在Oracle中似乎没有AUTO_INCREMENT的概念,直到并且包括版本11g。
如何在Oracle 11g中创建一个行为像自动递增的列?
在Oracle中似乎没有AUTO_INCREMENT的概念,直到并且包括版本11g。
如何在Oracle 11g中创建一个行为像自动递增的列?
当前回答
create trigger t1_trigger
before insert on AUDITLOGS
for each row
begin
select t1_seq.nextval into :new.id from dual;
end;
我只需要改变表名(AUDITLOGS)与你的表名和新的。使用new.column_name标识
其他回答
Oracle数据库12c引入了Identity,一个自动增量(系统生成)列。 在以前的数据库版本中(直到11g),您通常通过创建Sequence和Trigger来实现Identity。 从12c开始,您可以创建自己的Table并定义必须作为Identity生成的列。
在甲骨文12c以后,你可以这样做,
CREATE TABLE MAPS
(
MAP_ID INTEGER GENERATED ALWAYS AS IDENTITY (START WITH 1 INCREMENT BY 1) NOT NULL,
MAP_NAME VARCHAR(24) NOT NULL,
UNIQUE (MAP_ID, MAP_NAME)
);
在Oracle (Pre 12c)中。
-- create table
CREATE TABLE MAPS
(
MAP_ID INTEGER NOT NULL ,
MAP_NAME VARCHAR(24) NOT NULL,
UNIQUE (MAP_ID, MAP_NAME)
);
-- create sequence
CREATE SEQUENCE MAPS_SEQ;
-- create tigger using the sequence
CREATE OR REPLACE TRIGGER MAPS_TRG
BEFORE INSERT ON MAPS
FOR EACH ROW
WHEN (new.MAP_ID IS NULL)
BEGIN
SELECT MAPS_SEQ.NEXTVAL
INTO :new.MAP_ID
FROM dual;
END;
/
oracle在12c中有序列和标识列
http://www.oracle-base.com/articles/12c/identity-columns-in-oracle-12cr1.php#identity-columns
我发现了这个,但不确定rdb7是什么 http://www.oracle.com/technetwork/products/rdb/0307-identity-columns-128126.pdf
FUNCTION GETUNIQUEID_2 RETURN VARCHAR2
AS
v_curr_id NUMBER;
v_inc NUMBER;
v_next_val NUMBER;
pragma autonomous_transaction;
begin
CREATE SEQUENCE sequnce
START WITH YYMMDD0000000001
INCREMENT BY 1
NOCACHE
select sequence.nextval into v_curr_id from dual;
if(substr(v_curr_id,0,6)= to_char(sysdate,'yymmdd')) then
v_next_val := to_number(to_char(SYSDATE+1, 'yymmdd') || '0000000000');
v_inc := v_next_val - v_curr_id;
execute immediate ' alter sequence sequence increment by ' || v_inc ;
select sequence.nextval into v_curr_id from dual;
execute immediate ' alter sequence sequence increment by 1';
else
dbms_output.put_line('exception : file not found');
end if;
RETURN 'ID'||v_curr_id;
END;
这是我如何在一个现有的表和列(名为id)上做到这一点:
UPDATE table SET id=ROWNUM;
DECLARE
maxval NUMBER;
BEGIN
SELECT MAX(id) INTO maxval FROM table;
EXECUTE IMMEDIATE 'DROP SEQUENCE table_seq';
EXECUTE IMMEDIATE 'CREATE SEQUENCE table_seq START WITH '|| TO_CHAR(TO_NUMBER(maxval)+1) ||' INCREMENT BY 1 NOMAXVALUE';
END;
CREATE TRIGGER table_trigger
BEFORE INSERT ON table
FOR EACH ROW
BEGIN
:new.id := table_seq.NEXTVAL;
END;