1. Session – 8 DATA HANDLING – DISTRIBUTION AND TRANSFORMATION
Matakuliah : M0184 / Pengolahan Data Distribusi
Tahun : 2005
Versi :
Session – 8 DATA HANDLING – DISTRIBUTION AND TRANSFORMATION

2. OBJECTIVES Integration of heterogeneous database systems
Relational database
Processing relational queries against the network database

3. Semantic Approach to the Problem
Optimizing the placement and allocation data without considering the requirements of any quantitative cost model directly
The goal : to split a global database up into fragments to maximize the efficiency of query execution

4. Aggregation
Relationship between entities is represented as a higher level object.
For Example :
An “Appointment” entity could be used to represent a relationship between a Patient, a Doctor and a Clinic.

5. Generalization
A set of similar entities is consider to be a single generic entity
For Example :
A “Person” object could be generalization as a Doctor, a Patient and Nurse entities

6. Restrictions
To obtain a subset of interest give another abstracting mechanism
For example :
The set “Patient” in the Orthopedic department could form an object called “orthopedic patients”

7. Semantic Approach to the Problem Cont’d
Each local data model is defined by the corresponding DDL and DML semantic
To integrate pre-existing heterogeneous database special method of mapping between different data model are needed
We should ideally be able to access all of local data via the global model

8. Getting a relational schema equivalent to network schema
To use relational model, we usually need to provide relational views of the local.
Four source of data in a network schema which have to be used when getting relational :
The record and data item description
The associations between owners and members of set types
The “duplicates not allowed” location mode for record types
The “duplicates not allowed” declaration for set types

9. Processing Relational Query
CUSTOMER
CID
CName
Address
Main-Purchase
Tot-Purchase
PURCHASE
Date
Price
Qty
CUST - PUR
SALESMAN
SID
Sname
Office
Salary
SALE - PUR

10. Processing Relational Query
CUSTOMER : CID, Cname, Address, Main-Purchase, Tot-Purchase
Key : CID
SALESMAN : SID, SName, Office, Salary
Key : SID
PURCHASE : CID, SID, Date, Price, Qty
Key : CID,SID
Foreign Key : CID, SID

11. Processing Relational Query
SELECT SName, Office
FROM CUSTOMER, SALESMAN, PURCHASE
WHERE (Address = “Jakarta”) AND
(Main-Purchase = “Lemari”) AND
(PURCHASE .CID = CUSTOMER.CID)
AND
(PURCHASE .SID = SALESMAN.SID)