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What is data modelling
• Advantage of Datamodelling
• Conceptual Data Modelling
• Logical Data Modelling
• Physical Data Modelling
• Tools For Modelling
• Getting Existing Data Model
• Online Training Of Data Modelling
• Links and Resources
What is Data Model ?
Data Model is a blue print for the design of the database.
Data modeling is the process of creating and extending data models which are visual representations of data and its organization.
The ERD Diagram (Entity Relationship Diagram) is the most popular type of data model.
Data models exist at multiple levels including:
• The Conceptual Data Model describes data from a high level. It defines the problem rather than the solution from the business point of view. It includes entities and their relationships. Typically the conceptual data model is developed first.
• The Logical Data Model describes a logical solution to a data project. It provides more details than the conceptual data model and is nearly ready for the creation of a database. These details include attributes, the individual pieces of information that will be included. Typically the logical data model is developed second.
• The Physical Data Model describes the implementation of data in a physical database. It is the blueprint for the database. Typically the physical data model is developed third.
Advantage Of Data Modelling
Why is data model important to a orgonization ?
Reduces development time
Illustrates business practices and ideas
Use data modelling to meet business and performance requirments
Use it for data warehouse projects to make well informed reports
Improve Data performance
Make database easier to use through data modelling
Helps you communicate data models and databse designs to others.
what elements of the data you will store
how large each element can be
what kind of information each element can contain
what elements may be left blank
which elements are constrained to a fixed range
whether and how various tables are to be linked
It shows you the state of busienss
Important tool for communciation.
Information sharing
Enables Competitive advatnage
Maintenance
Proper documentation
In case you go for data integration project or data migration project having a data model eases the process.
Er Modelling was introducted by Chen Before you do data modelling you make an overview of bsuienss data diagram . This shows the overveiw of business And Then you move to
Conceptual data model includes all major entities and relationships and does not contain much detailed level of information about attributes and is often used in the INITIAL PLANNING PHASE.
Conceptual data model is created by gathering business requirements from various sources like business documents, discussion with functional teams, business analysts, smart management experts and end users who do the reporting on the database. Data modelers create conceptual data model and forward that model to functional team for their review.
Conceptual Data Model - Highlights
• Conceptual Data Modelling is the first step in constructing a data model in top-down approach and is
• A clear and accurate visual representation of the business of an organization.
• CDM visualizes the overall structure of the database and provides high-level information
• About the subject areas or data structures of an organization.
• CDM discussion starts with main subject area of an organization and
• then all the major entities of each subject area are discussed in detail.
• CDM comprises of entity types and relationships.
• The relationships between the subject areas and the relationship between each entity in a subject area are drawn by symbolic notation
In CDM discussion, technical as well as non-technical team projects their ideas for building a sound logical data model.
Logical Data Modelling depict the logical entity types, typically referred to simply as entity types,
the data attributes describing those entities, and the relationships between the entities.
showing business entities, and their inter-relationships, names of the relationships and the cardinality
It is more in detailed level and this phase is just before Physicial Data Modelling
It consists of Entity Relation Diagram in a detailed manner..
The physical model is designed for a particular database platform, such as Oracle, SQL Server, Sybase, etc.
A physical data model (a.k.a. database design ) is a representation of a data design which takes into account the facilities and constraints of a given database management system. In the lifecycle of a project it is typically derived from a logical data model , though it may be reverse-engineered from a given database implementation.
A complete physical data model will include all the database artifacts required to create relationships between tables or achieve performance
goals, such as indexes, constraint definitions, linking tables, partitioned tables or clusters.
The physical data model can usually be used to calculate storage estimates and may include specific storage allocation details for a given database system.
• Erwin Marketing Leading data
• Power Desigenr From Sybase
• Visio Microsoft
• Embaracado Er Studio
Why use tools
• They have repository where all users can know the change immediatley
• It supports logical and physical sturcture. It can help change data from logical to physical view.
• Useful for Maintainig standards
• Faster development And Deployment
• Proper Documentation
Some data modelers will apply common data model patterns, Data model patterns describe solutions to common domain issues.
The advantage of patterns
are it can help in rapid application development since time has not to be spent on databsae design.
Below you can see example of databsae patterns
Do you need to see a demo of Data Model Patterns ?
http://www.databaseanswers.org/data%5Fmodels/
Coming Soon
Uk Data Modelling Group -coming soon.