Distributed database management system

1. Data and Access Control
Presentation of Distributed Database System
Submitted
by
Muhammad Adeel
20M-UOC/CS-54
Submitted to
Mam Haseena Kainat
2
1
Raja Abdullah Arshad
20M-UOC/CS-115

2. • Integrity semantic control refers to the mechanisms and
techniques used to ensure data integrity across multiple
nodes or sites of distributed database. Data integrity
refers to the accuracy, consistency and reliability of data
stored in a database.
• Integrity semantic control involves maintaining various
integrity constraints defined for the database. These
constraints can include entity integrity, referential
integrity, domain integrity and business rules specified
by the database schema and application requirements.
Integrity Semantic Control

3. Techniques
These are some common techniques used for
various integrity constraints.
• Replication: Replicating data across multiple
nodes helps ensure data availability and fault
tolerance. Changes made to data in one node are
propagated to other nodes, maintaining
consistency and integrity.
• Distributed Transactions: It allow multiple
database operations across different nodes to be
treated as a single atomic unit. They ensure that
either all the changes made by a transaction are
committed or none of them, preserving data
integrity.

4. Techniques
• Two Phase Commit: 2PC is a protocol used in
distributed systems to ensure that all
participating nodes agree on the outcome of a
transaction. It guarantees that either all nodes
commit the transaction or they all abort,
preventing partial updates and maintaining data
integrity.
• Distributed Concurrency Control: Concurrency
control mechanisms such as locking and
timestamp ordering, are employed to handle
concurrent access to data across distributed
nodes. These techniques prevent conflicts and
maintain data consistency and integrity during
concurrent transactions.

5. Techniques
• Centralized Control: Some distributed database
systems employ a centralized control
mechanisms where a central authority
coordinates and enforces integrity constraints
across all nodes. This approach ensures a global
view of data integrity but may introduce a
single point of failure.
By employing these techniques and mechanisms,
integrity semantic control helps ensure that the
data stored in a distributed database remains
accurate, consistent and reliable across multiple
nodes, even in the presence of failures, updates
and concurrent access.

6. Centralized Semantic Integrity
Constraints
Integrity constraints a set of rules. It is used to
maintain the quality of data or information.
Integrity constraints ensure that the data insertion,
updating and other processes have to be performed in
such a way that data integrity is not effected.
Types of integrity constraints
• Domain constraints
• Entity integrity constraints
• Referential integrity constraints
• Key constraints

7. Domain Constraints
Domain constraints can be defined as the
definition of a valid set of values for an attribute.
The datatype of domain includes string,
characters, integers, time, date etc. The value of
the attribute must be available in the
corresponding domain.

8. Entity Integrity Constraints
The entity integrity constraints states that primary
key value can’t be null.
• This is because the primary key value is used to
identify individual rows in relation and if the
primary key has a null value, then we can’t
identify those rows.
• A table can contain a null value other than the
primary key field.

9. Referential Integrity Constraints
A refrential integrity constraints is specified
between two tables.

10. Key Constraints
Keys are the entity set that is used to identify
an entity within its entity set uniquely.
• An entity set can have multiple keys, but
out of which one key will be primary key.
• A primary key can contains a unique
value in the relational table.

11. Specifications of Integrity Constraints
Integrity constraints are rules or conditions that
are defined on the attributes or relationships of a
database schema. These constraints are used to
ensure the integrity and validity of data stored in a
database. Here are some common specification of
integrity constraints:
• Entity Integrity Constraint: This constraint specifies
that the primary key of a table must have a unique
value and cannot contain null values.
• Domain Integrity Constraint: This constraint defines
the valid range of values for a specific attribute or
column. It specifies the data type, format and
constraints on the allowed values.
• Referential Integrity Constraint: This constraint
establishes a relationship between two tables based
on a foreign key. It ensures that’s values in the
foreign key column of the referenced table.
• Key Constraint: A key constraint defines the
uniqueness of a set of attributes or columns in a table.
It ensures that the combination of values in the
specified attributes is unique within the table.

12. Specifications of Integrity
Constraints
• Check Constraint: A check constraint defines a
condition that must be satisfied for the values in a
column or combination of columns. It allows you to
satisfy custom conditions that the data must meet.
For example, you can define a check constraint to
ensure that a numeric column only contains positive
values.
• Business Rule Constraint: Business rule constraints
are specific to the requirements and logic of the
application. These constraints are defined based on
the business rules and policies that govern the data.
They ensure that the data adheres to the specific
business requirements.

13. Thank you 😊💗