如何实现自定义oracle序列？

oracle序列旨在返回自动递增的数字。我想知道我是否可以实现一个自定义的序列，该序列从我放入的值池中返回，以便我可以告诉序列预期返回的结果。如何实现自定义oracle序列？

无论如何要实施这个？或替代，如添加触发器，或Oracle功能或其他任何东西？

甚至使用表保存价值，但怎么做才是最好的性能，像ORALCE序列

I have this, but not sure is it the best one. 
create table your_table(
    gap_from int, 
    gap_to int 
); 

insert into your_table values(99999, 9998888); 
insert into your_table values(2, 7); 
insert into your_table values(200, 10000); 
insert into your_table values(10001, 300000); 

create table2 as select 
      gap_from, 
      1 + nvl(sum(gap_to - gap_from + 1) over (order by gap_from rows between unbounded preceding and 1 preceding), 0) as seq_from, 
      sum(gap_to - gap_from + 1) over (order by gap_from) as seq_to 
     from your_table; 

create sequence your_new_seq; 


create or replace function get_PK_inside_gap return number as 
    new_seq_val number; 
    PK_inside_gap number; 
begin 
    select your_new_seq.nextval into new_seq_val from dual; 
    execute immediate ' 
    select 
     new_seq_val + gap_from - seq_from 
    from 
     (select :1 as new_seq_val from dual) 
     join (
     table2 
    ) on new_seq_val between seq_from and seq_to' 
    into PK_inside_gap using new_seq_val; 
    return PK_inside_gap; 
end;

来源

2013-03-10 C.c

它可能取决于你想得到什么，你能举个例子吗？ – 2013-03-10 14:28:07

例如，我想开发一个自定义的序列，它返回范围[2,7]，[200,10000]，[10001，300000]，[99999,9998888]等等......所以我想在这里从特定范围获得自动增加。 – 2013-03-10 14:39:06

创建你想要的条目的表格，然后针表在内存中的良好表现。当这些值被“使用”时，您可以更新它们以设置状态标志。

在您对来自内存固定表中的查询中，查询可以选择未被“使用”的最小条目。或者你可以让查询选择其他标准，正如你所说的那样，你需要这种灵活性。

来源

2013-03-10 16:00:12 javadba

从范围5只返回值10：

create sequence seq1 start with 5 maxvalue 10;

为100000只返回值999990，在10跳：

create sequence seq2 start with 100000 maxvalue 999990 increment 10;

来源

2013-03-10 16:08:09

您可以创建通常顺序并修改其根据你的差距清单得出结果。

create table your_table(
    gap_from int, 
    gap_to int 
); 

insert into your_table values(99999, 9998888); 
insert into your_table values(2, 7); 
insert into your_table values(200, 10000); 
insert into your_table values(10001, 300000); 

create sequence your_new_seq; 


create or replace function get_PK_inside_gap return number as 
    new_seq_val number; 
    PK_inside_gap number; 
begin 
    select your_new_seq.nextval into new_seq_val from dual; 
    execute immediate ' 
    select 
     new_seq_val + gap_from - seq_from 
    from 
     (select :1 as new_seq_val from dual) 
     join (
     select 
      gap_from, 
      1 + nvl(sum(gap_to - gap_from + 1) over (order by gap_from rows between unbounded preceding and 1 preceding), 0) as seq_from, 
      sum(gap_to - gap_from + 1) over (order by gap_from) as seq_to 
     from your_table 
    ) on new_seq_val between seq_from and seq_to' 
    into PK_inside_gap using new_seq_val; 
    return PK_inside_gap; 
end;

现在叫get_PK_inside_gap得到不使用PK的您的序列：2,3,4,5,6,7,200,201，...

来源

2013-03-10 16:09:05

哥们我想这可能会帮助你，通常是一旦你创建顺序不能分配开始参数，所以最好放弃该顺序并重新创建;

create or replace 
procedure SEQ_alter(start_with in number,end_with in number,seq_name varchar2) 
    as 
    sql_qury varchar2(148); 
    drop_qury varchar2(148); 
    begin 
    drop_qury:='drop sequence '||seq_name ; 
    execute immediate drop_qury; 
    sql_qury:='create sequence '||seq_name|| ' start with '|| to_number(start_with) ||' maxvalue '|| to_number(end_with); 

    execute immediate sql_qury; 
    end;

来源

2013-03-11 07:39:37

如何实现自定义oracle序列？

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