SCD2 ein Pass merge verletzt Primärschlüssel in Oracle 12

Question

Nach einiger Zeit dachte ich imho recht schnell einen Pass merge Anweisung langsam historisieren Bemaßungstyp Ändern 2.

Es funktioniert perfekt auf Tabellen ohne eindeutige Einschränkung.

Meistens funktioniert es auch auf Tabellen mit eindeutiger Einschränkung. Aber manchmal (normalerweise, wenn die Änderung in der Geschichte größer ist), erhalte ich den Fehler ORA-00001, eine eindeutige Einschränkung der Beschränkung. Natürlich weiß ich, dass es Zwei-Durchlauf-Methoden gibt, die funktionieren, aber sie sind langsamer.

Meine einzige Vermutung ist, dass Oracle manchmal die INSERT vor UPDATE, die den TH_Valid_To_Date für einen Moment dupliziert.

Irgendwelche Ideen, wie man es vermeiden kann (während der Primärschlüssel beibehalten wird)?

Quelltabelle:

CREATE TABLE TESTS 
    (
    T_Key_1      NUMBER(38,0) DEFAULT -1 NOT NULL ENABLE /* */ 
    ,T_Key_2      NUMBER(38,0) DEFAULT -1 NOT NULL ENABLE /* */ 
    ,Text_Value      VARCHAR2(100) /* */ 
    ,Number_Value     NUMBER(38,0) DEFAULT -1 NOT NULL ENABLE /* */ 
    ,Amount       NUMBER   /* */ 

    ,CONSTRAINT T_PK PRIMARY KEY (T_Key_1, T_Key_2) /* Primární klíč */  
) 
; 

Geschichte Tabelle:

CREATE TABLE TEST_HISTORY 
    (
    T_Key_1      NUMBER(38,0) DEFAULT -1 NOT NULL 
    ,T_Key_2      NUMBER(38,0) DEFAULT -1 NOT NULL 
    ,Text_Value      VARCHAR2(100)  
    ,Number_Value     NUMBER(38,0) DEFAULT -1 NOT NULL 
    ,Amount       NUMBER   
    ,TH_Valid_From_Date    DATE   DEFAULT to_date('1000-01-01','yyyy-mm-dd') NOT NULL /* SCD2 - Start of validity of record. */ 
    ,TH_Valid_To_Date    DATE   DEFAULT to_date('3000-01-01','yyyy-mm-dd') NOT NULL /* SCD2 - End of validity of record. */ 

    ,CONSTRAINT TH_PK PRIMARY KEY (T_Key_1, T_Key_2, TH_Valid_To_Date) using index local 
) 
/** Physical Options **************************************************************************************************/ 
partition by range (TH_Valid_To_Date) interval (NUMTOYMINTERVAL (1, 'MONTH')) 
(partition P_10000000 values less than (TO_DATE ('01-01-1000', 'DD-MM-YYYY'))) 
ENABLE ROW MOVEMENT 
; 

Merge:

MERGE INTO (SELECT * FROM TEST_HISTORY WHERE TH_Valid_To_Date = to_date('3000-01-01','yyyy-mm-dd'))    Hst /*change only current records which are identified by TH_Valid_To_Date = to_date('3000-01-01','yyyy-mm-dd') */ 
    USING (
     SELECT * FROM (
     SELECT NVL(Src.T_Key_1, Dst.T_Key_1)        AS T_Key_1 
      ,NVL(Src.T_Key_2, Dst.T_Key_2)         AS T_Key_2 
      ,Src.Text_Value 
      ,Src.Number_Value 
      ,Src.Amount 
      ,CASE WHEN Src.T_Key_1 is null         THEN 'D' /*delete*/ 
        WHEN Dst.T_Key_1 is null         THEN 'I' /*insert*/ 
        WHEN (Src.Text_Value=Dst.Text_Value OR (Src.Text_Value is null AND Dst.Text_Value is null)) 
         AND (Src.Number_Value=Dst.Number_Value OR (Src.Number_Value is null AND Dst.Number_Value is null)) 
         AND (Src.Amount=Dst.Amount OR (Src.Amount is null AND Dst.Amount is null)) 
                      THEN 'X' /*no change*/ 
                      ELSE 'U' /*update*/ END AS Operation 
     FROM TESTS           Src 
     FULL JOIN (SELECT * FROM TEST_HISTORY WHERE TH_Valid_To_Date = to_date('3000-01-01','yyyy-mm-dd'))  Dst 
      ON (Src.T_Key_1 = Dst.T_Key_1 AND Src.T_Key_2 = Dst.T_Key_2) 
    ) 
     INNER JOIN (SELECT LEVEL AS duplication FROM DUAL CONNECT BY LEVEL BETWEEN 1 AND 2) ON (duplication=1 OR Operation='U') /*need to duplicate update records so that they can go to both matched and not matched parts*/ 
     WHERE Operation<>'X' 
    )                   Act 
    ON (Act.T_Key_1 = Hst.T_Key_1 AND Act.T_Key_2 = Hst.T_Key_2 AND Act.duplication=1 AND Act.operation<>'I') 

WHEN MATCHED THEN UPDATE 
    SET 
     TH_Valid_To_Date        = p_Load_Date - 1, 
    WHERE Hst.TH_Valid_To_Date      = to_date('3000-01-01','yyyy-mm-dd') 

WHEN NOT MATCHED THEN INSERT /*+ append */ 
    (
     T_Key_1      
     ,T_Key_2      
     ,Text_Value      
     ,Number_Value     
     ,Amount       
     ,TH_Valid_From_Date    /*Auditní sloupec*/ 
     ,TH_Valid_To_Date    /*Auditní sloupec*/ 
    ) VALUES (
     Act.T_Key_1      
     ,Act.T_Key_2      
     ,Act.Text_Value      
     ,Act.Number_Value     
     ,Act.Amount       
     ,p_Load_Date     /*Auditní sloupec*/ 
     ,to_date('3000-01-01','yyyy-mm-dd') /*Auditní sloupec*/ 
    ) 
; 

Answer 1

Ich lief in das gleiche Problem selbst: Sie können beide nicht einfügen und einen Datensatz aktualisieren. Oracle bestimmt, ob der Datensatz eingefügt oder aktualisiert werden soll, wenn der Join zum ersten Mal ausgeführt wird. Hier ist ein vereinfachter Testfall, der dies veranschaulicht:

-- This is the table into which we will be merging data 

CREATE TABLE merge_table 
(
    mt_col1 INTEGER NOT NULL 
    , mt_col2 INTEGER 
); 

-- Make mt_col1 unique 
ALTER TABLE merge_table ADD (
    UNIQUE (mt_col1) 
    USING INDEX); 

-- This is the table from which we will be drawing the data 

CREATE TABLE datasource_table 
(
    ds_col1 INTEGER 
    , ds_col2 INTEGER 
); 

-- Load up the data source with 10 rows (1-10) 

INSERT INTO datasource_table (
      ds_col1, ds_col2 
      ) 
    SELECT ROWNUM r, ROWNUM r 
     FROM all_objects 
    WHERE ROWNUM < 11; 

-- Create a duplicate record 

INSERT INTO datasource_table (
      ds_col1, ds_col2 
      ) 
    VALUES (1, 1); 

-- Create a record to be updated 

INSERT INTO merge_table (
      mt_col1, mt_col2 
      ) 
    VALUES (2, 2); 

COMMIT; 

-- This merge will fail with a unique constraint violation because 
-- an mt_col1 value of 1 does not exist. The datasource table contains 
-- two entries for 1, so the merge will try to insert two mt_col1=1 records, 
-- violating the unique constraint. 

MERGE INTO merge_table dt 
    USING (SELECT ds_col1, ds_col2 
       FROM datasource_table) a 
     ON (a.ds_col1 = dt.mt_col1) 
WHEN MATCHED 
THEN 
    UPDATE SET mt_col2 = a.ds_col2 + 10 
WHEN NOT MATCHED 
THEN 
    INSERT  (
       mt_col1, mt_col2 
       ) 
     VALUES (ds_col1, ds_col2); 

-- ORA-00001: unique constraint (SYS_C0013990) violated 

-- Delete one of the duplicate records and the merge succeeds 

DELETE FROM datasource_table 
     WHERE ds_col1 = 1 
     AND ROWNUM < 2; 

-- Merge is now successful 

MERGE INTO merge_table dt 
    USING (SELECT ds_col1, ds_col2 
       FROM datasource_table) a 
     ON (a.ds_col1 = dt.mt_col1) 
WHEN MATCHED 
THEN 
    UPDATE SET mt_col2 = a.ds_col2 + 10 
WHEN NOT MATCHED 
THEN 
    INSERT  (
       mt_col1, mt_col2 
       ) 
     VALUES (ds_col1, ds_col2); 

-- 10 rows updated