Wie Zugriff auf Varray-Element in SQL in der Tabellenspalte

Question

Ich versuche, eine easy Weg zum Zugriff auf Varray-Element in der Tabellenspalte in einer SQL-Abfrage zu finden. Spalten-ID des Varray-Typs, muss jedoch einem Datenbank-Client mit jedem Element als Spalte angezeigt werden. So etwas wie column_name (1) .x, column_name (1) .y, .. column_name (20) .y Wir verwenden derzeit eine Funktion Array-Elemente als Spalte

create or replace function get_point_x(
    p_graph in graph_t, 
    p_point in PLS_INTEGER 
) 
return number 
is 
begin 
    return p_graph(p_point).x; 
exception 
when no_data_found then 
    return to_number(null); 
end get_point_x; 
/

jedoch dem Aufruf dieser Funktion 40mal zurückzukehren Pro Zeile dauert etwa 40% der Abfrage verstrichene Zeit. Also frage ich mich, ob es eine einfache und effiziente SQL-Alternative gibt, um auf ein Element in SQL-Abfrage zuzugreifen. Ich habe den folgenden Ansatz versucht, aber es ist nicht viel effizienter als die PLSQL-Funktion !?

-- A graph point 
CREATE TYPE point_t AS object(
x number(6,0), 
y number(6,0) 
); 
/

-- Graph can contain up to 20 points, no more 
CREATE TYPE graph_t AS VARRAY(20) OF point_t; 
/

-- Customer graphs 
create table customer_graphs (customer_id number(9,0), graph graph_t); 

insert into customer_graphs values(1, graph_t(point_t(10,10), point_t(20,20), point_t(30,30))); 

insert into customer_graphs values(2, graph_t(point_t(5,5), point_t(10,10), point_t(30,30), point_t(40,31))); 

-- That works but returns graph points as rows 
-- But I need columns x1, y1, ..x20, y20 
select cg.customer_id, g.* from customer_graphs cg, TABLE(cg.graph) g; 

-- Of cource I can pivot but it impacts performance with 40 columns 
select 
    customer_id, 
    max(
    CASE rn 
     WHEN 1 
     THEN x 
    END 
) x_1, 
    max(
    CASE rn 
     WHEN 1 
     THEN y 
    END 
) y_1, 
    max(
    CASE rn 
     WHEN 2 
     THEN x 
    END 
) x_2, 
    max(
    CASE rn 
     WHEN 2 
     THEN y 
    END 
) y_2, 
    -- .. 
    max(
    CASE rn 
     WHEN 20 
     THEN x 
    END 
) x_20, 
    max(
    CASE rn 
     WHEN 20 
     THEN y 
    END 
) y_20 
from (
    select cg.customer_id, g.*, row_number() over(partition by cg.customer_id order by g.x) rn 
    from 
    customer_graphs cg, 
    TABLE(cg.graph) g 
) 
group by customer_id 
; 

-- Is there an easy way to access volumn's varray element in SQL?? 
-- Something like below 
select 
    cg.customer_id, 
    cg.graph, 
-- From this line on it does not work 
cg.graph(1).x x_1, 
cg.graph(1).y y_1, 
-- .. 
cg.graph(20).x x_20, 
cg.graph(20).y y_20 
from customer_graphs cg; 

ORA-00904: "CG"."GRAPH": invalid identifier 
00904. 00000 - "%s: invalid identifier" 
*Cause:  
*Action: 
Error at Line: 258 Column: 2 

Gibt es eine effiziente SQL Lösung gibt, die ich fehle?

Vielen Dank im Voraus

Answer 1

Die beste Lösung alles in einfachen Tabellen löschen Typen und VARRAYs und speichern wäre.

Wenn dies keine Option ist, können Sie die Leistung erheblich verbessern, indem Sie den VARRAY in einen Objekttyp einschließen und Elemente über Elementfunktionen zugreifen. Dieser Ansatz ist um ein Vielfaches schneller als das Verschwenken eines VARRAY.

Der folgende Code ist ein bisschen schmerzhaft, aber es ist ein voll funktionsfähiger Test von 20 Spalten mit 100.000 Probenzeilen.

Beispielschema mit VARRAY

CREATE TYPE point_t AS object(
x number(6,0), 
y number(6,0) 
); 

-- Graph can contain up to 20 points, no more 
CREATE TYPE graph_t AS VARRAY(20) OF point_t; 

-- Customer graphs 
create table customer_graphs (customer_id number(9,0), graph graph_t); 

--100K rows, 5.2 seconds. 
begin 
    for i in 1 .. 100000 loop 
     insert into customer_graphs values(i, graph_t(point_t(1,1),point_t(2,2),point_t(3,3),point_t(4,4),point_t(5,5),point_t(6,6),point_t(7,7),point_t(8,8),point_t(9,9),point_t(10,10),point_t(11,11),point_t(12,12),point_t(13,13),point_t(14,14),point_t(15,15),point_t(16,16),point_t(17,17),point_t(18,18),point_t(19,19),point_t(20,20))); 
    end loop; 
    commit; 
end; 
/

begin 
    dbms_stats.gather_table_stats(user, 'CUSTOMER_GRAPHS'); 
end; 
/

Beispielschema mit Objekt mit VARRAY

--Create type to store and access graph and X and Y elements. 
create or replace type graph_obj as object 
(
    graph graph_t, 
    member function x(p_index number) return number, 
    member function y(p_index number) return number 
); 

create or replace type body graph_obj is 
    member function x(p_index number) return number is 
    begin 
     return graph(p_index).x; 
    end; 

    member function y(p_index number) return number is 
    begin 
     return graph(p_index).y; 
    end; 
end; 
/

-- Customer graphs 2 
create table customer_graphs2(customer_id number(9,0), graph graph_obj); 

--100K rows, 5.54 seconds. 
begin 
    for i in 1 .. 100000 loop 
     insert into customer_graphs2 values(i, graph_obj(graph_t(point_t(1,1),point_t(2,2),point_t(3,3),point_t(4,4),point_t(5,5),point_t(6,6),point_t(7,7),point_t(8,8),point_t(9,9),point_t(10,10),point_t(11,11),point_t(12,12),point_t(13,13),point_t(14,14),point_t(15,15),point_t(16,16),point_t(17,17),point_t(18,18),point_t(19,19),point_t(20,20)))); 
    end loop; 
    commit; 
end; 
/

begin 
    dbms_stats.gather_table_stats(user, 'CUSTOMER_GRAPHS2'); 
end; 
/

VARRAY PIVOT Leistung

Erste N Zeilen - 4,5 Sekunden.

select customer_id, 
    max(CASE rn WHEN 1 THEN x END) x_1, max(CASE rn WHEN 1 THEN y END) y_1, max(CASE rn WHEN 2 THEN x END) x_2, max(CASE rn WHEN 2 THEN y END) y_2, max(CASE rn WHEN 3 THEN x END) x_3, max(CASE rn WHEN 3 THEN y END) y_3, max(CASE rn WHEN 4 THEN x END) x_4, max(CASE rn WHEN 4 THEN y END) y_4, max(CASE rn WHEN 5 THEN x END) x_5, max(CASE rn WHEN 5 THEN y END) y_5, max(CASE rn WHEN 6 THEN x END) x_6, max(CASE rn WHEN 6 THEN y END) y_6, max(CASE rn WHEN 7 THEN x END) x_7, max(CASE rn WHEN 7 THEN y END) y_7, max(CASE rn WHEN 8 THEN x END) x_8, max(CASE rn WHEN 8 THEN y END) y_8, max(CASE rn WHEN 9 THEN x END) x_9, max(CASE rn WHEN 9 THEN y END) y_9, max(CASE rn WHEN 10 THEN x END) x_10, max(CASE rn WHEN 10 THEN y END) y_10, max(CASE rn WHEN 11 THEN x END) x_11, max(CASE rn WHEN 11 THEN y END) y_11, max(CASE rn WHEN 12 THEN x END) x_12, max(CASE rn WHEN 12 THEN y END) y_12, max(CASE rn WHEN 13 THEN x END) x_13, max(CASE rn WHEN 13 THEN y END) y_13, max(CASE rn WHEN 14 THEN x END) x_14, max(CASE rn WHEN 14 THEN y END) y_14, max(CASE rn WHEN 15 THEN x END) x_15, max(CASE rn WHEN 15 THEN y END) y_15, max(CASE rn WHEN 16 THEN x END) x_16, max(CASE rn WHEN 16 THEN y END) y_16, max(CASE rn WHEN 17 THEN x END) x_17, max(CASE rn WHEN 17 THEN y END) y_17, max(CASE rn WHEN 18 THEN x END) x_18, max(CASE rn WHEN 18 THEN y END) y_18, max(CASE rn WHEN 19 THEN x END) x_19, max(CASE rn WHEN 19 THEN y END) y_19, max(CASE rn WHEN 20 THEN x END) x_20, max(CASE rn WHEN 20 THEN y END) y_20 
from (
    select cg.customer_id, g.*, row_number() over(partition by cg.customer_id order by g.x) rn 
    from 
    customer_graphs cg, 
    TABLE(cg.graph) g 
) 
group by customer_id; 

Alle Zeilen - 17 Sekunden

select sum(x_1) x 
from 
(
    select customer_id, 
     max(CASE rn WHEN 1 THEN x END) x_1, max(CASE rn WHEN 1 THEN y END) y_1, max(CASE rn WHEN 2 THEN x END) x_2, max(CASE rn WHEN 2 THEN y END) y_2, max(CASE rn WHEN 3 THEN x END) x_3, max(CASE rn WHEN 3 THEN y END) y_3, max(CASE rn WHEN 4 THEN x END) x_4, max(CASE rn WHEN 4 THEN y END) y_4, max(CASE rn WHEN 5 THEN x END) x_5, max(CASE rn WHEN 5 THEN y END) y_5, max(CASE rn WHEN 6 THEN x END) x_6, max(CASE rn WHEN 6 THEN y END) y_6, max(CASE rn WHEN 7 THEN x END) x_7, max(CASE rn WHEN 7 THEN y END) y_7, max(CASE rn WHEN 8 THEN x END) x_8, max(CASE rn WHEN 8 THEN y END) y_8, max(CASE rn WHEN 9 THEN x END) x_9, max(CASE rn WHEN 9 THEN y END) y_9, max(CASE rn WHEN 10 THEN x END) x_10, max(CASE rn WHEN 10 THEN y END) y_10, max(CASE rn WHEN 11 THEN x END) x_11, max(CASE rn WHEN 11 THEN y END) y_11, max(CASE rn WHEN 12 THEN x END) x_12, max(CASE rn WHEN 12 THEN y END) y_12, max(CASE rn WHEN 13 THEN x END) x_13, max(CASE rn WHEN 13 THEN y END) y_13, max(CASE rn WHEN 14 THEN x END) x_14, max(CASE rn WHEN 14 THEN y END) y_14, max(CASE rn WHEN 15 THEN x END) x_15, max(CASE rn WHEN 15 THEN y END) y_15, max(CASE rn WHEN 16 THEN x END) x_16, max(CASE rn WHEN 16 THEN y END) y_16, max(CASE rn WHEN 17 THEN x END) x_17, max(CASE rn WHEN 17 THEN y END) y_17, max(CASE rn WHEN 18 THEN x END) x_18, max(CASE rn WHEN 18 THEN y END) y_18, max(CASE rn WHEN 19 THEN x END) x_19, max(CASE rn WHEN 19 THEN y END) y_19, max(CASE rn WHEN 20 THEN x END) x_20, max(CASE rn WHEN 20 THEN y END) y_20 
    from (
     select cg.customer_id, g.*, row_number() over(partition by cg.customer_id order by g.x) rn 
     from 
     customer_graphs cg, 
     TABLE(cg.graph) g 
    ) 
    group by customer_id 
); 

objekt

ersten N Zeilen - 0,4 Sekunden

select cg.customer_id, cg.graph.x(1) x_1, cg.graph.y(1) y_1, cg.graph.x(2) x_2, cg.graph.y(2) y_2, cg.graph.x(3) x_3, cg.graph.y(3) y_3, cg.graph.x(4) x_4, cg.graph.y(4) y_4, cg.graph.x(5) x_5, cg.graph.y(5) y_5, cg.graph.x(6) x_6, cg.graph.y(6) y_6, cg.graph.x(7) x_7, cg.graph.y(7) y_7, cg.graph.x(8) x_8, cg.graph.y(8) y_8, cg.graph.x(9) x_9, cg.graph.y(9) y_9, cg.graph.x(10) x_10, cg.graph.y(10) y_10, cg.graph.x(11) x_11, cg.graph.y(11) y_11, cg.graph.x(12) x_12, cg.graph.y(12) y_12, cg.graph.x(13) x_13, cg.graph.y(13) y_13, cg.graph.x(14) x_14, cg.graph.y(14) y_14, cg.graph.x(15) x_15, cg.graph.y(15) y_15, cg.graph.x(16) x_16, cg.graph.y(16) y_16, cg.graph.x(17) x_17, cg.graph.y(17) y_17, cg.graph.x(18) x_18, cg.graph.y(18) y_18, cg.graph.x(19) x_19, cg.graph.y(19) y_19, cg.graph.x(20) x_20, cg.graph.y(20) y_20 
from customer_graphs2 cg; 

Alle Zeilen - 2.5 Sekunden

select sum(x_1) 
from 
(
    select cg.customer_id, cg.graph.x(1) x_1, cg.graph.y(1) y_1, cg.graph.x(2) x_2, cg.graph.y(2) y_2, cg.graph.x(3) x_3, cg.graph.y(3) y_3, cg.graph.x(4) x_4, cg.graph.y(4) y_4, cg.graph.x(5) x_5, cg.graph.y(5) y_5, cg.graph.x(6) x_6, cg.graph.y(6) y_6, cg.graph.x(7) x_7, cg.graph.y(7) y_7, cg.graph.x(8) x_8, cg.graph.y(8) y_8, cg.graph.x(9) x_9, cg.graph.y(9) y_9, cg.graph.x(10) x_10, cg.graph.y(10) y_10, cg.graph.x(11) x_11, cg.graph.y(11) y_11, cg.graph.x(12) x_12, cg.graph.y(12) y_12, cg.graph.x(13) x_13, cg.graph.y(13) y_13, cg.graph.x(14) x_14, cg.graph.y(14) y_14, cg.graph.x(15) x_15, cg.graph.y(15) y_15, cg.graph.x(16) x_16, cg.graph.y(16) y_16, cg.graph.x(17) x_17, cg.graph.y(17) y_17, cg.graph.x(18) x_18, cg.graph.y(18) y_18, cg.graph.x(19) x_19, cg.graph.y(19) y_19, cg.graph.x(20) x_20, cg.graph.y(20) y_20 
    from customer_graphs2 cg 
); 

Answer 2

Setup-

CREATE TYPE point_t AS object(
x number(6,0), 
y number(6,0) 
); 
/
-- Graph can contain up to 20 points, no more 
CREATE TYPE graph_t AS VARRAY(20) OF point_t; 
/
-- Customer graphs 
create table customer_graphs (customer_id number(9,0), graph graph_t); 

BEGIN 

    FOR i IN 1 .. 100000 
    LOOP 
    -- build graph as it may contain up to 20 points 

    DECLARE 
     lv_graph graph_t := graph_t(); 
    BEGIN 

     FOR j IN 1..mod(i, 20) + 1 
     LOOP 

     lv_graph.extend(); 
     lv_graph(j) := point_t(i, i); 

     END LOOP; 

     INSERT INTO customer_graphs VALUES (i, lv_graph); 

    END; 

    END LOOP; 

    COMMIT; 

END; 
/

begin 
    dbms_stats.gather_table_stats(user, 'CUSTOMER_GRAPHS'); 
end; 
/

Original-PL/SQL-Funktionen

create or replace function x(p_graph graph_t, p_index number) return number is 
    begin 
     if p_graph.exists(p_index) then 
      return p_graph(p_index).x; 
     else 
      return to_number(null); 
     end if; 
    end; 
/ 

create or replace function y(p_graph graph_t, p_index number) return number is 
    begin 
     if p_graph.exists(p_index) then 
     return p_graph(p_index).y; 
     else 
      return to_number(null); 
     end if; 
    end; 
/

Jon Heller Beratung (leicht modifiziert)

I-Test für NULL-Werte hinzugefügt, da Graph nicht enthalten immer alle 20 Punkte.

create or replace type graph_obj as object 
(
    graph graph_t, 
    member function x(p_index number) return number, 
    member function y(p_index number) return number 
); 
/

create or replace type body graph_obj is 
    member function x(p_index number) return number is 
    begin 
     if graph.exists(p_index) then 
      return graph(p_index).x; 
     else 
      return to_number(null); 
     end if; 
    end; 

    member function y(p_index number) return number is 
    begin 
     if graph.exists(p_index) then 
     return graph(p_index).y; 
     else 
      return to_number(null); 
     end if; 
    end; 
end; 
/

Diese Anwendung ist sehr alt und wird von so vielen anderen Anwendungen verwendet. Ich schreibe eine Schnittstelle für eine weitere App. Ich kann sehen, wie sich diese Anwendung im Laufe der Zeit entwickelt hat: Zuerst wurden relationale Tabellen verwendet, dann VARRAYs und dann verschachtelte Tabellen (ich gehe davon aus, dass das objektorientierte Paradigma schick und trendy war)), und jetzt gute alte relationale Tabellen. Ich stimme zu, dass es besser ist, einfache relationale Tabellen zu verwenden.

Ich kann die Anwendung nicht ändern. So erstellte ich graph_obj Objekte im laufenden Betrieb. Ich brauche alle Zeilen. Ich lief Abfragen in SQL * Plus mit

set timing on 
set arraysize 5000 
set autotrace TRACEONLY statistics 

Ich habe nicht sum (x_1) Trick verwenden, da Oracle smart nicht anderen 39 Anrufe ausführen berechnen y_1, .., x_20, y_20. Deshalb schien der Objektansatz schneller zu sein als der Drehpunkt.

VARRAY Pivot Leistung

-- Pivot 13 secs 
select customer_id, 
     max(CASE rn WHEN 1 THEN x END) x_1, max(CASE rn WHEN 1 THEN y END) y_1, max(CASE rn WHEN 2 THEN x END) x_2, max(CASE rn WHEN 2 THEN y END) y_2, max(CASE rn WHEN 3 THEN x END) x_3, max(CASE rn WHEN 3 THEN y END) y_3, max(CASE rn WHEN 4 THEN x END) x_4, max(CASE rn WHEN 4 THEN y END) y_4, max(CASE rn WHEN 5 THEN x END) x_5, max(CASE rn WHEN 5 THEN y END) y_5, max(CASE rn WHEN 6 THEN x END) x_6, max(CASE rn WHEN 6 THEN y END) y_6, max(CASE rn WHEN 7 THEN x END) x_7, max(CASE rn WHEN 7 THEN y END) y_7, max(CASE rn WHEN 8 THEN x END) x_8, max(CASE rn WHEN 8 THEN y END) y_8, max(CASE rn WHEN 9 THEN x END) x_9, max(CASE rn WHEN 9 THEN y END) y_9, max(CASE rn WHEN 10 THEN x END) x_10, max(CASE rn WHEN 10 THEN y END) y_10, max(CASE rn WHEN 11 THEN x END) x_11, max(CASE rn WHEN 11 THEN y END) y_11, max(CASE rn WHEN 12 THEN x END) x_12, max(CASE rn WHEN 12 THEN y END) y_12, max(CASE rn WHEN 13 THEN x END) x_13, max(CASE rn WHEN 13 THEN y END) y_13, max(CASE rn WHEN 14 THEN x END) x_14, max(CASE rn WHEN 14 THEN y END) y_14, max(CASE rn WHEN 15 THEN x END) x_15, max(CASE rn WHEN 15 THEN y END) y_15, max(CASE rn WHEN 16 THEN x END) x_16, max(CASE rn WHEN 16 THEN y END) y_16, max(CASE rn WHEN 17 THEN x END) x_17, max(CASE rn WHEN 17 THEN y END) y_17, max(CASE rn WHEN 18 THEN x END) x_18, max(CASE rn WHEN 18 THEN y END) y_18, max(CASE rn WHEN 19 THEN x END) x_19, max(CASE rn WHEN 19 THEN y END) y_19, max(CASE rn WHEN 20 THEN x END) x_20, max(CASE rn WHEN 20 THEN y END) y_20 
    from (
     select cg.customer_id, g.*, row_number() over(partition by cg.customer_id order by g.x) rn 
     from 
     customer_graphs cg, 
     TABLE(cg.graph) g 
    ) 
    group by customer_id; 

Original-PLSQL Funktionen Leistungsfähigkeit

-- PLSQL 75 secs. 
select cg.customer_id, x(cg.graph,1) x_1, y(cg.graph,1) y_1, x(cg.graph,2) x_2, y(cg.graph,2) y_2, x(cg.graph,3) x_3, y(cg.graph,3) y_3, x(cg.graph,4) x_4, y(cg.graph,4) y_4, x(cg.graph,5) x_5, y(cg.graph,5) y_5, x(cg.graph,6) x_6, y(cg.graph,6) y_6, x(cg.graph,7) x_7, y(cg.graph,7) y_7, x(cg.graph,8) x_8, y(cg.graph,8) y_8, x(cg.graph,9) x_9, y(cg.graph,9) y_9, x(cg.graph,10) x_10, y(cg.graph,10) y_10, x(cg.graph,11) x_11, y(cg.graph,11) y_11, x(cg.graph,12) x_12, y(cg.graph,12) y_12, x(cg.graph,13) x_13, y(cg.graph,13) y_13, x(cg.graph,14) x_14, y(cg.graph,14) y_14, x(cg.graph,15) x_15, y(cg.graph,15) y_15, x(cg.graph,16) x_16, y(cg.graph,16) y_16, x(cg.graph,17) x_17, y(cg.graph,17) y_17, x(cg.graph,18) x_18, y(cg.graph,18) y_18, x(cg.graph,19) x_19, y(cg.graph,19) y_19, x(cg.graph,20) x_20, y(cg.graph,20) y_20 
    from customer_graphs cg; 

Objekt Leistung

-- Object 83 secs, 6 times slower than pivot query 
-- I assume that additional 8 secs were caused by creating objects on the fly 

    select cg.customer_id, cg.graph.x(1) x_1, cg.graph.y(1) y_1, cg.graph.x(2) x_2, cg.graph.y(2) y_2, cg.graph.x(3) x_3, cg.graph.y(3) y_3, cg.graph.x(4) x_4, cg.graph.y(4) y_4, cg.graph.x(5) x_5, cg.graph.y(5) y_5, cg.graph.x(6) x_6, cg.graph.y(6) y_6, cg.graph.x(7) x_7, cg.graph.y(7) y_7, cg.graph.x(8) x_8, cg.graph.y(8) y_8, cg.graph.x(9) x_9, cg.graph.y(9) y_9, cg.graph.x(10) x_10, cg.graph.y(10) y_10, cg.graph.x(11) x_11, cg.graph.y(11) y_11, cg.graph.x(12) x_12, cg.graph.y(12) y_12, cg.graph.x(13) x_13, cg.graph.y(13) y_13, cg.graph.x(14) x_14, cg.graph.y(14) y_14, cg.graph.x(15) x_15, cg.graph.y(15) y_15, cg.graph.x(16) x_16, cg.graph.y(16) y_16, cg.graph.x(17) x_17, cg.graph.y(17) y_17, cg.graph.x(18) x_18, cg.graph.y(18) y_18, cg.graph.x(19) x_19, cg.graph.y(19) y_19, cg.graph.x(20) x_20, cg.graph.y(20) y_20 
    from (
    select cgi.customer_id, graph_obj(cgi.graph) graph 
    from customer_graphs cgi 
    ) cg 
;