What are the performance implications of storing some data across 2
databases instead of duplicating this data in both databases? ie. is
example 1 significantly slower than example 2:
Example 1:
SELECT Users.User.*, Transactions.Sales.date
FROM Users.User, Transactions.Sales
WHERE Users.User.id=Transactions.Sales.userid;
Example 2:
SELECT Users.User.*, Users.Sales.date
FROM Users.User, Users.Sales
WHERE Users.User.id=Users.Sales.userid;
Note in Example 2 the database Users would be significantly larger as
it has data duplicated from the database Transactions.
Thanks for any help.