Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

What does a SqlDataReader provide when querying a SQL database?

1. A forward-only stream of data

2. Transactional support for data

3. A binary stream of results

4. A strong-typed data structure

The correct answer is: A forward-only stream of data

A SqlDataReader provides a forward-only stream of data when querying a SQL database. This means that as you read rows from the SqlDataReader, you can only move in one direction—from the first row to the last row—without the ability to navigate backward. This design makes the SqlDataReader lightweight and efficient for reading large amounts of data directly from the database without needing to store the results in memory as a collection. The focus on a forward-only nature allows for faster data retrieval, as the SqlDataReader establishes a continuous connection to the database and fetches results in a streamlined manner. This is particularly beneficial when processing data row by row, especially in scenarios involving large datasets, since it minimizes memory overhead. Although there may be options that mention transactional support, binary streams, or strong-typed data structures, these do not accurately represent the primary characteristics of the SqlDataReader. It primarily emphasizes efficient, forward-only access to data streams retrieved from a SQL query.