Re: Number of Columns in a table.

I think that the decision whether to store all 900 columns as one row should be made not on the number of columns or length of the row but rather on if the following conditions are true:

All the columns share the same primary key

The row is normalized and none of the columns are really the same value but just for a different unit of measure (sales in Jan, sales in Feb, etc...)

All or a large number of the columns will be used if the row is retrieved. That is some of the columns are used only by financial department, some by warranty, some by manufacturing, etc.... In this case the security rules for accessing the data may need to vary and even if the above two conditions are true so it may make sense to break the row into multiple tables.

None of the columns should be derived from simple calculations on the other columns. [It may be intelligent design to store derived columns where the calculation is complex, time consuming, and frequently retrieved.]

HTH -- Mark D Powell -- Received on Thu Mar 02 2006 - 08:41:28 CST