Your cousin, a senior in high school, asks you to play a Jeopardy-style game with her to help prepare for her computer science exam next week. She gives you these two clues about a type of relational database key: No column values may be NULL, and columns may be combined to create a unique primary key. Which type of key is she referring to

She is referring to composite primary key

Explanation:

Composite primary key comprises of several columns with each having column having its own individual uniqueness.  

In a composite primary, all columns need to have some value as none of them can be null. Also, these individual columns are grouped to get a unique value.  

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