The Entity Relationship diagram is a graphical representation of the E-R model. The E-R diagram, with the help of various symbols, effectively represents various components of the E-R model. Basically, I Have previous published an SQL Server 2012 and Stored Procedure Video Tutorial you must be a watch that, after that you will understand as well in this post. Furthermore, I have made a video tutorial about Entity Relationship Diagram(ERD) and I have discussed step by step in this tutorial and displayed graphical symbols and explained very well.
I have published Below Complete Graphical Chart with component and details as mentioned, I hope you will understand as well, I have defined very clearly and made the simple graphical chart.
Graphical Symbols and mentioned with details.
A multi-valued attribute is illustrated with a double-line ellipse, which has more than one value for at least one instance of its entity.This attribute may have upper and lower bounds specified for any individual entity value.The telephone attribute of an individual may have one or more values, that is, an individual can have one or more telephone numbers.Hence, the telephone attribute is a multi-valued attribute.The symbol and example of a multi-valued attribute can be seen in the following figure:
A composite attribute may itself contain two or more attributes, which represent basic attributes having independent meanings of their own.The address attribute is usually a composite attribute, composed of attributes such as street, area, and so on. The symbol and example of a composite attribute can be seen in the following figure:
Derived attributes are attributes whose value is entirely dependent on another attribute and are indicated by dashed ellipses. The age attribute of a person is the best example for derived attributes.
For a particular person entity, the age of a person can be determined from the current date and the person’s birth date. The symbol and example of a derived attribute can be seen in the following figure:
Above all about Entity Relationship Diagram, I hope you have understood as well. However, I have made a video tutorial in this topic you can watch my video tutorials and get more ideas about ERD.
Entity Relationship Diagram (ERD)in Urdu
After watching my video tutorial, I hope you have learned it something new. If you like it, kindly share with personal friends, subscribe your email and follow on my website social network pages for post updates. If you have any question / suggestion about this topic to comment me or email me I will reply with your answer about 24 hours. Thanks for the visit and watch my video tutorial.