Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

How does a SqlDataReader handle results from multiple batched SQL statements?

1. By using a DataSet

2. By returning an array of results

3. By enabling NextResult or NextResultAsync methods

4. By issuing separate queries

The correct answer is: By enabling NextResult or NextResultAsync methods

A SqlDataReader processes results from multiple batched SQL statements through the use of the NextResult or NextResultAsync methods. When a batch of SQL commands is executed, the SqlDataReader reads the results one at a time. After reading the results from the first command, the NextResult method can be called to advance to the next result set produced by the subsequent command in the batch. This allows for efficient handling of multiple result sets without the need for multiple separate queries or complex data structures. The ability to use asynchronous versions of these methods enhances performance by allowing an application to remain responsive while waiting for the next result set, especially in scenarios involving I/O-bound operations. This functionality is particularly beneficial in applications that need to handle complex queries or multiple datasets concurrently. In contrast, handling results with a DataSet, returning an array of results, or issuing separate queries would not utilize the SqlDataReader's optimized capability for managing batch results in a single round trip to the database.