Question

Please submit SQL statements as a plain text file (.txt). If blackboard rejects txt file you can submit a zipped file containing the text file. Word, PDF, or Image format are not accepted. You do not need to show screen shot. Make sure you have tested your SQL statements in Oracle 11g.

Problem 1. Please create the following tables for a tool rental database with appropriate primary keys & foreign keys. [30 points]

Assumptions:

1. Each tool belongs to a category.
2. Each category may have a parent category but the parent category should not have parent category (so at most two levels). E.g., a Tool A belongs to electric mower, and electric mower belongs to mower. Mower has no parent category.
3. Each tool can be rented at different time units. The typical time units are hourly, daily, and weekly. There is a different price for each time unit and tool combination. E.g., tool A may be rented at $5 per hour, $30 per day, and $120 per week.
4. Each customer can rent a tool for a certain number of time units. If the tool is returned late a late fee will be charged.

  

The list of tables is:

Tables:

Cust Table:

cid, -- customer id

cname, --- customer name

cphone, --- customer phone

cemail, --- customer email

Category table:

ctid, --- category id

ctname, --- category name

parent, --- parent category id since category has a hierarchy structure, power washers, electric power washers, gas power washers. You can assume that there are only two levels.

Tool:

tid, --- tool id

tname, --- tool name

ctid, --- category id, the bottom level.

quantity, --- number of this tools

Time_unit table allowed renting unit

tuid, --- time unit id

len, --- length of period, can be 1 hour, 1 day, etc.

min_len, --- minimal #of time unit, e.g., hourly rental but minimal 4 hours.

Tool_Price:

tid, --- tool id

tuid, --- time unit id

price, -- price per period

Rental:

rid, --- rental id

cid, --- customer id

tid, --- tool id

tuid, --- time unit id

num_unit, --- number of time unit of rental, e.g., if num_unit = 5 and unit is hourly, it means 5 hours.

start_time, -- rental start time

end_time, --- suppose rental end_time

return_time, --- time to return the tool

credit_card, --- credit card number

total, --- total charge

Answer 1

We are not allowed to attach any file while answering. I can either upload an image or paste the contents. So please find below the SQL statements.

CREATE TABLE cust (
   cid varchar(50) NOT NULL,
   cname varchar(50) NULL,
   cphone varchar(15) NULL,
   cemail varchar(50) NULL,
   CONSTRAINT cust_pk PRIMARY KEY (cid)
);

CREATE TABLE category (
   ctid varchar(50) NOT NULL,
   ctname varchar(50) NULL,
   parent varchar(50) NULL,
   CONSTRAINT category_pk PRIMARY KEY (ctid)
);

CREATE TABLE tool (
   tool_id varchar(50) NOT NULL,
   tname varchar(50) NULL,
   ctid varchar(50) NULL,
   quantity float(10) NULL,
   CONSTRAINT tool_pk PRIMARY KEY (tool_id),
   CONSTRAINT tool_fk FOREIGN KEY (ctid) REFERENCES category(ctid)
);

CREATE TABLE time_unit (
   tuid int NOT NULL,
   len varchar(10) NULL,
   min_len varchar(10) NULL,
   CONSTRAINT time_unit_pk PRIMARY KEY (tuid)
);

CREATE TABLE tool_price (
   tid varchar(50) NOT NULL,
   tuid int NOT NULL,
   price float NULL,
   CONSTRAINT tool_price_fk FOREIGN KEY (tid) REFERENCES tool(tool_id),
   CONSTRAINT tool_price_fk_1 FOREIGN KEY (tuid) REFERENCES time_unit(tuid)
);

CREATE TABLE rental (
   rid int NOT NULL,
   cid varchar(50) NULL,
   tid varchar(50) NULL,
   tuid int NULL,
   num_unit int NULL,
   start_time timestamp NULL,
   end_time timestamp NULL,
   return_time timestamp NULL,
   credit_card int NULL,
   total float NULL,
   CONSTRAINT rental_pk PRIMARY KEY (rid),
   CONSTRAINT rental_fk FOREIGN KEY (cid) REFERENCES cust(cid),
   CONSTRAINT rental_fk_1 FOREIGN KEY (tid) REFERENCES tool(tool_id),
   CONSTRAINT rental_fk_2 FOREIGN KEY (tuid) REFERENCES time_unit(tuid)
);