Draw an er diagram with primary key for a farm, Database Management System

Draw an ER diagram that represents the information described below. Show all entity sets, relationship sets, primary keys, and the mapping cardinality of the relationship sets.

"Farmers own one or more sections of land, on which one or many types of grain (e.g., canola, rye, wheat, etc.) may be grown. The grain type can be uniquely identified by its grain ID. As each land section is owned by a single farmer, the farmer knows the amount of each type of grain (measured in tonnes) that is grown in each land section. Based on this information, the farmer can compute the total amount of grains grown in each land section. Each farmer has a name (consists of first name, middle initial, and last name) as well as a unique farmer ID, and may have several contact phone numbers.

When the grains are harvested, each farmer makes a contract to sell some of his grain to a specific grain pool (distribution centre). There are many pools, but each pool handles only one specific type of grain. The price per tonne is constant for each individual pool. There may be multiple pools handling the same type of grain. Normally, a farmer has a contract with a specific pool for a specific amount of a specific type of grain handled by that pool. However, a farmer may have contracts with many pools. Each pool then contracts with a business to sell a specific quantity of grain to that business at an agreed-upon price. This price may vary from contract to contract. A pool may have any number of contracts with any number of businesses, including multiple contracts with the same business. Each pool must maintain the total amount of grain that it has purchased from all of its farmers and the total amount of grain that it has contracted to sell."

Hint: For this question, you may assume the following:

(a) Each land section can be uniquely identified by its section ID. Given a section ID, one can easily find the dimension of the land section.

(b)  One or many types of grain may be grown on the same land section, and the same type of grain may be grown on different land sections.

(c)  Given a grain ID, one can identify the name of the grain type (e.g., canola, rye, wheat, etc.).

(d)  A grain pool (distribution centre) can be uniquely identified by its pool ID.

(e)  Several farmers may have contracts with the same pool.

(f)  A business can be uniquely identified by its business ID.

Posted Date: 2/28/2013 6:17:32 AM | Location : United States







Related Discussions:- Draw an er diagram with primary key for a farm, Assignment Help, Ask Question on Draw an er diagram with primary key for a farm, Get Answer, Expert's Help, Draw an er diagram with primary key for a farm Discussions

Write discussion on Draw an er diagram with primary key for a farm
Your posts are moderated
Related Questions
PART MARKING:  We will only mark TWO of the four questions below but you must submit answers to all four. We will choose the questions we mark randomly and we will supply you with

List the SQL domain Types? SQL supports the following domain types. 1) Char(n) 2) varchar(n) 3) int 4) numeric(p,d) 5) float(n) 6) date.

Given the following relations Vehicle (Reg_no, make, colour) Person(eno, name, address) Owner(eno, reg_no) Write expressions in the relational algebra to answer the following

FDs in Entities : Student entity :                                                Enrolment number →  Student name, Address Course Entity :

Demonstrate the Design of associations During object design phase we must design a strategy to implement associations. Association may be unidirectional or bi-directional. Wha

Heap files (unordered file) Mostly these files are unordered files. It is the easiest and most basic type. These files having of randomly ordered records. The records will have

Explain in detail the consistency model of the distributed file system you studied (GFS or AFS). Present the consistency model chosen and how it was achieved through design. Clarit

A relationship set is a set of relationships of the similar type. For example, let consider the relationship among two entities sets course and student. Collection of all the in

How many levels can be viewed in Architecture of the database ? Architecture of the database can be viewed as three levels.

Describe Specialsation and generalization? Specialisation /generalization: This is a top down and bottom up approach to the design of database. It displays the IS_A relation