Chapter 5- Database Management Systems 18 FIGURE 5.14 Entity Relationship (E-R)
ID: 3737877 • Letter: C
Question
Chapter 5- Database Management Systems 18 FIGURE 5.14 Entity Relationship (E-R) Diagram for Problem 5-7 PURCHASE CLERKS by ORDERS sent to VENDORS order item made by INVENTORYM SHIPMENTS tem PURCHASE ORDERS as: "Purchase orders are sent to vendors. A vendor may receive many (orders, but each purchase order is for only one (1) vendor." c. Redraw Figure 5.14 using Microsoft Visio (or other sofware) his problem asks you to research the literature for applications of intel- ligent systems. Your instructor will guide you regarding the number of pages required for each part Develop a paper that outlines the use of ES in accounting and tax applications. Your paper should describe at least two ES and should describe the benefits and costs of the systems. a. b. Develop a paper that describes how ElS may be implemented (e.g.. using digital dashboards). Include examples (including images) of the systems you find.Explanation / Answer
Answer is as follows:
1)
a) The 7 total table would be make according to given entities, relationships and cardianalities.
5 are the specific entity table.
2 table are used to define M:N relationship between inventory to purchase order and inventory to shipments.
So total are 7 tables there.
b) 2 tables requires a composite primary key.
Purchase order requires the Primary key of inventory to find the order item. So it leads to Composite Primary Key.
Shipments order requires the Primary key of inventory to find the recieved item. So it leads to Composite Primary Key.
c) Composite Priamry keys are the combination of more than one attribute that uniquely identfies the relation in particular table. All Foreign keys also need to include all the columns is composite key.
2)
a) No vendor table does not require any Foreign Key.
b) The reason is that the vendor table has only relation of 1 to N. Instead of 1 side N side needs a foriegn key to implement that. Vendor just sent and make the items. No need to use any typq of foriegn key.
3)
a) Yes there is foriegn key in table inventory.
b) The table inventory have to keep the record of puchased orders and shipped orders. So it needs there primary keys as foriegn key.
4)
a) According to me Inventory table must use Block code as primary key. Because there are multiple types of items and also it have to identify others table like purchase order and Shipments. And provide the details of products from inventory to be easier with block code.
b) According to me Clerk table and Vendors has sequential primary key because they are the Employees or persons who deals with organization and keep the record of all data. To identify the clerks properly you can assign them Sequential Primary key.
c) According to me Shipment table and Purchase Order table have primary key of type Mnemonics. Becasue there are lot of records that are not defined sequentially or as block. So I prefer mnemonic set here.
if there is any query or missing please ask in comments...
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