[solved] – Question 93468

We have the following database schema: Computer (vendor, model, machinetype) Model (num, speed, ram, hd, price) Vendor (name, address, phone) Where vendor indicates the manufacturer of a computer, and machine type takes values such as “desktop”, “laptop” and “server”. Underline indicates the primary key. Following inclusion dependencies hold: vendor ⊆ name, and model ⊆ num. Express following queries in relational algebra: A. Find all the vendors who make laptop(s). B. Find the phone numbers of all the vendors who make desktops with speed = 2

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