What is the significance of the SqlDataReader?

Short answer: The SqlDataReader is used to retrieve data from the database in a forward-only and read-only manner. It is more efficient than a DataSet when you need to retrieve a large amount of data quickly and do not need to modify the data. It requires an open connection to the database and reads data sequentially, one row at a time.

Example code

SqlCommand command = new SqlCommand("SELECT CustomerName FROM Customers", connection); SqlDataReader reader = command.ExecuteReader(); while (reader.Read()) { Console.WriteLine(reader["CustomerName"]); } reader.Close();

Real-world example (ShopNest)

For large order exports, ShopNest uses SqlDataReader (forward-only, fast). DataSet is heavier and mainly for disconnected editing scenarios.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.