jagoodie
asked on
nVarChar to VarChar
1. Is there any script I can write to go through all of my tables to convert all of the nVarChar fields to VarChar?
2. I have found imcomplete info on this, can anyone find concrete: Do indexes on nVarchar perform slower than their VarChar siblings?
3. When I change the type of the field from nVarChar to VarChar, do I need to recreate the index that existed on that field?
Thanks!
2. I have found imcomplete info on this, can anyone find concrete: Do indexes on nVarchar perform slower than their VarChar siblings?
3. When I change the type of the field from nVarChar to VarChar, do I need to recreate the index that existed on that field?
Thanks!
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You can also check this for #2:
http://www.aspfaq.com/show.asp?id=2522
"The key is that implicit conversion *can* cause a table scan instead of an index seek, and on larger tables this can really hurt. While it's important to understand why this happens and in which scenarios, my recommendation is to match your character-based datatypes as explicitly as possible. "
http://www.aspfaq.com/show.asp?id=2522
"The key is that implicit conversion *can* cause a table scan instead of an index seek, and on larger tables this can really hurt. While it's important to understand why this happens and in which scenarios, my recommendation is to match your character-based datatypes as explicitly as possible. "
>> 3. When I change the type of the field from nVarChar to VarChar, do I need to recreate the index that existed on that field? <<
Altering the column should automatically change the index. Performance-wise, you might be better off dropping the index prior to the ALTER and adding it back after the ALTER. The script could be adjusted to do that as well.
Altering the column should automatically change the index. Performance-wise, you might be better off dropping the index prior to the ALTER and adding it back after the ALTER. The script could be adjusted to do that as well.
ASKER
Good stuff. Thanks everyone!
http://www.sql-server-performance.com/datatypes.asp