Oracle的同义词(synonyms)从字面上理解就是别名的意思,和试图的功能类似,就是一种映射关系。
创建create public synonym table_name for user.table_name;
删除
drop public synonym table_name;
删除object至回收站
drop table table_name;
彻底删除
DROP TABLE table_name PURGE;
删除回收站内的表
purge table [schema.]table[,[ schema.]table ]...
闪回删除的表
FLASHBACK TABLE[schema.]table[,[ schema.]table ]... TO { TIMESTAMP | SCN } expr [ { ENABLE | DISABLE } TRIGGERS ];
例句
DROP TABLE emp2; SELECT original_name, operation, droptime FROM recyclebin; FLASHBACK TABLE emp2 TO BEFORE DROP;
创建 & 修改directory 语句
CREATE OR REPLACE DIRECTORY directory_name AS '';
赋权限给某用户使用
GRANT READ ON DIRECTORY directory_name TO user_name;
删除directory语句
DROP DIRECTORY directory_name;
CREATE TABLE( , … ) ORGANIZATION EXTERNAL (TYPE DEFAULT DIRECTORY ACCESS PARAMETERS (… ) ) LOCATION (' ') ) REJECT LIMIT [0 | | UNLIMITED];
例句
CREATE TABLE oldemp( fname char(25), lname CHAR(25)) ORGANIZATION EXTERNAL( TYPE ORACLE_LOADER DEFAULT DIRECTORY emp_dir ACCESS PARAMETERS( RECORDS DELIMITED BY NEWLINE NOBADFILE NOLOGFILE FIELDS TERMINATED BY ','( fname POSITION ( 1:20) CHAR, lname POSITION (22:41) CHAR)) LOCATION ('emp.dat')) PARALLEL 5 REJECT LIMIT 200;