PLSQL中展示游标使用的4个步骤

PLSQL中显示游标使用的4个步骤

本例简单介绍一下游标处理的4个过程中涉及到的加锁,一致性读的问题.

显式游标处理需四个 PL/SQL步骤:

1 定义/声明游标：就是定义一个游标名，以及与其相对应的SELECT 语句。
格式：DECLARE TYPE refcur_type IS REF CURSOR; book_refcur refcur_type ; v_isbn varchar2(100); v_title varchar2(100); BEGIN OPEN book_refcur FOR SELECT ISBN, TITLE FROM BOOKS WHERE rownum<3; FETCH book_refcur INTO v_isbn,v_title; WHILE book_refcur%FOUND LOOP DBMS_OUTPUT.PUT_LINE(v_isbn||': '||v_title); FETCH book_refcur INTO v_isbn,v_title; END LOOP; CLOSE book_refcur; -- open cursoe with another sql statement DBMS_OUTPUT.PUT_LINE('------- open cursoe with another sql statement'); OPEN book_refcur FOR SELECT ISBN, category FROM BOOKS WHERE rownum<3; FETCH book_refcur INTO v_isbn,v_title; WHILE book_refcur%FOUND LOOP DBMS_OUTPUT.PUT_LINE(v_isbn||': category is: '||v_title); FETCH book_refcur INTO v_isbn,v_title; END LOOP; CLOSE book_refcur; END;下面的链接是一个对游标非常完整的解释 http://www.cnblogs.com/huyong/archive/2011/05/04/2036377.html

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