A derived attribute is indicated in the Chen notation by a _____ that connects the attribute and an entity.

Question

BlackTom AI · Accepted Answer

In Chen’s ER notation, attributes are drawn as ovals and are connected to their entity rectangle (or relationship diamond) by a line. A derived attribute—one whose value can be computed from other stored attributes (for example, Age derived from BirthDate)—is represented by a dashed (or dotted) oval and is connected to the entity by a dashed line.

Relevant knowledge points and concepts:
- Chen ER components: entity (rectangle), relationship (diamond), attribute (oval).
- Regular (stored) attribute: solid oval connected by a single solid line.
- Derived attribute: an attribute whose value is calculated from other attributes; represented by a dashed/dotted oval and dashed connection.
- Multivalued attribute: depicted as a double (nested) oval, typically connected by a single solid line.
- Double lines or double-dashed lines are not the conventional connectors for attributes in Chen notation (double lines often indicate other semantics like total participation when used between entities and relationships).

Step-by-step reasoning:
1. Identify the attribute type: derived (computed from other data).
2. Recall Chen’s visual conventions: derived attributes use dashed/dotted ovals.
3. The connector between an attribute and its entity follows the same visual style, so a derived attribute’s connector is dashed.
4. Example: Person entity (rectangle) — BirthDate (solid oval, single line) — Age (dashed oval) connected to Person by a dashed line, indicating Age is derived from BirthDate.

Why the correct answer is correct:
- The dashed line explicitly signals the “derived” status in Chen notation, matching the dashed/dotted oval representation and visually distinguishing it from stored attributes.

Why other options are incorrect:
- Single line: denotes a normal (stored) attribute, not derived.
- Double line: not used to indicate an attribute’s derived status (often used elsewhere for different semantics).
- Double dashed line: not a standard Chen convention for attributes.

Conclusion: The connector used is a dashed line, which matches the provided correct answer: dashed line.

A derived attribute is indicated in the Chen notation by a _____ that connects the attribute and an entity.单项选择题

类似问题

Total participation (or mandatory participation) of an entity in a relationship is indicated by:

In which project stage is an entity-relationship (ER) diagram created?

Below is an entity-relationship diagram for a relational database: Which best describes the relationship between customers and sales?

The above ER diagram means that an employee can work for multiple departments, and a department can have at most one employee.

Question at position 28 In the figure below, what is depicted? A one-to-many relationshipA unary relationshipA one-to-one relationshipAn associative entity

Question at position 2 The lines on a ER diagram represent the entities and should be labeled with nouns just like a DFD diagram.TrueFalse

A one-to-many relationship between two entities is symbolized in a diagram by a line that ends with:

In an ER diagram, the weak entity is typically depicted with a ___ _, and the relationship between the weak entity and the strong entity is shown with a _____.

更多留学生实用工具

智能学习助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单