Chapter 9: Problem 5

Describe the concept of a cursor and how it is used in embedded SQL.

Short Answer

Expert verified

A cursor in SQL is a database object which manipulates rows from a result set one at a time. It's used in embedded SQL for row-by-row data processing. The cursor usage involves declaring it with a query, opening it to generate a result set, fetching rows one by one, and closing it after all operations are done.

Step by step solution

Definition of a Cursor

A cursor in SQL is a database object which is used to manipulate rows from a result set. It retrieves one row at a time and acts like a pointer, highlighting the current position in a result set.

Purpose of a Cursor

Cursors provide the ability to navigate through the rows of a result set, allowing for row-by-row processing— particularly useful when handling multiple rows but only one at a time.

Using Cursor in Embedded SQL

The usage of cursor in embedded SQL involves several sequential steps. First, declare the cursor with the DECLARE CURSOR statement. The definition includes the SQL query which will retrieve the result set. Second, open the cursor using OPEN statement. This executes the query and generates the result set. After this, FETCH statement is used to retrieve the next row from the result set and move the cursor to the next row. You can continue to fetch rows until no more are available. Once all operations are done, close the cursor with CLOSE statement to free resources.

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Describe the concept of a cursor and how it is used in embedded SQL.

Short Answer

Step by step solution

Definition of a Cursor

Purpose of a Cursor

Using Cursor in Embedded SQL

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