The dashboard is a graphical representation of a report. It will show data from the source report as a graphical component, which can be a metric chart, gauge, donut chart, and so on. Components provide a glimpse of the key metrics and performance meters of your organization. Use this when you are interested in knowing about the numbers and comparisons based on the same fields.
A user will be able to see all the details in a dashboard whether they have access to the records or not; however, once they drill down to the report, they will only be able to see records that he or she has access to. Dashboard components can be a metric chart, gauge, donut chart, table, or another component that you can create with Visualforce. A description of each component is as follows:
Chart: You can use a chart when you want to display data graphically. It also allows you to choose from a variety of chart types.
Gauge: You can use a gauge when you have a single value that...