案例十三

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--iot_setup.sql
SET ECHO ON
CREATE TABLE iot_promotions
(
promo_id NUMBER PRIMARY KEY,
promo_name VARCHAR2(40),
promo_subcategory VARCHAR2(30),
promo_category VARCHAR2(30),
promo_cost NUMBER,
promo_begin_date DATE,
promo_end_date DATE
)
ORGANIZATION INDEX;
INSERT INTO iot_promotions
SELECT promo_id, promo_name, promo_subcategory, promo_category, promo_cost, promo_begin_date, promo_end_date FROM promotions;
--query13.sql
SET ECHO ON
SET TIMING ON
SET AUTOTRACE TRACEONLY
@flush.sql
--让优化器决定执行计划,优化器选择的最佳的做法是执行全表扫描
SELECT * FROM promotions WHERE promo_id > 300;
--使用索引
SELECT /*+ INDEX(promotions) */ * FROM promotions WHERE promo_id > 300;
SET TIMING OFF
SET AUTOTRACE OFF
--执行query13.sql
sh@TESTDB11>@query13.sql

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