Dynamic form generation using a normalized database

by Ann Bernstein

Twin Cities CFUG

September 1, 2004

MSW Fees Survey: an “e-government” project

Annual survey to find out about fees being assessed by local governments (counties, cities, towns) for solid waste management services.

Our first year as the data collection agency; we want to make a good impression!

Last year we collected other data online and it was very successful

Project Requirements

secure logins for 3,000 potential users (cities, counties, and townships)

users can save data between logins easy to use—some users are inexperienced admin features

Here’s what the survey form looks like:

Tour the web app online...

Two key design considerations:

nearly all data is quantitative content of survey was not finalized when we

began development.

Flat file or normalized database?

We used a flat-file last time. Code was lengthy and repetitive, and therefore prone to bugs.

This time we decided to try something new and use a normalized database.

Here’s a flat-file database

Q1_03 Q2_03 Q3_03 Q4_03 ...Q54_03

Aitkin County

$50 $250

Anoka County

$13,000 $10

Becker County

$250

Flat file issues:

Difficult to query data in separate columns. Structure must be modified every time survey

questions are added/deleted/modified. Lots of empty cells in database.

Here’s a normalized database

UserID Year QuestionID Amount

2 2003 Q1 $250

2 2003 Q7 $45

17 2003 Q1 $2,000

150 2003 Q23 $30

150 2003 Q54 $1,000

Normalized db advantages:

Easy to query Flexible— questions could be modified without

changing structure. Dense data storage Allows for dynamic CF form!

Our final database structure:

Main CF pages used in survey:

1. Initialization page creates 2d array in session variable to store questions and answers.

2. Survey page loops through array to display form questions (and answers, if any exist).

3. Validation page plugs form data into array, checks data, and submits it to database if valid. If not, form redisplays with error highlighted.

Advantages of dynamic form with normalized db

Code is short and sweet. Debugging is much faster because you’re only creating a single form element!

Questions can be added or changed until the last minute.

Data analysis is fast and easy Application is reusable.

Room for improvement (any suggestions?)

2d array is awkward to use.– Hard to read code (what does aryQA[1][7] refer to?)– Index must correspond to key field, so keys must be

kept in perfect sequence.

Admin features were afterthought & klugey Good database design does not necessarily

result in easy coding in CF.

Questions/comments?

Ann Bernstein

(651) 215-0258

ann.bernstein

@moea.state.mn.us