(1)If CURSOR_SPACE_FOR_TIMEis set to false (the default), then a cursor can be deallocated from the library cache regardless ofwhether application cursors associated with its SQL statement are this case, Oracle Database must verify that the cursor containing the SQLstatement is in the library...
REF CURSOR分两种,Strong REF CURSOR 和 Weak REF CURSOR。 A strong REF CURSOR type specifies a return type, which is the RECORD type of its cursor variables. The PL/SQL compiler does not allow you to use these strongly typed cursor variables for queries that return rows that are not of the...
如果使用 FOR UPDATE 声明游标,则可在DELETE和UPDATE 语句中使用WHERE CURRENT OF cursor_name子句,修改或删除游标结果集合当前行对应的数据库表中的数据行。 例、从EMP表中查询某部门的员工情况,将其工资最低定为 1500; DECLARE V_deptno emp.deptno%TYPE: =&p_deptno; CURSOR emp_cursor IS SELECT empno, sa...
Ifyou have no library cache misses, then you might be able to accelerateexecution calls by setting the value of the initialization parameter CURSOR_SPACE_FOR_TIME to true. This parameter specifieswhether a cursor can be deallocated from the library cache to make room for anew SQL statement. CUR...
delete table_name where current of cursor_name; 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 declare cursor emp_cursor is select ename,sal from emp for update; v_ename emp.ename%type; v_sal emp.sal%tyep; begin open emp_cursor; loop fetch emp_cursor into v_ename,v_oldsal; exit...
同时在你使用update或delete时,必须使用where current of+name_cursor语句,以及在最后记得提交。如果 是级联操作则可以使用for update of 来进行相关表的加锁。 Example1:对职位是PRESIDENT的员工加1000工资,MANAGER的人加500工资 CREATE TABLE emp_new AS SELECT * FROM emp; ...
对于需要带参数的cursor，声明语法如下：示例代码：利用带参数的cursor，将部门号和职称作为参数传递给SELECT语句的WHERE子句。使用FOR UPDATE子句，可以实现锁定特定数据行，避免在处理数据时发生并发冲突。代码演示如下：示例代码：提取在第70号部门工作的员工信息并更新其工资。WHERE CURRENT OF子句用于筛选特定...
Oracle中游标Cursor基本用法详解 查询 SELECT语句用于从数据库中查询数据,当在PL/SQL中使用SELECT语句时,要与INTO子句一起使用,查询的 返回值被赋予INTO子句中的变量,变量的声明是在DELCARE中。SELECT INTO语法如下: SELECT [DISTICT|ALL]{*|column[,column,…]}...
使用 WHERE CURRENT OF子句来引用显式cursor的当前行 语法：WHERECURRENTOFcursor;代码演示 ：将所有保安...
Oracle 游标Cursor 的基本用法 查询 SELECT语句用于从数据库中查询数据,当在PL/SQL中使用SELECT语句时,要与INTO子句一起使用,查询的 返回值被赋予INTO子句中的变量,变量的声明是在DELCARE中。SELECT INTO语法如下: SELECT [DISTICT|ALL]{*|column[,column,...]}...