1. Use the Management Studio to create a new database called MyWebDB using the default settings. (If the database already exists, use the Management Studio to delete it and then recreate it.) 2. Use the Management Studio to create the following tables and relationships.
3. Define the UserID column in the Users table, the ProductsID column in the Products table, and the DownloadID column in the Downloads table as primary keys and identity columns.
4. In the Downloads table, set the UserID and ProductID column as the foreign keys. Ensure the Tables and Columns Specification section is expanded in screenshot.
5. Define the columns so none of them allow null values.
6. Use the Management Studio to create indexes for the foreign keys in the Downloads table.
7. Use the Management Studio to create a unique index on the EmailAddress and ProductName columns and a regular index on the DownloadDate column.

The idea that, for each pair of devices v and w, there’s a strict dichotomy between being “in range” or “out of range” is a simplified abstraction. more accurately, there’s a power decay function f (·) that specifies, for a pair of devices at distance δ, the signal strength f(δ) that they’ll be able to achieve on their wireless connection. (we’ll assume that f (δ) decreases with increasing δ.) we might want to build this into our notion of back-up sets as follows: among the k devices in the back-up set of v, there should be at least one that can be reached with very high signal strength, at least one other that can be reached with moderately high signal strength, and so forth. more concretely, we have values p1 ≥ p2 ≥ . . ≥ pk, so that if the back-up set for v consists of devices at distances d1≤d2≤≤dk,thenweshouldhavef(dj)≥pj foreachj. give an algorithm that determines whether it is possible to choose a back-up set for each device subject to this more detailed condition, still requiring that no device should appear in the back-up set of more than b other devices. again, the algorithm should output the back-up sets themselves, provided they can be found.\