Database Explorer is used to create a database connection and explore its objects. You can drag nodes from the Database Explorer and drop them onto the Model Designer area. This creates new data components that are preconfigured to reference the item dropped.
To access the Database Explorer choose Database Explorer from the View menu or press CTRL+ALT+D.
You can find three buttons on the Database Explorer window. The first one is the Edit Connection Properties 
button. Use it to create a new connection or replace the existing one. The next one is the the Show All Objects 
button. If this button is pressed, current connection in Database Explorer shows objects of all databases or schemas (depending on the provider), otherwise it shows only current database objects. Pressing this button changes these settings for the current connection. The last button is Refresh 
. Use it to synchronize current view with changes that other users might be applying to server.
In the Database Explorer window shortcut menu you can also select the Change View option. You can choose to view the database by objects by selecting Group by Objects, or schemas by selecting Group by Schemas (depending on the provider). The Add To Model option allows to add objects selected in the Database Explorer window to the model. The Add To Model With Related option allows to add a table selected in the Database Explorer window to the model together with objects related to it. The Add To Storage Model option allows to add objects selected in the Database Explorer window to the storage part of the model; note that this option is available for Entity Framework models only.
Database explorer shows all database objects including tables, views, stored procedures and functions. To create model objects, corresponding to the database objects, just select a node and drop it to the Model Designer area.
