How to Design a Database for Conditional Questioning in Q&A Surveys?

Database Tables and Relationships for Conditional Questioning in Q&A Surveys

Introduction

Designing a survey system that supports conditional questioning can present a challenge in terms of database schema. This article explores the optimal approach for implementing this functionality while maintaining a simple structure.

Database Structure

The base structure proposed includes three main tables:

• Survey: Stores the survey's metadata and general information.
• Question: Represents each individual question within the survey.
• Answer: Captures the user's responses to questions.

Adding Conditionality

To implement conditional questions, we introduce two additional tables:

• QuestionCondition: Links questions with dependencies.
• AnswerOption: Defines the possible answers for a question.

QuestionCondition Table

This table defines the relationships between questions. Each row represents an if-then condition:

• ParentQuestionID: The ID of the question that must be answered in a specific way.
• ChildQuestionID: The ID of the question that should be conditional on the parent question's answer.
• RequiredAnswerOptionID: The ID of the answer option for the parent question that triggers the conditional question.

AnswerOption Table

This table contains:

• QuestionID: The ID of the question to which the answer option belongs.
• AnswerText: The text or value associated with the answer.
• IsConditional: Indicates whether this answer option triggers a conditional question.

Example Usage

Consider a survey with two questions:

• Question A: Do you smoke cigarettes?
• Question B: If yes, what is your favorite cigarette brand?

Using the QuestionCondition table, we can define a rule that says Question B should only be displayed if Question A's answer is "Yes". This is achieved by adding a row with:

• ParentQuestionID = Question A's ID
• ChildQuestionID = Question B's ID
• RequiredAnswerOptionID = The ID of the answer option for Question A that corresponds to "Yes"

Conclusion

The aforementioned database structure provides a flexible and efficient solution for implementing conditional questioning in Q&A surveys. By utilizing the QuestionCondition and AnswerOption tables, we can clearly define the dependencies between questions and present tailored survey experiences to users based on their previous responses.

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