Oracle 如何在更短的时间内有效地更新每个表中有5L记录的循环表

CURSOR C_TABLES IS
      SELECT TABLE_NAME
        FROM ALL_TABLES
       WHERE TABLE_NAME LIKE '%Condtion%';

FOR REC_TAB IN C_TABLES LOOP
    
      V_SQL_STRING := 'SELECT TABLE_NAME.C1,
                       TABLE_NAME.C2,
                TABLE_NAME.C3,
                NVL(IRS.C4,''UNDEFINED'') SM
           FROM ' || REC_TAB.TABLE_NAME ||
                      ' TABLE_NAME, T2 IRS
          WHERE TABLE_NAME.C1= T2.C1
            AND TABLE_NAME.C2 BETWEEN IRS.C2 AND IRS.C3';
    
      OPEN Cursor FOR V_SQL_STRING;
    
      LOOP
        FETCH V_Cursor
          INTO V_C1, V_C2, V_C3, V_C4;
        EXIT WHEN V_Cursor%NOTFOUND;
      
        V_SQL_STRING := ' UPDATE ' || REC_TAB.TABLE_NAME ||
                        ' SET C3= ''' || V_C4|| '''
           WHERE C1= ''' || V_C1|| '''
           AND C2= ''' || V_C2|| '''
           AND C3= ''' || C_C3|| ''' ';
      
        EXECUTE IMMEDIATE V_SQL_STRING;
        ---DBMS_OUTPUT.PUT_LINE('Updated Table:' || REC_TAB.TABLE_NAME);
        COMMIT;
      END LOOP;    
END LOOP;
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V_SQL_STRING := ' UPDATE ' || REC_TAB.TABLE_NAME ||
                        ' SET C3= ''' || V_C4|| '''
           WHERE C1= ''' || V_C1|| '''
           AND C2= ''' || V_C2|| '''
           AND C3= ''' || C_C3|| ''' ';
      
        EXECUTE IMMEDIATE V_SQL_STRING;
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V_SQL_STRING := ' UPDATE ' || REC_TAB.TABLE_NAME ||
                        ' SET C3= :1 '||
           ' WHERE C1= :2'||
           ' AND C2= :3 '||
           ' AND C3= :4 ';
      
        EXECUTE IMMEDIATE V_SQL_STRING using v_c1, v_c2, v_c3, v_c4;
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COMMIT;
      END LOOP;    
END LOOP;
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  END LOOP;    
  COMMIT;
END LOOP;
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