I read in the manual that after mapping the columns, the mapping table gets deleted by itself. So isnt mapping table better then? also, can u tell me why mapping causes slow performance
Join and Mapping are two different things. First you need to think what exactly you need in resulting table. If you want a new column then you require Join . but if you want to update existing column mapping will be needed. Both have their own importance.
Can you give me the example of update?that would be helpful as i am under impression that mapping table is only used add a column to the table like join.
A left join keeps the load optimized. All tested mapping methods BREAK the optimization. This matters. It turns out that a left join is the fastest option for a small number of mapping tables, at least for my sample data (5,000,000 rows, ID field, 10 other fields with values from 0 to 3).
