Fil: Ei Vi Windom Helo Home Tools sign In Database 2: Here is another database s

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Fil: Ei Vi Windom Helo Home Tools sign In Database 2: Here is another database schema concerning World WarI 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) Comvat to Dcc.ment Lanqusg: Englsh us) Change 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 Convert Create PDF Comment Combine Files v EOrgize Pages 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.) Protet Rodact rill &Sig; Employees (Eno, Ename, Hire Date; Books (Isbn, Bname, Quantity, Price); Customers (Cno, Cname, Street, Zip, Phone); Orders (Ono, Cno, Eno, Received, Shipped); Orderline (Ono, Isbn, Qty); Zipcodes (Zip, City, State); Send for Signature . Send & Track More 10015 nd share files in Lesm More E O lype here to search

Explanation / Answer

Primary key is the key that uniquely identifies a tuple in the relation.

Foreign key is the primary key of some table present in another table. It is used for joining tables.

Database 2: Consist of the following tables:

Classes table with attributes : class (primary key) , type , country , guns, bore , displacement

Ships table with attributes : name(primary key) , class(foreign key of Classes table) , launched

Battles table with attributes : name(primary key) , bdate

Outcomes table with attributes : ship(foreign key of Ships table) , battle(foreign key of Battle table) , result . The primary key of Outcomes table is the combination of ship and battle i.e primary key(ship,battle)

Database 3: Consist of the following tables:

Employees table with attributes : Eno(primary key) , Ename, Hire_Date

Books table with attributes : Isbn(primary key) , Bname , Quantity , Price

Customers table with attributes : Cno(primary key) , Cname, Street , Zip(foreign key of Zipcodes table) , Phone

Orders table with attributes : Ono(primary key) , Cno(foreign key of Customers table) , Eno(foreign key of Employees table) , Received , Shipped

Orderline table with attributes : Ono(foreign key of Orders table) , Isbn(foreign key of Books table) , Qty . Combination of Ono and Isbn is the primary key of Orderline table i.e primary key(Ono,Isbn)

ZipCodes table with attributes : Zip(primary key) , City , State

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