postgresql中的動態upsert

Question

我有這個upsert函數，允許我修改一行的fill_rate列。

CREATE FUNCTION upsert_fillrate_alarming(integer, boolean) RETURNS VOID AS ' 
DECLARE 
    num ALIAS FOR $1; 
    dat ALIAS FOR $2; 

BEGIN 
    LOOP 
     -- First try to update. 
    UPDATE alarming SET fill_rate = dat WHERE equipid = num; 
    IF FOUND THEN 
     RETURN; 
    END IF; 
    -- Since its not there we try to insert the key 
    -- Notice if we had a concurent key insertion we would error 
    BEGIN 
     INSERT INTO alarming (equipid, fill_rate) VALUES (num, dat); 
     RETURN; 
    EXCEPTION WHEN unique_violation THEN 
     -- Loop and try the update again 
    END; 
    END LOOP; 
END; 
' LANGUAGE 'plpgsql'; 

是否有可能修改此函數以獲取列參數？如果有辦法修改函數以獲取列和表格，則需要額外的獎勵分數。

Answer 1

您想要了解關於dynamic commands in plsql的更多信息。 只需構建您的查詢並調用EXECUTE。

Answer 2

也許更簡單的方法，只是少線;）

CREATE OR REPLACE FUNCTION upsert_tableName(arg1 type, arg2 type) RETURNS VOID AS $$ 
DECLARE 
BEGIN 
    UPDATE tableName SET col1 = value WHERE colX = arg1 and colY = arg2; 
    IF NOT FOUND THEN 
    INSERT INTO tableName values (value, arg1, arg2); 
    END IF; 
END; 
$$ LANGUAGE 'plpgsql'; 

Answer 3

作爲一種替代方法，您可以通過使用插入+更新WHERE子句，使他們只許成功做一個UPSERT 沒有功能在正確的情況下。例如。

update mytable set col1='value1' where (col2 = 'myId'); 
insert into mytable select 'value1', 'myId' where not exists (select 1 from mytable where col2='myId'); 

這將避免有大量的自定義postgres特定功能。