How do I completely overwrite a table with the attribute table of another feature?

[EllenWildig]

I need to update a database of archaeological features by totally overwriting the existing data with a new dataset. I have an attribute table associated to some points which is all of the data I want to appear in the new table. How do I effectively copy and paste this attribute table into the other table, removing all of the entries which already existed?

Also, how do I combine the two tables, so that entries which are contained within both are overwritten, new entries in the attribute table are added to the other and the original table retains all of the other features?

Thanks

[DanPatterson_Retired]

I would recommend making a new file... simply copy the original, delete the fields except for the id and shape fields, perform a join of you new table, id to id as the join key and save the resultant.... it is dangerous by other means

[TimOrmsby]

Note that Ellen wants to keep some attributes from the original feature class--those that don't have equivalents in the updated attribute table. Where there is no update, she wants to keep the existing values; where there is an update she wants to replace the existing values; where the feature is new, she wants to append it. At least that's how I'm reading the second part of her question.

[XanderBakker]

Also the format in which the data is stored and any dependencies will largely influence the best method.