Shashwat Shriparv
dwivedishashwat@gmail.com
InfinitySoft
A data model is a model describing the data
in an organization
Abstraction tool
Abstracts essential qualities
of a dataset...
Determination of the data requirements
(views) of individual users & applications
For e.g.
Project building process /custo...
Integration of the individual user (customer)
& application (s/w) views into an overall
conceptual views.
Customer reviews...
The internal structure of the database
Translating the Conceptual Design(previous
steps) into physical structures; basical...
Data abstraction creates hierarchies of
abstractions along 2 dimensions
Aggregation
Generalization
Aggregation
Identifies ...
Generalization
It creates categories into which a data
item may be classified
e.g. Employee can be categorized into
age
Ty...
Conceptual Model:
designed to promote user understandable
Specifications of data.
Physical Model
designed to aid in physic...
Terms used in Data definition
Entity: Any type of "thing" about which info. Is
being maintained.
Attribute: A characterist...
EMPLOYEE is an entity
A person who works for the company is
an instance of EMPLOYEE.
His/her age is an attribute of the en...
Three types amongst activities
recorded during conceptual data modeling.
has adverse effects on the physical
database desi...
Instance of an entity has a given relationship
with only one instance of a 2nd entity.
PROCESSOR
ENDOWED
CHAIR
H
HELD BY
An entity has relationships with many
instances of another entity.
University -> many students
Students -> one university....
An entity has relationships with many
instances of another entity and vice-versa.
STUDENT CLASS
REGISTERED
Defines conditions that must be met for the data
to be complete and correct.
Three types:
 On values
 On dependencies
 ...
Entities and relationships often have
reference conditions that must be met.
A sales order; for an order to exist there mu...
Defines categories of data and their
property.
A schema is an outline or
representation of a plan, a theory, or an
assignm...
Also known as user's schema(appl prg/
person formulating a query) is concerned
with only a small portion of the database
I...
The logical view of the Database
The closest view of the real entities and
their relationships.
Contains integrity rules &...
Describes how the database is organized for
physical storage and access.
Includes information on ordering of records,
bloc...
Translations from one schema to another.
For user access of data
the user view of the data as shown in the
external schema...
Shashwat Shriparv
dwivedishashwat@gmail.com
InfinitySoft
Database model
Database model
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Database model

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Database model

  1. 1. Shashwat Shriparv dwivedishashwat@gmail.com InfinitySoft
  2. 2. A data model is a model describing the data in an organization Abstraction tool Abstracts essential qualities of a dataset Data modeling is the process of abstraction and documentation using a data model
  3. 3. Determination of the data requirements (views) of individual users & applications For e.g. Project building process /customer requirements specs
  4. 4. Integration of the individual user (customer) & application (s/w) views into an overall conceptual views. Customer reviews – Conflict resolution. 2 types: Unconstrained/Natural Conceptual Design Constrained/Conceptual Design
  5. 5. The internal structure of the database Translating the Conceptual Design(previous steps) into physical structures; basically stacks, queues etc…
  6. 6. Data abstraction creates hierarchies of abstractions along 2 dimensions Aggregation Generalization Aggregation Identifies a data items as a part of a higher level, more aggregate descriptor e.g. Project -> Project -> Assignment
  7. 7. Generalization It creates categories into which a data item may be classified e.g. Employee can be categorized into age Type of job Type of pay plan, etc…
  8. 8. Conceptual Model: designed to promote user understandable Specifications of data. Physical Model designed to aid in physical database design. Info logical for human understanding and requirements level. Data logical deals with physical and database implementation. Some models can contain elements of both models.
  9. 9. Terms used in Data definition Entity: Any type of "thing" about which info. Is being maintained. Attribute: A characteristic of an entity. Instance: instance of an entity or relationship. Relationship: Association between entities. Identifiers: Set of attributes which uniquely identify an instance of an entity or relationship.
  10. 10. EMPLOYEE is an entity A person who works for the company is an instance of EMPLOYEE. His/her age is an attribute of the entity type. Employee OF company, here "of" is a relationship. Employee Id is an identifier.
  11. 11. Three types amongst activities recorded during conceptual data modeling. has adverse effects on the physical database design Basically 1:1 1:M M:N
  12. 12. Instance of an entity has a given relationship with only one instance of a 2nd entity. PROCESSOR ENDOWED CHAIR H HELD BY
  13. 13. An entity has relationships with many instances of another entity. University -> many students Students -> one university. UNIVERSITYS1 S2 S3 S4 S5S1 S3S2 S4 S5
  14. 14. An entity has relationships with many instances of another entity and vice-versa. STUDENT CLASS REGISTERED
  15. 15. Defines conditions that must be met for the data to be complete and correct. Three types:  On values  On dependencies  On referential integrity • Values: allowable, valid values for attribute • Dependencies: allowable values for attributes may depend on some other value. • E.g. allowable values for an employee skill classification are a part of allowable skills of the department he/she works in.
  16. 16. Entities and relationships often have reference conditions that must be met. A sales order; for an order to exist there must be a customer.
  17. 17. Defines categories of data and their property. A schema is an outline or representation of a plan, a theory, or an assignment. Classification External (User's view) Conceptual (Overall logic) Internal schema or Data storage Defn.
  18. 18. Also known as user's schema(appl prg/ person formulating a query) is concerned with only a small portion of the database It’s the user view of data being used in the system. Only a very few of the total entities or its attributes are taken into consideration.
  19. 19. The logical view of the Database The closest view of the real entities and their relationships. Contains integrity rules & authorization rules. But no data about how data is stored in the Database.
  20. 20. Describes how the database is organized for physical storage and access. Includes information on ordering of records, block sizes, storage indexes, use of pointers and access strategies being used.
  21. 21. Translations from one schema to another. For user access of data the user view of the data as shown in the external schema must be translated into the overall conceptual schema. This is done by externalconceptual mapping. In the same way conceptualinternal mapping translates logical descriptions of data in the conceptual schema to physical location and access paths in the internal schema.
  22. 22. Shashwat Shriparv dwivedishashwat@gmail.com InfinitySoft

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