Linking relational data to folders in XMLDB Repository by using metadata

Question

Hi,
We want to use the XML DB Repository to store documents (PDF, Word, etc) belonging to customers, dossiers of customers, invoices of customers, etc. To accomplish this we are thinking of a folder hierarchy with the first level being customer folders, the second level dossier / invoice folders and within each of these folders the relevant documents / other folders. When querying a customer by sql, we want to determine the correct folder in the repository by storing the primary key of the customer row as user meta data to that folder. After this we get the folders and documents under this folder with the under_path function. Some folders represent a dossier / invoice folder and with this folder the primary key of the dossier / invoice is stored via meta data. While querying these folders by using sql we want to retrieve additional info which is stored in the relational tables: Customer info within a customer table, dossier info within a dossier table, invoice info with an invoice table, etc. Theoretically all available info must be retrieved, so this info preferably must not be stored as metadata (only the primary key and type to these rows and tables).
My question: Is this the right way to go or are we going to face problems with this architecture? Is there a need to store all info as metadata or can it be done as I describe? So we want to link info from different tables to folders / documents in the repository. Because each folder can have metadata pointing to different tables we are facing (even with a small data set) performance issues. Can someone point me in the right direction?
Thanks,
Piotr Chabot Stadhouders
Timeff
The Netherlands

Answer 1

Here's an example, tell me if this is what you need.
Setup : the following creates a table to store a specific type of metadata, two folders, and finally creates a resource (JPEG image) and its associated metadata :
SQL> create table character_metadata (
  2    character_id   number(6)
  3  , character_name varchar2(80)
  4  , origin         varchar2(80)
  5  , category       varchar2(30)
  6  );
Table created.
SQL> declare
  2    res boolean;
  3  begin
  4    res := dbms_xdb.CreateFolder('/ComicBooks');
  5    res := dbms_xdb.CreateFolder('/ComicBooks/Characters');
  6  end;
  7  /
PL/SQL procedure successfully completed.
SQL> commit;
Commit complete.
SQL> declare
  2
  3    v_img_name     varchar2(260) := 'odie.jpg';
  4    v_metadata_id  character_metadata.character_id%type;
  5    res            boolean;
  6
  7  begin
  8
  9    /* Create the resource from the image file*/
10    res := dbms_xdb.CreateResource('/ComicBooks/Characters/' || v_img_name, bfilename('TEST_DIR', v_img_name));
11
12    /* Create the metadata in the dedicated table */
13    insert into character_metadata (character_id, character_name, origin, category)
14    values(1, 'Odie', 'Garfield', 'Dog')
15    returning character_id into v_metadata_id;
16
17    /* Add the pointer in the resource as user-defined metadata (non schema-based) */
18    dbms_xdb.appendResourceMetadata(
19      '/ComicBooks/Characters/' || v_img_name
20    , xmltype( '<cm:CharacterMetadata xmlns:cm="http://mycompany.com/ComicBooks/Characters"><cm:id>' ||
21               to_char(v_metadata_id) ||
22               '</cm:id></cm:CharacterMetadata>' )
23    );
24
25  end;
26  /
PL/SQL procedure successfully completed.
SQL> commit;
Commit complete.A possible query would look like :
SQL> select cm.*
  2       , x.character_pic
  3  from resource_view v
  4     , xmltable(
  5         xmlnamespaces(
  6           'http://mycompany.com/ComicBooks/Characters' as "cm"
  7         , default 'http://xmlns.oracle.com/xdb/XDBResource.xsd'
  8         )
  9       , '/Resource'
10         passing v.res
11         columns metadata_id    number path 'cm:CharacterMetadata/cm:id'
12               , character_pic  blob   path 'XMLLob'
13       ) x
14     , character_metadata cm
15  where under_path(v.res, '/ComicBooks/Characters') = 1
16  and cm.character_id = x.metadata_id
17  ;
CHARACTER_ID CHARACTER_NAME  ORIGIN          CATEGORY        CHARACTER_PIC
           1 Odie            Garfield        Dog             FFD8FFE000104A4649460001010000
                                                             0100010000FFDB0084000906061412
                                                             111414121416141514171717161718
                                                             1815181D17171617151816151A1718
                                                             1C261E1719231918141F2F2223272A
                                                             2C2C2C161EThe image content is retrieved as a BLOB, along with its addtional data.