MySQL Interviewfragen und Antworten
Frage 16. What Is Row?
A row is a unit of data with related data items stored as one item in one column in a table.
Frage 17. What Is Primary Key?
A primary key is a single column or multiple columns defined to have unique values that can be used as row identifications.
Frage 18. What Is Foreign Key?
A foreign key is a single column or multiple columns defined to have values that can be mapped to a primary key in another table.
Frage 19. What Is Index?
An index is a single column or multiple columns defined to have values pre-sorted to speed up data retrieval speed.
Frage 20. What Is View?
A view is a logical table defined by a query statement.
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