The document discusses the key components and properties of database management systems (DBMS). It describes the core components as including data models, data structures, query languages, and transaction mechanisms. It notes that transaction mechanisms provide ACID properties like atomicity, consistency, isolation, and durability. The document also outlines important properties of databases like data sharing, data integration, data security, data abstraction, and data independence.

1. Components of DBMS
Properties of DBMS
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Rushdi Shams, Dept of CSE, KUET 1

2. File Processing System
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3. Database Processing System
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4. How DBMS Works
Rushdi Shams, Dept of CSE, KUET 4
SQL PLUS
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ORACLE DBMS
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5. How DBMS Works
Rushdi Shams, Dept of CSE, KUET 5
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6. Components of DBMS
1. Models
 Hierarchical model
 Network model and
 Relational model
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7. Components of DBMS (continued)
2. Data structures
This defines the properties of several
aspects of rows/records and
columns/fields, etc
Rushdi Shams, Dept of CSE, KUET 7

8. Components of DBMS (continued)
3. A query language
allow users to interactively interrogate the
database, analyse its data and update it
according to the user privileges on data
so, you can say query language actually
provides
 Analysis on data
 Interrogation on data
 Security on data
Rushdi Shams, Dept of CSE, KUET 8

9. Components of DBMS (continued)
4. Transaction Mechanism
Transaction means data moving between two
or more databases. It provides ACID property.
In case of database systems, ACID stands for
 Atomicity
 Consistency
 Isolation and
 Durability
Rushdi Shams, Dept of CSE, KUET 9

10. Components of DBMS (continued)
 Atomicity
It is the ability of the DBMS that ensures
either all of the transactions take place or
none of them take place!
Kind of weird, huh? Well, let me give an
example. If a bank account is debited,
another bank account must be credited-
that is called atomicity!
Rushdi Shams, Dept of CSE, KUET 10

11. Components of DBMS (continued)
 Consistency
Every database has some rules according to
the organization to which it belongs. This
property ensures that the databases are in
legal state after a transaction takes place.
For example, if a bank says that its client’s
account balance can never be negative,
then no such transaction will take place that
makes a balance negative.
Rushdi Shams, Dept of CSE, KUET 11

12. Components of DBMS (continued)
 Isolation
This property ensures that no other operation
can intervene the transaction operation.
For example, a bank manager, during a
transaction should be able to see balance of
one account, not on both.
This is the most relaxed option in ACID
properties.
Rushdi Shams, Dept of CSE, KUET 12

13. Components of DBMS (continued)
 Durability
This property ensures that once a
transaction takes place, it cannot be
undone.
when an account to account transfer takes
place, after completion, it should notify the
user that transaction successfully done and
you cannot rewind that!
Rushdi Shams, Dept of CSE, KUET 13

14. Properties of Database
 Data Sharing
 Data Integration
 Data Security
 Data Abstraction
 Data Independence
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15. Data Sharing
 Do you think records are kept to be used by
only one person? Or, should it be shared, so
that we can use it?
Rushdi Shams, Dept of CSE, KUET 15

16. Data Integration
 This implies that a database should be a
collection of data which, at least ideally, has
no redundant data.
 Redundant data is unnecessarily duplicated
data.
 A data value is redundant when an attribute
has two or more identical values.
 A data value is redundant if you can delete
it without information being lost.
Rushdi Shams, Dept of CSE, KUET 16

17. Data Integrity
 The database should accurately reflect the
universe of discourse that it is attempting to
model.
 if relationships exist in the real world
between objects represented by data in a
database then changes made to one
partner in such a relationship should be
accurately reflected in changes made to
other partners in that relationship
Rushdi Shams, Dept of CSE, KUET 17

18. Data Security
 One of the major ways of ensuring the
integrity of a database is by restricting
access – in other words, securing the
database.
 Define a set of authorised users of the
whole, or more usually parts, of the
database.
Rushdi Shams, Dept of CSE, KUET 18

19. Data Abstraction
 An academic database is meant to record
relevant details of university activity. We
say relevant, because no database can store
all the properties of real-world objects. A
database is therefore an abstraction of the
real world
Rushdi Shams, Dept of CSE, KUET 19

20. Data Independence
 If a change is made to some part of the
underlying database, no application
programs using affected data should need
to be changed.
 Also, if a change is made to some part of an
application system then this should not
affect the structure of the underlying data
used by the application.
Rushdi Shams, Dept of CSE, KUET 20