为oracle主键指定序列编号

在oracle中，为了方便常常用触发器及序列结合起来实现      

先建表、再建序列、然后是触发器，最后测试

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                        create table foo(
                           id number primary key,
                           data varchar2(100));
                         
                        create sequence foo_seq;
                         
                        create or replace trigger bifer_foo_id_pk
                           before insert
                             on foo
                             for each row
                        begin
                           select foo_seq.nextval into :new.id from dual;
                        end;
                        /
                         
                        insert into foo(data)
                           values(‘Chirstopher‘);
                         
                        insert into foo(id,data)
                           values(5,‘Sean‘);
                         
                        select * from foo;