Question

Develop an ERD to allow us to keep information on a survey. Suppose a survey will have several questions that can be answered true or false. Over a period of time the survey is conducted and there will be several responses.

Short answer

The ERD includes three main entities ('Survey', 'Question', 'Response') with their attributes, and the relationships between them. Noting that a 'Survey' consists of many 'Questions', and each 'Question' on a 'Survey’ can have multiple 'Responses' is crucial.

Step-by-step solution

Identify Main Entities

The first step is to determine the main entities of the system based on the problem description. In this case, the main entities are: 'Survey', 'Question', and 'Response'.

Identify Attributes

Next, determine the attributes for each entity. For 'Survey': survey ID, date, title could be attributes. For 'Question': question ID, content, survey ID (to indicate which survey the question belongs to) could be its attributes. For 'Response': response ID, respondent ID, survey ID, question ID, answer (True/False) could serve as its attributes.

Determine Relationships

Then, the relationships betwen the entities need determination. A 'Survey' consists of multiple 'Questions’, this is reflected as a one-to-many relationship between these entities. A 'Response' is given by a respondent to a 'Question' in a 'Survey', hence it has relationships with both 'Survey' and 'Question'. These are also one-to-many relationships since a single survey/question can have multiple responses.

Create ERD

Finally, put all these elements together to create the ERD. Entities are represented as rectangles, attributes as ovals, and relationships as diamonds. Make sure to indincate the type of relationship (one-to-one, one-to-many) with the correct notation.

Key concepts

Database Design

Database design is an important concept when creating an effective system for managing and storing data. It involves organizing and structuring a database in a way that allows for efficient retrieval and use of data. In the context of designing a survey system, database design helps to ensure that all the questions and responses are easily manageable.
The process starts with identifying the main entities that need to be captured in the database. Entities are the key components or objects that have distinct roles in the system. For our survey system, these entities include the 'Survey', 'Question', and 'Response'.
This step is followed by determining how these entities relate to each other through relationships. Relationships show how entities depend on and interact with each other. For example, a survey may contain several questions, therefore, establishing a one-to-many relationship between 'Survey' and 'Question'.
Lastly, we represent these entities and their relationships visually through an Entity-Relationship Diagram (ERD). This aids in visualizing how data will be organized in the database, ensuring every piece fits together seamlessly.

Survey System

A survey system is designed to efficiently manage and execute surveys. It involves not only creating and distributing surveys but also collecting and analyzing responses. The system's database architecture is crucial to its functionality.
Each survey has several questions, and these questions must be structured in a way that ensures respondents can easily provide their answers. The survey entity acts as a container that houses several questions.

• Survey: Contains metadata like survey ID, title, and date.
• Question: Needs information such as question ID, content, and often the link to the specific survey it belongs to.
• Response: Captures respondent input, which includes who they are and their answers to each question.

Understanding the survey system allows for better design in collecting uniform and consistent data, ultimately leading to more reliable data analysis.

Entity Attributes

Entity attributes describe the properties or characteristics of an entity in a database. They are crucial for differentiating each entity and tracking specific data points. In our survey system, attributes are essential for uniquely identifying entities and storing relevant information.
For example, a 'Survey' entity might include attributes like survey ID, which is a unique identifier, and title, which provides a brief description. Similarly, a 'Question' might have attributes such as question ID and content. These attributes enable distinguishing one question from another, even within the same survey.
The 'Response' entity attributes are equally pivotal as they store the respondent's input. A response includes response ID, respondent ID, and the actual answer to each question, such as true or false. Essentially, entity attributes provide the necessary details that ensure each piece of data in the survey system is accurately recorded and accessible.