To fetch data from the database, we need DB connection. In ADO.Net, based on the Database Provider, there are distinct connection classes. For example, to hook up to an Oracle Database we need to use OracleConnection and in the same way we need SqlConnection to hook up to the SQL Server database. The Command Object is also database specific. For Example, SqlCommand object can talk with SQL Server DB through SqlConnection object and OracleCommand object can talks to the Oracle DB through OracleConnection. These command objects know what needs to be executed in the database. In this article, we will study how to use SqlCommand and its methods ExecuteScalar, ExecuteReader and ExecuteNonQuery.
In this Article, we will use ExecuteScalar function to find the number of records in a table. The article uses employees table from NorthWnd database. But still one can use any table in any database while proceeding through the article.