Explain the use of the Fill method of the DataAdapter.

Short answer: The Fill() method of the DataAdapter is used to populate a DataSet or DataTable with data from the database. It executes the SELECT query defined in the DataAdapter and fills the specified DataSet or DataTable with the results.

Example code

SqlDataAdapter adapter = new SqlDataAdapter("SELECT * FROM Customers", connection); DataSet dataset = new DataSet(); adapter.Fill(dataset, "Customers"); // Fills the DataSet with data from the "Customers" table

Real-world example (ShopNest)

ShopNest’s reporting job still uses ADO.NET for a heavy SQL query where raw performance and stored procedures matter more than EF convenience.

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.