What is the difference between SQLConnection and OLEDBConnection?

Short answer: SqlConnection: Used specifically for connecting to SQL Server databases. OleDbConnection: A more general connection class that can connect to a variety of data sources, such as MS Access, Excel, Oracle, etc.

Example code

Use SqlConnection for SQL Server: SqlConnection sqlConnection = new SqlConnection(connectionString); Use OleDbConnection for Access or other databases: OleDbConnection oleDbConnection = new OleDbConnection(connectionString);

Real-world example (ShopNest)

ShopNest opens a SqlConnection only for the query, then disposes it (using). Connection pooling reuses physical connections automatically.

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.