SA Chapter 10

1. Phase 3: System Design- Data Design บทที่ 10

4. Data Modeling แสดงรายละเอียดของข้อมูลในส่วนของ definition, structure และ relationships ซึ่งไม่สามารถแสดงใน Data flow diagrams และ processing logic techniques ที่เรียนไปแล้วในบทก่อน Data Modeling Data modeling มี 3 ระดับได้แก่ conceptual data model, logical data model และ physical file and database.

7. Sample conceptual data model diagram

11. Top-down perspectives (1)

13. INVOICE includes INVOICE ITEM contain INVENTORY ITEM RECIPE PRODUCT request ORDER places SUPPLIER bills Top-down perspectives (3)

15. INVOICE includes INVOICE ITEM contain INVENTORY ITEM RECIPE PRODUCT request ORDER places SUPPLIER bills Supplier_ID Supplier_Name Supplier_Addr Invoice_No Vendor_ID Invoice_date Paid? Amount_added Item_no Item_desc Stock on hand Minimum order Qty Inventory_level Product_ID Product_desc Order_No Order_date Order_Qty Top-down perspectives (4)

18. Bottom-up perspectives (1) PVF CUSTOMER ORDER ORDER NO: 61384 CUSTOMER NO: 1273 NAME: Contempory Designs ADDRESS: 123 Oak St. CITY STATE:-ZIP: Austin,TX28384 ORDER DATE: 21/01/2006 PROMISED DATE: 31/01/2006 PRODUCT NO. DESCRIPTION QTY_ORDERED UNIT PRICE M128 BookCase 4 200.00 B381 Cabinet 2 900.00 R210 Table 1 500.00

19. Bottom-up perspectives (1) PVF CUSTOMER ORDER ORDER NO: 61384 CUSTOMER NO: 1273 NAME: Contempory Designs ADDRESS: 123 Oak St. CITY STATE:-ZIP: Austin,TX28384 ORDER DATE: 21/01/2006 PROMISED DATE: 31/01/2006 PRODUCT NO. DESCRIPTION QTY_ORDERED UNIT PRICE M128 BookCase 4 200.00 B381 Cabinet 2 900.00 R210 Table 1 500.00

21. ORDER CUSTOMER PRODUCT Order_no Order_date Qty_order Promised_date Unit_price Prod_no Cust_no Prod_desc Cust_name Addr City_state places includes

22. กรณีที่ได้ relations จาก หลาย user interface

31. Steps in Normalization

39. Data Types (2) Data Coding : Pros – reduce storage space - increase integrity (by restricting input to only a few values) Cons – more difficult to users to remember - program must be written to decode fields before display

40. Data Types (3) Data Integrity : The value of foreign key CUSTOMER_ID field within a CUST_ORDER must be limited to the set of CUSTOMER_ID values from the CUSTOMER relations. We would not want to accept an order for a non-existing or unknown CUSTOMER.

41. Data Types (4) Default Value : Null Value Control : - distinct from 0 or blank or any other value - indicate that the value of the field is missing or unknown - ต้องกำหนดว่า field ใดเป็น null ไม่ได้

44. Table Specification Name Description Type Length Value/Range Notes/Remarks Table Name : BankAccount PK : ACCT_NO FK : ACCT_NO เลขที่บัญชี CHAR 7 0-9 Format: nnn-nnnn ธนาคารของลูกค้า Unique Not Null AMOUNT ยอดเงินที่เบิก NUMERIC 5 ,2 0 -10,000 Not Null Must <= BALANCE BALANCE ยอดเงินคงเหลือ ..... ...... ......... ....... ในบัญชี .... ..... .... .... .... ....

51. Business Rules(2) :

53. Designing Control for files

56. Welcome page Product Information Rental Information Product No Verification Product Selection New Product request Rental status Rental history Enter new Product comment View comment Inventory view Rental extension Extension confirmation 0 3 2 2.1 2.2 2.3 3.1 3.2 2.1.1 2.1.2 2.2.1 3.1.1 3.1.1.1 1 1 2 2 2 2.1 2.2 2.1 3 3 3.1 3.1.1 system 1 เมนูหลัก 0