
Address |
City |
State |
Zip |
| Jack Jones |
3 Maple Ave. |
Caldwell |
NJ |
07656 |
4. What is a table?
A collection of records makes up a table.
An example of a table would be all the entries in an Excel spreadsheet
that represent the Names, Addresses, Cities, States, and Zip codes for
all the individuals that you have information on.
| Name |
Address |
City |
State |
Zip |
| Jack Jones |
3 Maple Ave. |
Caldwell |
NJ |
07656 |
| Alan Ant |
54 North St. |
Chicago |
IL |
60611 |
| Bob Blass |
1700 Broadway |
New York |
NY |
10019 |
| Ann Clark |
1144th Street |
Phoenix |
AZ |
85008 |
| Tom Dunn |
55 Cart Rd. |
Monty |
AL |
36117 |
| Ed Edwards |
616 West Point |
Segundo |
CA |
94501 |
5. What is the best way to view a table?
A typical database
file to drive a variable data printing (VDP) application will be a text
file delimited (i.e. fields separated by a comma, tab etc.). It will be
very difficult to visualize the fields in this format, since everything
runs together. It is suggested to open this file in Microsoft Excel software
which will use the delimiter to “block” the
files and organize them in vertical and horizontal alignment. This provides
the best visual depiction of fields, records, and tables.
6. Is that the full hierarchy of a database?
A database could
be as simple as a single table, but it doesn't have to be. There could
be multiple tables that are related to each other in some way. Hence the
term relational database. A single table is often referred to as a “flat” file.
7. So, there are two basic types of databases I may have
to work with in VDP production: simple, single table databases or relational
database?
That's right. Relational databases are used to collect a myriad
of information about something. You could put all of the fields in a single
table, but that could become quite complex and overwhelming when the number
of fields in a record counted into the hundreds. A technique used to keep
the tables simplified (as well as to provide productivity for the computer
program, which isn't required to sort through every field when you are
interested in only a few) is to break them into smaller tables with relational
links. You can quickly get to the data you need without having to process
every bit of information. The science devoted to this is called database
management.
8. What else do I need to know about databases with regard
to VDP production?
Well, there is one more point. A database can either
be single user (i.e. desktop) or multi-user
(i.e. server-based) in its functionality. A server-based, multi-user system
will also have a database management system to provide tools with which
to manipulate the data.
9. Why do I need to know whether I am dealing with a single
user or multi-user database?
It can be helpful information due to the implication
that comes with it. Multi-user systems typically have a database administrator.
This is someone who is skilled at maintaining the database on a day-to-day
basis. They have received formal database management system training. With
a single-user system, the user may have little or no formal training.
10. What are some examples of a single-user database?
Some
of the more commonly used are: Microsoft Access, FileMaker Pro, Paradox,
Lotus, Approach, Fox Pro and ACT!
11. What are some examples of a multi-user database?
Microsoft
SQL Server, Oracle, dBase, Sybase, Informix,DB2 (IBM), Ingres and Coldfusion
12. How do I view a relational database?
Well, it might be
quite complex to look through all the information. You would have to spend
some time understanding the relationships of the tables. A better way to
view the data would be to look at only the data that you were interested
in. This would be a view of the data as a flat file. Even if the data existed
in different tables to begin with. You would want the flat file to contain
only the fields that you were specifically interested in.
13. How would I view, or extract a flat file from a relational
database?
If you were the database administrator, trained in the database
management system (DBMS) in operation, you would perform a query to look
at the data as you wished. You would use tools specific to the DBMS you
were using, or you could use a universal standard language called standard
query language, or SQL (sometimes pronounced “sequel” by
database techies).
14. What is a database management system?
This is a software
tool that allows a database administrator to communicate with the database.
It allows them to create tables, update information, perform queries,
and generate reports. It allows the database administrator to perform day-to-day
tasks.
15. What is a database report?
A database report is a flat
file that contains all the specified information for review. The report
can be formatted and appear as a document to make it easier for the reviewer
to read. Or, a database report is the flat file that contains the fields
that are needed to directly fill the copyholes in the variable data page
(or in conjunction with other fields they allow you to determine the appropriate
content for a copyhole).
16. Okay, I now know about the database report. What else
do I need in order to architect a variable data page?
In addition to the
database report, you will need a variable data template, and possibly,
business rules.
17. Tell me what a variable data template is.
It is a static
page that has been marked up for variable data usage. The areas marked
up are called copyholes. These can be thought of as “holes” in
the page through which different “copy” will be rotated under
the control of the database report. The copyhole can be for text or images
or computer graphics.
18. What are business rules?
Business rules are the conditional
logic that may be needed to “map” the
fields in the database report to the copyholes in the variable data page
template.
For example:
A promotional piece will make one of three offers based on what the targeted
reader currently owns.
If the requirement is to also display an image representative of the new
offering, the image generally wouldn't be able to be identified at the
time of the export from the database. The database would be able to identify
what current products are owned and this would be the data field that would
be exported.
The method to achieve this will vary based on the VDP software you are
using, but this gives a general idea of conditional logic for a simple
business rule.
A business rule to make this work for the copyhole that contains the promotional
image would look something like this (conceptually):
IF current_product = A use Promo_image1
ELSE
IF current_product = B use Promo_image2
ELSE
use Promo_image3
19. How do I go about identifying database
requirements for a variable data job?
It's all about the printed product.
If you've identified the intended audience and what you will use to get
their attention, then the supporting data fields that are required to fill
the copyholes will be identified. You will want data that "maps" to
the copyholes that are on the variable data template. You will need to
check that this information is available from the database and in what
form it exists. If it is not direct (i.e. you have data fields that aren't
exact fits for the copyholes and require some further manipulation), then
you will have to add business rules (i.e. conditional logic) to make it
fit.
20. How will I know what data to mine?
In some cases, you
will have it and you simply need to get it in an organized form. This will
likely be the case for someone who has done a VDP job already, or who has
a good understanding of variable data printing. You should identify what
data you need, establish naming conventions for the fields, and describe
what the content of the fields should look like. A good rule of thumb is
to provide Printing Partners a sample file in advance so we can evaluate
it. This will help you gain an understanding of what types of quality assurance
checks you may need to make on the live data.
21. Who is responsible for data integrity?
Good question.
Make sure that this is discussed in advance. While this is a shared responsibility
if you are providing the data you must assume responsibility for data integrity.
Printing Partners must assume responsibility to explain what it has done
to manipulate the data.
22. Okay, but what if I try to extract a database report
and find out I don't have all the information?
Boom! That's why it is a
good idea to get a sample early on in the project discussion. This will
allow you to adjust the page design to accommodate the information that
is available, or allow you time to script business rules that will manipulate
the data coming in. In any event, it avoids the situation of discovering
there is a data problem when you're on the clock to turn the job around.
23. So, if I understand this correctly, I can provide a database
report by extracting the required information and naming it in a manner
that allows easy identification of the copyhole it is to fill?
That's right.
The better you can communicate what you need to the person responsible
for extracting the data from the database, the less interpretation that
you will have to do on the production end.
24. So, I don't need to be a database expert. I just need
to clearly communicate the information I need to fill the copyholes in
my variable data template?
That's right. And you will know this from your knowledge of the printed
product.
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