Oracle SQL Générer un fichier XML imbriqué

Question

Je souhaite obtenir un fichier XML imbriqué en utilisant une seule requête dans une fonction PLSQL pour Oracle.

La base de données (non modifiable):

table 'products_details':

`attr_id` | `attribute` | `fk_parent_id`(Foreign key on `attr_id`) 
------------------------------------------------------------------------------- 
1   | name   | null 
3   | sizes   | null 
4   | size_women  | 3 
5   | size_man  | 3 
6   | size_dimension | 3 

table 'product_contents':

`detail`  | `value` | variation_number | `product_id` (doesnt matter) 
------------------------------------------------------------------------------- 
name   | Tshirt | null    | 1000 
price   | 14.99 | null    | 1000 
size_man  | XL  | 1     | 1000 
size_women | L  | 1     | 1000 
size_dimesion | 21x25cm | 1     | 1000 
size_man  | M  | 2     | 1000 
size_women | S  | 2     | 1000 
size_dimesion | 14x16cm | 2     | 1000 
... 

Comme vous pouvez le voir, il y a quelques options (nom, prix) seulement une fois chaque produit mais il y a aussi quelques options (size_man, size_woman ...) qui sont des variations et peuvent exister plusieurs fois pour chaque produit.

Ce que je veux est un fichier XML:

<attribute detail="name">Tshirt</attribute> 
<attribute detail="price">14.99</attribute> 
<attribute detail="sizes"> 
     <row variation_number="1"> 
      <attribute detail="size_man">XL</attribute> 
      <attribute detail="size_women">L</attribute> 
      ... 
     </row> 
     <row variation_number="2"> 
      <attribute detail="size_man">M</attribute> 
      <attribute detail="size_women">S</attribute> 
     </row> 
</attribute> 

Ce que j'ai essayé jusqu'à présent (ce qui est bien sûr ne fonctionne pas vraiment):

SELECT 
(
    XMLELEMENT( "attribute", 

       XMLATTRIBUTES(pc.detail as "detail"), 

       (SELECT XMLAGG 
       (

       XMLELEMENT("row", XMLATTRIBUTES(pc.variant_number as "variation_number")) 

       ) 

       FROM product_contents pc 

       JOIN product_details pd ON pc.detail = pd.attribute and pc.product_id = '1000' 

       WHERE pd.fk_parent_id = pd.ID 

      )  

).getClobVal() CONTENT 

FROM product_details pd 
pd.fk_parent_id is null 
order by pd.attribute; 

Comment puis-je faire cela avec une seule requête ?

Answer 1

Vous êtes:

WITH 
    -- "memory table" 
    product_details AS (
    SELECT 1 attr_id, 'name' attr, null parent_id FROM dual UNION ALL 
    SELECT 2, 'price', null FROM dual UNION ALL 
    SELECT 3, 'sizes', null FROM dual UNION ALL 
    SELECT 4, 'size_women', 3 FROM dual UNION ALL 
    SELECT 5, 'size_man', 3 FROM dual UNION ALL 
    SELECT 6, 'size_dimension', 3 FROM dual 
), 
    -- "memory table" 
    product_contents AS (
    SELECT 'name' detail, 'Tshirt' value, null variation, 1000 product_id FROM dual UNION ALL 
    SELECT 'price', '14.99', null, 1000 FROM dual UNION ALL 
    SELECT 'size_man', 'XL', 1, 1000 FROM dual UNION ALL 
    SELECT 'size_women', 'L', 1, 1000 FROM dual UNION ALL 
    SELECT 'size_dimesion', '21x25cm', 1, 1000 FROM dual UNION ALL 
    SELECT 'size_man', 'M', 2, 1000 FROM dual UNION ALL 
    SELECT 'size_women', 'S', 2, 1000 FROM dual UNION ALL 
    SELECT 'size_dimesion', '14x16cm', 2, 1000 FROM dual 
), 
    product_contents_xml AS (
    SELECT 
     variation, 
     detail, 
     XMLELEMENT(
     "attribute", 
     XMLATTRIBUTES(detail as "detail"), 
     value 
    ) attr, 
     product_id 
    FROM product_contents 
), 
    attrs AS (
     SELECT 
     pc.attr 
     FROM 
     product_contents_xml pc JOIN 
     product_details pd ON pc.detail = pd.attr and pc.product_id = 1000 
     WHERE 
     pd.parent_id IS NULL 

     UNION ALL 

    SELECT 
     XMLELEMENT("attribute", XMLATTRIBUTES(t.attr AS "detail"), XMLAGG(t.value)) attr 
    FROM ( 
      SELECT 
      parent.attr, 
      XMLELEMENT("row", XMLATTRIBUTES(pc.variation as "variation_number"), XMLAGG(pc.attr)) value 
      FROM 
      product_contents_xml pc JOIN 
      product_details pd ON pc.detail = pd.attr and pc.product_id = 1000 JOIN 
      product_details parent ON parent.attr_id = pd.parent_id 
      WHERE 
      pd.parent_id IS NOT NULL 
      GROUP BY 
      parent.attr, pc.variation 
    ) t 
    GROUP BY t.attr 
) 
SELECT XMLAGG(attr) FROM attrs 

attrs vue est splited en deux parties - l'une pour les attributs sans parent_id et un pour ceux qui ont parent_id.