Hey Anurag, the Database Activities Pack enables the user to connect to a database and perform an different actions within it, such as executing transactions or queries and non queries. The Start Transaction activity is a container designed to enable the user to connect to a database, perform multiple actions and then disconnect.
The Connect and Disconnect activities can also be used to connect to a database and consequently disconnect, performing any desired actions with individual connections. The connection process works based on the usage of a DatabaseConnection variable. It is unique for each database you connect to and, once obtained, it can be subsequently used throughout your automation project for connecting to the said database. You can add Database Activities package this way:
Click Manage Packages >> Navigate to Official >> Search for "database" >> Click UiPath.Database.Activities package >> Click Install & Save: