What are Cursors and why are they usually discouraged?

Cursors are database objects that allow row-by-row traversal of a result set, similar to iterators in procedural languages.

Reasons they are discouraged:

• They process data one row at a time, leading to poor performance on large sets.
• They often hold locks for a long time, reducing concurrency.
• They introduce complex, procedural logic that is harder to maintain and test.
• They typically have higher memory and tempdb overhead compared to set-based alternatives.

Cursors should be a last resort, used only when set-based solutions are impractical or impossible. In many cases, window functions, MERGE statements, or carefully written set-based updates can replace cursor logic.