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Base de données, Tables, Vues, Index et syntaxe SQL
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>>>"Correct" gets the job done. "Efficient" is a different issue.
>>>
>>>Here's an example:
>>>You have a table (Customers) with 1 million rows. There is an index (FullName) on UPPER(LastName + FirstName). What is the "correct" way of finding a particular name? Is it:
>>>
>>>a) LOCATE UPPER(m.LastName + m.FirstName)?
>>>b) SET ORDER TO TAG FullName then SEEK UPPER(m.LastName + m.FirstName)?
>>>c) SEEK(UPPER(m.LastName + m.FirstName), "Customers", "FullName")?
>>>d) SELECT * FROM Customers WHERE UPPER(LastName + FirstName) = UPPER(m.LastName + m.FirstName)?
>>>
>>>Answer is:
>>>All of the above are "correct", but some are more efficient than others.
>>>
>>
>>Then, among the 4 solutions, what is the "correct" choice ?
>>
>
>All are "correct" as they will all get the needed results.
terrible.
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