Erwin datamodeling tool Basics

Erwin datamodeling tool Basics
All Fusion Erwin Data Modeler commonly known as Erwin, is a powerful and leading data modeling tool from Computer Associates. Computer Associates delivers several softwares for enterprise management, storage management solutions, security solutions, application life cycle management, data management and business intelligence.
Erwin makes database creation very simple by generating the DDL(sql) scripts from a data model by using its Forward Engineering technique or Erwin can be used to create data models from the existing database by using its Reverse Engineering technique.
Erwin workplace consists of the following main areas:
1) Logical: In this view, data model represents business requirements like entities, attributes etc.
2) Physical: In this view, data model represents physical structures like tables, columns, datatypes etc.
3)Modelmart: Many users can work with a same data model concurrently.
What can be done with Erwin?
* Logical, Physical and dimensional data models can be created.
* Data Models can be created from existing systems(rdbms, dbms, files etc.).
* Different versions of a data model can be compared.
* Data model and database can be compared.
* SQl scripts can be generated to create databases from data model.
* Reports can be generated in different file formats like .html, .rtf, and .txt.
* Data models can be opened and saved in several different file types like .er1, .ert, .bpx, .xml, .ers, .sql, .cmt, .df, .dbf, and .mdb files.
 By using ModelMart, concurrent users can work on the same data model.
In order to create data models in Erwin, you need to have this All Fusion Erwin Data Modeler installed in your system. If you have installed Modelmart, then more than one user can work on the same model.

What is Data Modeling

What is Data Modeling
A Data model is a conceptual representation of data structures(tables) required for a database and is very powerful in expressing and communicating the business requirements.
A data model visually represents the nature of data, business rules governing the data, and how it will be organized in the database. A data model is comprised of two parts logical design and physical design.
Data model helps functional and technical team in designing the database. Functional team normally refers to one or more Business Analysts, Business Managers, Smart Management Experts, End Users etc., and Technical teams refers to one or more programmers, DBAs etc. Data modelers are responsible for designing the data model and they communicate with functional team to get the business requirements and technical teams to implement the database.
The concept of data modeling can be better understood if we compare the development cycle of a data model to the construction of a house.
For example Company ABC is planning to build a guest house(database) and it calls the building architect(data modeler) and projects its building requirements (business requirements). Building architect(data modeler) develops the plan (data model) and gives it to company ABC. Finally company ABC calls civil engineers(DBA) to construct the guest house(database).
Need for developing a Data Model:
* A new application for OLTP(Online Transaction Processing), ODS(Operational Data Store), data warehouse and data marts.
* Rewriting data models from existing systems that may need to change reports.
* Incorrect data modeling in the existing systems.
* A data base that has no data models.
Advantages and Importance of Data Model
* The goal of a data model is to make sure that all data objects provided by the functional team are completely and accurately represented.
* Data model is detailed enough to be used by the technical team for building the physical database.
* The information contained in the data model will be used to define the significance of business, relational tables, primary and foreign keys, stored procedures, and triggers.
* Data Model can be used to communicate the business within and across businesses.