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Questions and Answers
One-to-One - Each instance of one entity relates to only one instance of the ______
One-to-One - Each instance of one entity relates to only one instance of the ______
second
Not frequently used in database systems - Might use to divide a table with many fields in order to isolate part of a ______
Not frequently used in database systems - Might use to divide a table with many fields in order to isolate part of a ______
table
One-to-Many - Each instance of one entity relates to one or more instances of the ______ entity
One-to-Many - Each instance of one entity relates to one or more instances of the ______ entity
second
Most common type of relationship and it is used to relate one record from the ‘primary’ table with many records in the ‘related’ ______
Most common type of relationship and it is used to relate one record from the ‘primary’ table with many records in the ‘related’ ______
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Many-to-Many - Multiple instances of one entity relate to multiple instances of the ______ entity
Many-to-Many - Multiple instances of one entity relate to multiple instances of the ______ entity
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Study Notes
Relationships in Database Systems
- One-to-One relationship: each instance of one entity relates to only one instance of the second entity, not frequently used, and used to divide a table with many fields into smaller parts.
Types of Relationships
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One-to-Many relationship: each instance of one entity relates to one or more instances of the second entity, the most common type of relationship, relating one record in the 'primary' table to many records in the 'related' table, where a parent record in Table A can have many matching child records in Table B, and a child record in Table B has only one matching parent record in Table A.
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Many-to-Many relationship: multiple instances of one entity relate to multiple instances of the second entity.
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Description
Test your knowledge on different types of relationships in databases such as one-to-one and one-to-many. Learn about the characteristics and usage of each relationship type.
