索引

-- 查询表中有哪些索引并显示具体的状态。
SELECT * FROM USER_INDEXES WHERE TABLE_NAME = UPPER('TABLE_NAME');
-- EG: SELECT STATUS,INDEX_NAME FROM USER_INDEXES WHERE TABLE_NAME = UPPER('TABLE_NAME');

-- 创建索引
CREATE INDEX [INDEX_NAME] ON [TABLE_NAME] (COLUMN_NAME);
-- Eg:
CREATE INDEX INDEX_USERS ON USERS (USER_CODE);

-- 删除索引
DROP INDEX [INDEX_NAME];