Database Test 3 Computer Subject
Database Test 3 Computer Subject
Question 21
______ express the number of entities to which another entity can be associated via a relationship set.
Mapping cardinality specifies how many instances of one entity type can be associated with instances of another entity type.
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Question 22
An entity in A is associated with at most one entity in B, and an entity in B is associated with at most one entity in A. This is called as _____?
This relationship is one-to-one because each entity in both sets maps to at most one entity in the other set.
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Question 23
An entity in A is associated with at most one entity in B. An entity in B, however can be associated with any number (zero or more) of entities in A. This is called as _____?
This describes a many-to-one relationship from A to B, where many As can link to a single B.
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Question 24
Every weak entity set can be converted into a strong entity set by _____?
Adding the appropriate identifying attributes allows a weak entity to become a strong entity.
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Question 25
In E-R model the details of the entities are hidden from the user. This process is called _____?
Abstraction hides unnecessary entity details from the user, focusing on relevant information.
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Question 26
A collection of related data items, organized for convenient access, is known as _____?
A database organizes related data items for easy storage and retrieval.
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Question 27
A relationship where an entity is related to itself is called _____?
A recursive relationship links an entity to itself in the ER model.
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Question 28
In an ER diagram, the primary key is usually represented by _____?
The primary key is often represented by a bold underline under the attribute name.
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Question 29
In a relational database, each table is also known as _____?
In relational databases, a table is called a relation.
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Question 30
An ER model includes entities, attributes, and _____?
Relationships connect entities in an ER model, alongside entities and attributes.
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