游标是用来处理使用S E L E C T语句从数据库中检索到的多行记录的工具。借助于游标的功能, 数据库应用程序可以对一组记录逐个进行处理,每次处理一行。例如,下面的程序块可以检索 到数据库中所有学生的名和姓: 节选自在线代码CursorLoop.sql DECLARE v_FirstName VARCHAR2(20); v_LastName VARCHAR2(20); -- Cursor declaration. This defines the SQL statement to -- return the rows. CURSOR c_Students IS SELECT first_name, last_name FROM students; BEGIN -- Begin cursor processing. OPEN c_Students; LOOP -- Retrieve one row. FETCH c_Students INTO v_FirstName, v_LastName; -- Exit the loop after all rows have been retrieved. EXIT WHEN c_Students%NOTFOUND; /* Process data here */ END LOOP; -- End processing. CLOSE c_Students; END;
还有没有更高的见解^_^
数据库应用程序可以对一组记录逐个进行处理,每次处理一行。例如,下面的程序块可以检索
到数据库中所有学生的名和姓:
节选自在线代码CursorLoop.sql
DECLARE
v_FirstName VARCHAR2(20);
v_LastName VARCHAR2(20);
-- Cursor declaration. This defines the SQL statement to
-- return the rows.
CURSOR c_Students IS
SELECT first_name, last_name
FROM students;
BEGIN
-- Begin cursor processing.
OPEN c_Students;
LOOP
-- Retrieve one row.
FETCH c_Students INTO v_FirstName, v_LastName;
-- Exit the loop after all rows have been retrieved.
EXIT WHEN c_Students%NOTFOUND;
/* Process data here */
END LOOP;
-- End processing.
CLOSE c_Students;
END;