Multivalued attribute
A multivalued attribute: a property that can hold several values for one record, such as a person’s phone numbers. On a Chen-style ER diagram it is an oval with a double outline.
Easily confused with
How to read it
A plain Attribute holds one value per record; the double oval says this one may hold a list or set. Textbook examples are the colours of a car, a student’s previous degrees and an instructor’s phone numbers. In Elmasri and Navathe’s text notation the same attribute is written in braces, {Color}. When a diagram becomes a relational database, a multivalued attribute becomes a separate table, one row for each value.
Also searched as: double oval er diagram, multivalued attribute symbol.
Look-alikes
A plain Attribute has a single outline, and a Derived attribute has a dashed one. A double rectangle is a Weak entity, not an attribute. Some designers model the same information as a separate entity with a many-to-many relationship instead of a double oval.
Differences by textbook
In Silberschatz, Korth and Sudarshan’s notation, where attributes are listed inside the entity rectangle, a multivalued attribute is written in that list rather than drawn as a double oval.
Read next
- Next in ER diagram symbolsDerived attributeA derived attribute: a property worked out from other data rather than stored, such as a person’s age from their date of birth. On a Chen-style ER diagram it is an oval with a dashed outline.
- The same shape in AI labels and iconsAI iconAI-generated or AI-changed content. A badge with the letters AI, often in a circle or beside a word such as generated or modified, labels an image, video, sound or text as made or altered with artificial intelligence. The European Union publishes an official set of these icons.
More ER diagram symbols
The same shape elsewhere
Browse symbols drawn with circles or letters and numbers.
Sources
- A Practical Introduction to Databases: 2.2 Entity-relationship diagrams, Christopher Painter-Wakefield, 2022, Runestone Academy, 2.2.2.4 Multivalued attributes
- Data Modeling Using the Entity-Relationship (ER) Model (chapter 3 slides), Ramez Elmasri and Shamkant B. Navathe, Fundamentals of Database Systems, 2016, Pearson, course CS 448, Purdue University, Slides 3-10 and 3-18
- Entity-Relationship Diagram (CMSC 461 lecture notes), Spring 1999, University of Maryland, Baltimore County, Computer Science and Electrical Engineering, Double ellipses
- The Entity-Relationship Model (database systems course notes), Last updated 6 September 2019, Juniata College, Entities and Attributes; Graphical Representation in E-R diagram
- Database System Concepts, 7th edition, chapter 6 slides: Database Design Using the E-R Model, Abraham Silberschatz, Henry F. Korth and S. Sudarshan, db-book.com, Slides 6.21 and 6.41
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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