sequence与会话有关--oracle一个比较烂的特性

假如刚刚打开一个会话 ,例如用PL/SQL developer打开一个command窗口

执行一个

SQL> create sequence seq_test_id start with 1;

Sequence created

SQL> select seq_test_id.currval from dual;

select seq_test_id.currval from dual

ORA-08002: sequence SEQ_TEST_ID.CURRVAL is not yet defined in this session

这时会告诉你 sequence SEQ_TEST_ID.CURRVAL is not yet defined in this session

显然SEQ_TEST_ID当前是存在的，而其sequence对象应该也和session无关.

如何解决这个问题 呢 ？？

只需要执行

SQL> select seq_test_id.nextval from dual;

NEXTVAL

----------

1

SQL> select seq_test_id.currval from dual;

CURRVAL

----------

1

原来在查看sequence对象的currval值的时候，必须先要调用它的nextval，实在是没道理的很把，可Oracle就是如此？？

oracle乐于无故增加学习成本阿 /呵呵

只要新打开一个command的窗口，也就会有类似问题，所以记住这个特性就够啦

oracle的错误码也有官方表达

ORA-08002: sequence string.CURRVAL is not yet defined in this session

Cause: sequence CURRVAL has been selected before sequence NEXTVAL

Action: select NEXTVAL from the sequence before selecting CURRVAL

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