04 February 2011

What are cursors? Explain different types of cursors. What are the disadvantages of cursors?

Cursors allow row-by-row processing of the result-sets.
Types of cursors: Static, Dynamic, Forward-only, Keyset-driven.

Types of cursors: Static, Dynamic, Forward-only, Keyset-driven. See books online for more information.

Disadvantages of cursors: Each time you fetch a row from the cursor, it results in a network roundtrip, where as a normal SELECT query makes only one roundtrip, however large the resultset is. Cursors are also costly because they require more resources and temporary storage (results in more IO operations). Furthere, there are restrictions on the SELECT statements that can be used with some types of cursors.

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