bulk collect 学习
来源:互联网 发布:js设置div的id 编辑:程序博客网 时间:2024/05/29 08:03
通过bulk collect减少loop处理的开销
采用bulk collect可以将查询结果一次性地加载到collections中。
而不是通过cursor一条一条地处理。
可以在select into,fetch into,returning into语句使用bulk collect。
注意在使用bulk collect时,所有的into变量都必须是collections.
举几个简单的例子:
--在select into语句中使用bulk collect
DECLARE
TYPE SalList IS TABLE OF emp.sal%TYPE;
sals SalList;
BEGIN
-- Limit the number of rows to 100.
SELECT sal BULK COLLECT INTO sals FROM emp
WHERE ROWNUM <= 100;
-- Retrieve 10% (approximately) of the rows in the table.
SELECT sal BULK COLLECT INTO sals FROM emp SAMPLE 10;
END;
/
--在fetch into中使用bulk collect
DECLARE
TYPE DeptRecTab IS TABLE OF dept%ROWTYPE;
dept_recs DeptRecTab;
CURSOR c1 IS
SELECT deptno, dname, loc FROM dept WHERE deptno > 10;
BEGIN
OPEN c1;
FETCH c1 BULK COLLECT INTO dept_recs;
END;
/
--在returning into中使用bulk collect
CREATE TABLE emp2 AS SELECT * FROM employees;
DECLARE
TYPE NumList IS TABLE OF employees.employee_id%TYPE;
enums NumList;
TYPE NameList IS TABLE OF employees.last_name%TYPE;
names NameList;
BEGIN
DELETE FROM emp2 WHERE department_id = 30
RETURNING employee_id, last_name BULK COLLECT INTO enums, names;
dbms_output.put_line('Deleted ' || SQL%ROWCOUNT || ' rows:');
FOR i IN enums.FIRST .. enums.LAST
LOOP
dbms_output.put_line('Employee #' || enums(i) || ': ' || names(i));
END LOOP;
END;
/
DROP TABLE emp2;
采用bulk collect可以将查询结果一次性地加载到collections中。
而不是通过cursor一条一条地处理。
可以在select into,fetch into,returning into语句使用bulk collect。
注意在使用bulk collect时,所有的into变量都必须是collections.
举几个简单的例子:
--在select into语句中使用bulk collect
DECLARE
TYPE SalList IS TABLE OF emp.sal%TYPE;
sals SalList;
BEGIN
-- Limit the number of rows to 100.
SELECT sal BULK COLLECT INTO sals FROM emp
WHERE ROWNUM <= 100;
-- Retrieve 10% (approximately) of the rows in the table.
SELECT sal BULK COLLECT INTO sals FROM emp SAMPLE 10;
END;
/
--在fetch into中使用bulk collect
DECLARE
TYPE DeptRecTab IS TABLE OF dept%ROWTYPE;
dept_recs DeptRecTab;
CURSOR c1 IS
SELECT deptno, dname, loc FROM dept WHERE deptno > 10;
BEGIN
OPEN c1;
FETCH c1 BULK COLLECT INTO dept_recs;
END;
/
--在returning into中使用bulk collect
CREATE TABLE emp2 AS SELECT * FROM employees;
DECLARE
TYPE NumList IS TABLE OF employees.employee_id%TYPE;
enums NumList;
TYPE NameList IS TABLE OF employees.last_name%TYPE;
names NameList;
BEGIN
DELETE FROM emp2 WHERE department_id = 30
RETURNING employee_id, last_name BULK COLLECT INTO enums, names;
dbms_output.put_line('Deleted ' || SQL%ROWCOUNT || ' rows:');
FOR i IN enums.FIRST .. enums.LAST
LOOP
dbms_output.put_line('Employee #' || enums(i) || ': ' || names(i));
END LOOP;
END;
/
DROP TABLE emp2;
0 0
- bulk collect 学习
- Oracle Bulk Collect 学习
- Bulk Collect
- bulk collect
- bulk collect
- bulk collect
- oracle学习之bulk collect用法
- oracle学习之bulk collect用法
- oracle学习之bulk collect用法
- oracle学习之bulk collect用法
- oracle学习之bulk collect用法
- oracle学习之bulk collect用法
- oracle学习之bulk collect用法
- 【转】oracle学习之bulk collect用法
- oracle学习之bulk collect用法
- Oracle学习之BULK COLLECT用法
- oracle学习之bulk collect用法(转)
- oracle学习总结三(bulk collect用法)
- actionbarsherlock导入红叉
- ComboBox绑定到某个数据源的过程中,触发SelectedIndexChanged 事件
- Spring aop中 expression 星号(*)意思
- bleCentralManager 蓝牙透传
- 第6周 Hadoop子项目与Hbase
- bulk collect 学习
- 低分辨率、非对齐、视频监控数据中的人脸识别(LFW, YTF)+CVPR2013
- Charm Bracelet
- hive 结合执行计划 分析 limit 执行原理
- poi 操作excel 2007 设置 字体样式 插入图片
- Surface与SurfaceHolder.Callback
- 解析Unity3D多线程之间的事件派发
- 发布只读访问跨地域冗余存储公共预览版
- hive 执行计划