Number of fields in a table and performance

[Kumud]

Is there any limitation on number of fields in a table.
let's say table has 100 fields is it advisable.
Does it degrade performance ?
What affact it will have if table has too many attributes.
(it's datawarehouse and we try to denormalised all dimension).

Any views appriciated.....

[ligang]

I think performance will not be a problem . But Anyway , more columns means the record will occupy more space in the block . So oracle will scan more blocks to search the records . What I want to say is the block size should be set properly if your table has a lot of columns . For example ,
your block is 2K and your table has 100 columns , so because
the row size is rather bigger comparing with block size , the row migration will occurr l.

[nandu]

it's datawarehouse and we try to denormalised all dimension

Kumud

The idea of dimensions is to avoid Denormalization,
Redundancy and is to maintain Referential integrity

The performance depends on the database and Memory structures you use.

ie., if it is Oracle Express Database or Oracle Database and the associated memory structures etc.,

Ligang !


For example , your block is 2K and your table has 100 columns , so because the row size is rather bigger comparing with block size , the row migration will occurr l.


If I am right it will be ROW CHAINING and not ROW MIGRATION !

Cheers
Nandu