DBMS CHP 2
ACCESS PROTOCOL
Access control is the procedure by which users are identified and granted
specific privileges to information, systems, or resources.
Access control is the ability to allow or deny the use of a specific resource by a
specific entity.
1. DAC :
DAC is identity-based access control. DAC mechanisms will be controlled by user
identification such as username and password. DAC is discretionary because the owners
can transfer objects or any authenticated information to other users. In simple words,
the owner can determine the access privileges.
Attributes of DAC –
1. Users can transfer their object ownership to another user.
2. The access type of other users can be determined by the user.
3. Authorization failure can restrict the user access after several failed attempts.
4. Unauthorized users will be blind to object characteristics called file size,
directory path, and file name.
Examples- Permitting the Linux file operating system is an example of DAC.
2. MAC :
The operating system in MAC will provide access to the user based on their identities
and data. For gaining access, the user has to submit their personal information. It is very
secure because the rules and restrictions are imposed by the admin and will be strictly
followed. MAC settings and policy management will be established in a secure network
and are limited to system administrators.
Attributes of MAC –
1. MAC policies can help to reduce system errors.
2. It has tighter security because only the administrator can access or alter
controls.
3. MAC has an enforced operating system that can label and delineate incoming
application data.
4. Maintenance will be difficult because only the administrator can have access
to the database.
Examples- Access level of windows for ordinary users, admins, and guests are some of
the examples of MAC.
Role Based Access Control
Role Based Access Control (RBAC), also known as Non discretionary Access
Control, takes more of a real world approach to structuring access control. Access
under RBAC is based on a user's job function within the organization to which the
computer system belongs.
Essentially, RBAC assigns permissions to particular roles in an organization. Users
are then assigned to that particular role. For example, an accountant in a company
will be assigned to the Accountant role, gaining access to all the resources permitted
for all accountants on the system. Similarly, a software engineer might be assigned
to the developer role.
Roles differ from groups in that while users may belong to multiple groups, a user
under RBAC may only be assigned a single role in an organization. Additionally,
there is no way to provide individual users additional permissions over and above
those available for their role. The accountant described above gets the same
permissions as all other accountants, nothing more and nothing less.
Differences between DAC, MAC, and RBAC in ADBMS
Feature
DAC
MAC
RBAC
Definition
User-controlled
Centrallycontrolled
Role-based
Implementation
Permissions on
objects
Security labels
Roles with
permissions
Flexibility
High
Low
Moderate
Security
Low
High
Moderate
Ease of
implementation
Easy
Difficult
Moderate
Management
complexity
Low
High
Moderate
Suitable for
Small
organizations,
collaborative
environments
High-security
environments,
sensitive data
Organizations with
defined roles and
responsibilities
Mobile database
A Mobile database is a database that can be connected to a mobile computing device
over a mobile network (or wireless network). Here the client and the server have
wireless connections. In today’s world, mobile computing is growing very rapidly, and
it is huge potential in the field of the database. It will be applicable on differentdifferent devices like android based mobile databases, iOS based mobile databases, etc.
Common examples of databases are Couch base Lite, Object Box, etc.
Features of Mobile database :



Mobile databases are physically separate from the central database server.
Mobile databases resided on mobile devices.
A mobile database is used to analyze and manipulate data on mobile devices.
Mobile Database typically involves three parties :
1. Fixed Hosts –
It performs the transactions and data management functions with the help of
database servers.
2. Mobiles Units –
These are portable computers that move around a geographical region that
includes the cellular network that these units use to communicate to base
stations.
3. Base Stations –
These are two-way radios installation in fixed locations, that pass
communication with the mobile units to and from the fixed hosts.
Temporal database
A temporal database is a database that needs some aspect of time for the organization of
information. In the temporal database, each tuple in relation is associated with time. It
stores information about the states of the real world and time. The temporal database does
store information about past states it only stores information about current states.
Whenever the state of the database changes, the information in the database gets updated.
In many fields, it is very necessary to store information about past states. For example, a
stock database must store information about past stock prizes for analysis. Historical
information can be stored manually in the schema.
There are various terminologies in the temporal database:


Valid Time: The valid time is a time in which the facts are true with respect to
the real world.
Transaction Time: The transaction time of the database is the time at which
the fact is currently present in the database.

Decision Time: Decision time in the temporal database is the time at which the
decision is made about the fact.
DBMS CHP 3
SERCH INSERT DELETE B PLUS TREE
https://www.javatpoint.com/b-plus-tree
YOUTUBE
B ND B PLUS TREE DIFFERENCE
INDEXING ND TYPES -BOOK,YT
Types of Indexes: Single Level Ordered Indexes; Multilevel Indexes;
https://www.scaler.com/topics/dbms/indexing-in-dbms/
OVERVIEW
https://www.geeksforgeeks.org/difference-between-b-tree-and-b-tree/