Database 2: Here is another database schema concerning World War II capital ships. It involves the following relations: Classes (class, type, country, guns, bore, displacement) Ships (name, class, launched) Battles (name, bdate) Outcomes (ship, battle, result) Ships are built in classes from the same design, and the class is usually named for the first ship of that class. The relation Classes records the name of the class, the type (bb for battleship or bc for battlecruiser), the country that built the ship, the number of main guns, the bore (diameter of the gun barrel, in inches) of the main guns, and the displacement (weight, in tons). Relation Ships records the name of the ship, the name of its class, and the year in which the ship was launched. Relation Battles gives the name and date of battles involving these ships, and relation Outcomes gives the result (sunk, damaged, or ok) for each ship in each battle.

need help with Q11-20.

Key attributes are underlined. The Product relation gives the manufacturer, model number and type (PC aptop, or printer) of various products. The PC relation gives for each model number the CPU speed (in GH2), memory size (in MB), hard disk size (in GB), and the price. The Laptop relation is similar, except that the screen size (in inches) is also included. The Printer relation records for each printer model whether the printer outputs color or not, the printer type (laser or inkjet, etc.), and the price. Sel Database 2: Here is another database schema concerning World War lI capital ships. It involves the following relations: Classes (class, type, country, guns, bore, displacement) Ships (name, class, launched) Battles (name, bdate) Outcomes (ship, battle, result) Eng Ships are built in "classes" from the same design, and the class is usually named for the first ship of that class. The relation Classes records the name of the class, the type ('bb' for battleship or 'bc' for battlecruiser), the country that built the ship, the number of main guns, the bore (diameter of the gun barrel, in inches) of the main guns, and the displacement (weight, in tons). Relation Ships records the name of the ship, the name of its class, and the year in which the ship was launched. Relation Battles gives the name and date of battles involving these ships, and relation Outcomes gives the result (sunk, damaged, or ok) for each ship in each battle. Database 3: Assume a book store has a mail-order database with the following schema of relations: (Primary keys are underlined. Meaning of each attribute is self-explanatory by its name.)