在DB2

Question

創建從一個共享序列主鍵我想在DB2（10.5 LUW）使用單個序列的所有主鍵。

但是我瞎了雙眼沒有設法找到一個方法來做到這一點..最近我可以是使用功能，但是當多個值插入到相同的語句失敗。這是因爲該功能只被評估一次。可以通過添加列值的依賴來調整，但不喜歡這樣做。

The question relates to my previous one

CREATE SEQUENCE TEST.ID_SEQ AS BIGINT START WITH 10000 INCREMENT BY 1 NO MAXVALUE NO CYCLE CACHE 100 
GO 
--- Bad "hack" since the function is not deterministic 
--- see comments below 
CREATE OR REPLACE FUNCTION TEST.OBJECT_ID() 
    RETURNS BIGINT SPECIFIC TEST.OBJECT_ID 
    CONTAINS SQL DETERMINISTIC NO EXTERNAL ACTION 
    BEGIN 
    DECLARE B BIGINT; 
    SET B = NEXT VALUE FOR TEST.ID_SEQ ; 
    RETURN B ; 
    END 
GO 

CREATE TABLE TEST.TEST (
    ID BIGINT  NOT NULL PRIMARY KEY GENERATED ALWAYS AS (TEST.OBJECT_ID()), 
    TEST VARCHAR(10) 
) 
GO 

Answer 1

您可以使用自動增量

create table TEST.TEST (
id integer not null GENERATED ALWAYS AS IDENTITY (START WITH 10000 INCREMENT BY 1) 
,TEST varchar(30) 
,PRIMARY KEY (id) 
); 

或使用插入這樣

INSERT INTO ORDERS (ORDERNO, CUSTNO) VALUES (NEXT VALUE FOR ORDER_SEQ, 12) 

Answer 2

的腳本，給什麼就足夠了榜樣有一個表作爲一個用於多個TABLE的父項[顯示兩個子表，每個都有相同 INSERT TRIGGER]，橫跨每個將具有從剛好一個分配的下一序列值，從而共享 SEQUENCE。當然，家長將得到每一個序列值，和每個孩子將得到只有那些沒有在任何其他子表值：

drop table AppFile01 ; 
drop table AppFile02 ; 
drop table Master_IDENTITY ; 
drop sequence  ID_SEQ ;  

create table Master_IDENTITY 
(Master_ID BIGINT NOT NULL 
, constraint Master_IDENTITY_PK 
    PRIMARY KEY (Master_ID) 
) 
; 
CREATE SEQUENCE  ID_SEQ AS BIGINT 
    START WITH 10000 INCREMENT BY 1  
    NO MAXVALUE NO CYCLE CACHE 100  
; 
create table AppFile01 
(sKeyAF  BIGINT  not null  
, ts   timestamp default current timestamp 
, constraint AppFile01_PK  
    PRIMARY KEY (sKeyAF)  
, constraint AppFile01_FK  
    FOREIGN KEY (sKeyAF)  
    REFERENCES Master_IDENTITY (Master_ID) 
    ON DELETE CASCADE ON UPDATE NO ACTION 
) 
; 
create trigger AppFile01_BI BEFORE INSERT 
on AppFile01  
referencing new as N 
for each row mode db2sql  
begin  
declare NxtSeq BIGINT ; 
set NxtSeq = NEXT VALUE FOR ID_SEQ ; 
insert into Master_IDENTITY values (NxtSeq) ; 
set N.sKeyAF = NxtSeq ; 
end  
; 
create table AppFile02 
(sKeyAF  BIGINT  not null  
, ts   timestamp default current timestamp 
, constraint AppFile02_PK  
    PRIMARY KEY (sKeyAF)  
, constraint AppFile02_FK  
    FOREIGN KEY (sKeyAF)  
    REFERENCES Master_IDENTITY (Master_ID) 
    ON DELETE CASCADE ON UPDATE NO ACTION 
) 
; 
create trigger AppFile02_BI BEFORE INSERT 
on AppFile02  
referencing new as N 
for each row mode db2sql 
begin  
declare NxtSeq BIGINT ; 
set NxtSeq = NEXT VALUE FOR ID_SEQ ; 
insert into Master_IDENTITY values (NxtSeq) ; 
set N.sKeyAF = NxtSeq ; 
end  
; 

而下面的請求，測試和顯示效果;沒有特別的原因，我選擇使用的文字值-1過，例如，DEFAULT：

insert into AppFile01 values(-1, DEFAULT) ; 
; -- gets value 10000  
insert into AppFile02 values(-1, DEFAULT) 
     , (-1, DEFAULT) 
; -- gets values 10001 and 10002 
insert into AppFile01 values(-1, DEFAULT) ; 
; -- gets value 10003  
select * from master_id 
; -- likeness of report from above query 
      MASTER_ID 
      10,000 
      10,001 
      10,002 
      10,003 
select * from appfile01 
; -- likeness of report from above query 
      SKEYAF TS       
      10,000 2016-10-09-18.38.28.347468 
      10,003 2016-10-09-18.38.28.400702 
select * from appfile02 
; -- likeness of report from above query 
      SKEYAF TS       
      10,001 2016-10-09-18.38.28.372121 
      10,002 2016-10-09-18.38.28.386622