MySQL 面试题与答案
Test your skills through the online practice test: MySQL Quiz Online Practice Test
问题 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.
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问题 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.
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问题 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.
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问题 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.
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问题 20. What Is View?
A view is a logical table defined by a query statement.
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