YULAIR wrote:
I have no idea what the performance will be if there are frequent
select/replace operations on this table(more than 200 columns which are
almost int(11) type).
If too many columns delays the query, how many is appropriete?
Your table design should not be problematic under normal
circumstances. But the number of columns does not solely determine how
fast your performance will be. There are other elements involved, eg.
a lot depends on how heavy your queries will be, number of records,
indexing... The INT-type plays in your advantage when it comes to
memory use.
Example in my experience: I maintain a table holding ca 130 columns -
not all INT by far - and ca 30.000 records. Heavy queries like joins
perform slower (obviously), but overall speed is reasonable.
PS: There are even MySQL databases with millions of records.
To get an idea of performance, I recommend to:
- make a test table
- put sample data in table, or make script to populate it with lots of
records if you 'll need that in your project
- perform sample queries
- use good indexing methods for faster (optimized) query results
Bart
www.dotinternet.be 
