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Many students who study using our platform have reported that a large number of the practice questions here are very similar to those that appear in real exams. View Courses
Many students who study using our platform have reported that a large number of the practice questions here are very similar to those that appear in real exams. View Courses
In a relational database, what is the purpose of a composite key?
The Correct Answer is: A. To combine two or more columns to create a unique identifier for each row
A composite key is made up of two or more columns in a table that together uniquely identify each record. When a single column is not sufficient to ensure uniqueness, combining multiple columns as a composite key guarantees that every row can be uniquely distinguished based on the combination of values. This is important for maintaining data integrity and supporting relationships between tables.
Why the other options are incorrect:
B. To increase data retrieval speed
While keys can improve performance through indexing, the primary purpose of a composite key is to ensure uniqueness, not directly to speed up retrieval.
C. To link tables in a database
Linking tables is usually done with foreign keys, which may reference a composite key, but the composite key itself serves as a unique identifier, not just a link.
D. To encrypt sensitive data
Encryption is unrelated to keys in the context of relational database keys; composite keys have nothing to do with data encryption.
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