Matakuliah
Tahun
Versi
: M0184 / Pengolahan Data Distribusi
: 2005
:
Session – 19
INTEGRATY AND SECURITY
INTEGRITY
OBJECTIVE
• Integrity constraint
• Integrity in centralized database
• Integrity in distributed database
Integrity
• Integrity of a DB is concerned with
consistency, correctness, validity and
accuracy that stated by the rules of
organizational model
• These rules called integrity constraints
Integrity in Centralized Database
Basic integrity constraint
• Relation
• Domain
• Referential
• Explicit
Relation Constraint
• The method used to define relations.
• Example :
CREATE TABLE PATIENT
(
patient# integer NOT NULL,
name varchar (20) NOT NULL,
DOB date,
address varchar(50),
sex varchar(1)
)
Primary key patient#
Primary key must always define with NOT NULL to guarantee the
uniqueness property and no two patient will have the same patient#
DOMAIN Constraint
• Example :
CREATE DOMAIN
patient#
integer
patient# > 0
and
patient# < 10000,
It can be specified : patient# is integer in range 1
to 9999
Referential Integrity
• Example :
PATIENT (patient#, name, DOB, address, sex)
LABREQ (patient#, test-type, date, docter-req)
Laboratory request can be request by patient only
Patient# in LABREQ as a foreign key must have
match in PATIENT table.
Integrity in distributed database
Problem issue around integrity in DDB
• Inconsistencies between local integrity
constraint
• Difficulties in specifying global integrity
constraint
• Inconsistencies between local and global
constraint
Local Integrity Constraint
• Specified and enforced by the local DBMS
and nodal autonomy
• Different rules could apply at different
nodes. So it will make confusion for global
user
Global Integrity Constraint
• Global constraint is necessary to maintain
integrity of a large organizational with
several semi-autonomous department,
each running its own DBMS and managing
its own DB employee
• Global integrity constraint can be stored in
the global schema catalogue and apply at
the global level to global transactions
Inconsistencies between local and
global constraint
• If both local and global constraint are
permit, there must be a way of resolving
inconsistencies between them
• If there’s a strong global control, then it’s
likely global constraint will have priority
• If the DB just participating in a loose
federation with no global control, then local
integrity will dominate