Is it better to use UNIQUE to insert data? is it still highly efficient to query data with count (*) before insertion?

Is it better to use UNIQUE to insert data, or is it more efficient to use count (*) to query data before insertion ?? You cannot insert multiple & nbsp; title & nbsp; + & nbsp; URLs & nbsp; in a table with the same data. Method A: & nbsp; use & nbsp; UNIQUE & nbsp; constraints. you only need to directly execute the statement & nbsp; insert & nbsp; is it better to use UNIQUE to insert data, or is it more efficient to use count (*) to query data before insertion ??
A table cannot insert multiple entries of data with the same title + url.

Method A: use the UNIQUE constraint. the code only needs to directly execute the insert ignore ........

Method B: select count (*) from mytable where title =? And url =?
Insert ....



Which method is more efficient?
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How is the first method highly efficient ......

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Agree to the upstairs, but no tests have been conducted