DATA:
A piece of usefull information (ex: phone number of a particular student in a class)
DATABASE:
Database is collection of related data oraganised in a way that data can be easily accessed,managed and updated.
ex: related data of all students ie.,( name,phone no,course,id) which were organised in a table.so that they are easy to access, update,delete
or
It is a place where entire data is stored in a specific order.
DBMS:
A dbms is a software that allows creation,manipulation of database.dbns also provides security to dbms.
ex: ms access is a dbms which allows you to create,manipulate,secure a database
FUNCTIONS OF DBMS:
- provides data independence
- concurrency control
- recovery services
ADAVANTAGES:
- Minimal data duplicay
- easy retrieval of data
- security
- concurrency control
DISADVANTAGES:
- complexity
- costly
- large in size
DATABASE MODEL
A Database model defines the logical design of data. The model describes the relationships between different parts of the data. In history of database design, three models have been in use.
- hierarchical model
- network model
- relational model
HIERARCHICAL MODEL:
In this model each entity has only one parent but can have several children . At the top of hierarchy there is only one entity which is called ROOT
NETWORK MODEL:
In the network model, entities are organised in a graph,in which some entities can be accessed through sveral path
RELATIONAL MODEL:
In this model, data is organised in two-dimesional tables called REALTIONS.
RDBMS
A RDBMS is a DBMS based on relational model introduced by EFF CODD( EFF CODD RULES).In RDBMS data is represented in terms of table which contains rows and columns.
CONTENTS RDBMS:
TABLE:
|
ID
|
STUDENT NAME
|
AGE
|
COURSE
|
|
101F0001
|
MARCUS
|
22
|
ECE
|
|
101F0002
|
SURAJ
|
21
|
CSE
|
|
101F0003
|
MADONY
|
18
|
IT
|
RECORD
|
101F0001
|
MARCUS
|
22
|
ECE
|
FIELD:
ID
|
STUDENT NAME
|
AGE
|
COURSE
|
COLUMN:
|
ID
|
|
101F0001
|
|
101F0002
|
|
101F0003
|
UPCOMING CLASSES
EFF CODD RULES
NORMALIZATION
KEYS IN DBMS
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