ba - data modeling pptnew

8/3/2019 BA - Data Modeling PPTnew

1/32

Data ModellingData Modelling

Technical Education


2/32

A client sent me a mail for a change in Business process of an ongoing project

The customers in Europe and Middle east can connect to third party transfer services ,

Customers in north America should use old service. ROW will have a new SO

through which existing online bank registered customers will sign up for SO ,

customers with average 10,000 respective currency balance will not have any service

charges other customers service charges depends on country office specifications .

We need to roll out this quickly in US for privileged customers

????


3/32

`Data model

A formal way of representing the data that are usedand created by a business system

Shows the people, places and things about which

data is captured and the relationships among them.`Logical data model

shows the organization of data without indicatinghow it is stored, created, or manipulated.


4/32

` Physical data model shows how the data will actually be stored in

databases or files.

` Normalization is the process analysts use to validate

data models.

` Data models should balance with process models


5/32


6/32

` A picture showing the information created, stored, andused by a business system.

` Entities generally represent similar kinds of information

` Lines drawn between entities show relationshipsamong the data

` High level business rules are also shown


7/32

7 - 7

` Business rules are constraints that are followed whenthe system is in operation.

` ERD symbols can show when one instance of an entity

must exist for an instance of another to exist A doctor must exist before appointments the doctor

can be made


8/32

7 - 8

`ERD symbols can show when one instance of an entitycan be related to only one or many instances ofanother entity

One doctor can have many patients; each patientmay have only one primary doctor

`ERD symbols show when the existence of an entityinstance is optional for a related entity instance

A patient may or may not have insurance coverage


9/32


10/32


11/32

`A person, place, event, or thing about which data iscollected

`Must be multiple occurrences to be an entity

Example: If a firm has only one warehouse, the

warehouse is not an entity. However, if the firm hasseveral warehouses, the warehouse could be an

entity if the firm wants to store data about each

warehouse instance.


12/32

7 - 12


13/32

7 - 13


14/32

7 - 14

` Information captured about an entity

` Only those used by the organization should be

included in the model

` Attribute names are nouns` Sometimes entity name is added at the beginning of

the attribute name for clarity


15/32

`One or more attributes can serve as the entityidentifier, uniquely identifying each entity instance

`Concatenated identifierconsists of several attributes

`An identifier may be artificial, such as creating an IDnumber

` Identifiers may not be developed until the DesignPhase


16/32

7 - 16


17/32

7 - 17


18/32

7 - 18

` Associations between entities

` The first entity in the relationship is the parententity;

the second entity in the relationship is the childentity

` Relationships should have active verb names` Relationships go in both directions


19/32

7 - 19

Cardinalityrefers to the number of times instances in one entitycan be related to instances in another entity

One instance in an entity refers to one and onlyone instance in the related entity (1:1)

One instance in an entity refers to one or moreinstances in the related entity (1:N)

One or more instances in an entity refer to one ormore instances in the related entity (M:N)


20/32

Modality

Refers to whether or not an instance of a child entity

can exist without a related instance in the parent

entity

Not Null means that an instance in the related

entity must exist for an instance in another entity

to be valid

Null means that no instance in the related entityis necessary for an instance in another entity to

be valid


21/32

7 - 21


22/32

Metadata is information stored about components ofthe data model

Metadata is stored in the data dictionary so it can be

shared by developers and users throughout the SDLCA complete, shareable data dictionary helps improve

the quality of the system under development


23/32

An Entity An Attribute A Relationshipcan be can be can bedescribed by: described by: described by:

Name Name Verb phraseDefinition Description Parent entitySpecial Notes Alias Child entityUser Contact Sample Values DefinitionAnalyst Contact Acceptable Values Cardinality

Format ModalityType NotesSpecial Notes


24/32


25/32

` Drawing the ERD is an iterative process of trial andrevision

` ERDs can become quite complex


26/32

` Identify the entities

` Add appropriate attributes for each entity

` Draw the relationships that connect associated entities


27/32

` Identify major categories of information

If available, check the process models for datastores, external entities, and data flows

Check the major inputs and outputs from the usecases

`Verify that there is more than one instance of the entity

that occurs in the system


28/32

` Identify attributes of the entity that are relevant to the systemunder development

Check the process model repository entries for detailson data flows and data stores

Check the data requirements of the requirementsdefinition Interview knowledgeable users Perform document analysis on existing forms and

reports

` Select the entitys identifier


29/32

`Start with an entity and identify all entities with which itshares relationships

`Describe the relationship with the appropriate verb

phrase`Determine the cardinality and modality by discussing

the business rules with knowledgeable users


30/32

`The ERD is the most common technique for drawingdata models. The building blocks of the ERD are:

Entities describe people, places, or things

Attributes capture information about the entity Relationships associate data across entities


31/32

1. BA is not a difficult thing to do in principle

2. It is difficult in practice because it demands provable ANALYSIS which

means TIME AND THINKING on projects these are often both in short

supply

3. So long as the analysis is provable in your method/approach it doesnt matter

what method/approach you use4. Beware the jargon my current fav is Jidoka add the human element to

processes

5. When I am working as a BA my mantra is trust no-one, believe nothing,

prove everything and that should apply to how you do BusinessAnalysis as

well


32/32

ba - data modeling pptnew

Documents