An Entity is spot, item or thing for which we can gather data.

For example, Student is an Entity  mobile database and we can assortment data like Name, Phone and Address. Here, Name, Phone and Address are the Attributes of element 'understudy'. 

Element Relationship Diagram : 

Additionally called as E-R Diagram. E-R Diagram is the graphical portrayal of the element, its trait and connection between substances. 

[2] Data and Database :