A high-level data model in business or for any functional area is an abstract model that documents and organizes the business data for communication between functional and technical people. It is used to show the data needed and created by business processes.
A data model in software engineering is an abstract model that documents and organizes the business data for communication between team members and is used as a plan for developing applications, specifically how data are stored and accessed.
An entity-relationship model (ERM) is an abstract conceptual data model (or semantic data model) used in software engineering to represent structured data. There are several notations used for ERMs.
1. Use E-R model to get a high-level graphical view of essential components of enterprise and how they are related
2. Then convert E-R diagram to SQL DDL, or whatever database model you are using
E-R Model is not SQL based. It's not limited to any particular DBMS. It is a conceptual and semantic model – captures meanings rather than an actual implementation
The E-R Model: The enterprise is viewed as set of
* Relationships among entities
Symbols used in E-R Diagram
* Entity – rectangle
* Attribute – oval
* Relationship – diamond
* Link - line
Ellipsis (plural ellipses; from the Ancient Greek: ἔλλειψις, élleipsis, "omission" or "falling short") is a series of dots that usually indicate an intentional omission of a word, sentence or whole section from the original text being quoted. An ellipsis can also be used to indicate an unfinished thought or, at the end of a sentence, a trailing off into silence (aposiopesis), example: "But I thought he was . . ." When placed at the beginning or end of a sentence, the ellipsis can also inspire a feeling of melancholy or longing. The ellipsis calls for a slight pause in speech or...