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'and this constraint create a unique index for accessing the table faster. ' meaning pls?

In the explanation for Primary Key, what does the last line mean - 'and this constraint create a unique index for accessing the table faster. ' Thanks in advance.

15th Aug 2017, 1:32 PM
Abhishek Choudhary
Abhishek Choudhary - avatar
1 ответ
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indexing a column in SQL is like the index at the back of a book, instead of searching the book for a word, you check the index and it gives you the page number. if you search a non indexed column it's like searching through the book and it takes longer.
17th Aug 2017, 6:27 PM
Ralph Landon
Ralph Landon - avatar