Question

I have a refresh function. Which will have to compare each row of given data to the database. If it does not exist, insert the new data, else skip it.

But i was wondering, will it be much more efficient i rebuild the whole table of data? Instead of comparing it row by row, i just delete the whole table and insert all the data again?

Which is much more efficient?

Answer 1

For big changes rebuilding the table can be most efficient. But only if you are using truncate table. A “delete from x” without where is likely to be even slower.

The only way to find out where the tipping point is is to measure.

You can only truncate a table if it is not referenced by foreign keys. So you might have to delete/disable the before truncating the table.