oracle 给现有表添加自增主键

问题描述

我想向包含数据的现有表添加一个新的自动增量主列.我该怎么做?

I want to add a new auto increment primary column to a existing table which has data. How do I do that?

我首先添加了一列，然后尝试添加一个序列，之后我丢失了如何插入该列并将其设为主键.

I first added a column and then try to add a sequence after that, I lost how to insert and make that column as primary key.

推荐答案

假设你的表被称为 t1 而你的主键被称为 id
首先，创建序列:

Say your table is called t1 and your primary-key is called id
First, create the sequence:

create sequence t1_seq start with 1 increment by 1 nomaxvalue; 

然后创建一个在插入时递增的触发器:

Then create a trigger that increments upon insert:

create trigger t1_trigger
before insert on t1
for each row
   begin
     select t1_seq.nextval into :new.id from dual;
   end;

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