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From b..@apache.org
Subject cvs commit: db-ojb/xdocs query.xml
Date Sun, 16 Feb 2003 13:24:32 GMT
brj         2003/02/16 05:24:32

  Modified:    xdocs    query.xml
  Log:
  sample for extent aware path expression
  
  Revision  Changes    Path
  1.13      +30 -1     db-ojb/xdocs/query.xml
  
  Index: query.xml
  ===================================================================
  RCS file: /home/cvs/db-ojb/xdocs/query.xml,v
  retrieving revision 1.12
  retrieving revision 1.13
  diff -u -r1.12 -r1.13
  --- query.xml	6 Jan 2003 14:09:20 -0000	1.12
  +++ query.xml	16 Feb 2003 13:24:32 -0000	1.13
  @@ -205,7 +205,7 @@
   
   <subsection name="joins">
   <p>
  -Joins resulting from path expressions ("relationship.attribute") in criteria are automatically
handled by OJB.
  +Joins resulting from <b>path expressions</b> ("relationship.attribute") in
criteria are automatically handled by OJB.
   Path expressions are supported for all relationships 1:1, 1:n and m:n (decomposed and non-decomposed)
   and can be nested.
   <br/><br/>
  @@ -255,6 +255,35 @@
   ]]></source>
   
   </p>
  +
  +<p>
  +If path expressions refer to a class having <b>extents</b>, the tables of the
extent classes participate in the JOIN and the criteria is ORed. The shown sample queries
all ProductGroups having an Article named 'F%'. 
  +The path expression 'allArticlesInGroup' refers to the class Articles which has two extents:
Books and CDs.
  +
  +<source><![CDATA[
  +Criteria crit = new Criteria();
  +crit.addLike("allArticlesInGroup.articleName", "F%");
  +Query q = QueryFactory.newQuery(ProductGroup.class, crit, true);
  +
  +Collection results = broker.getCollectionByQuery(q);
  +]]></source>
  +
  +<br/>
  +This sample produces the following SQL:
  +
  +<source><![CDATA[
  +SELECT DISTINCT A0.KategorieName,A0.Kategorie_Nr,A0.Beschreibung
  +FROM Kategorien A0 
  +INNER JOIN Artikel A1 ON A0.Kategorie_Nr=A1.Kategorie_Nr 
  +LEFT OUTER JOIN BOOKS A1E0 ON A0.Kategorie_Nr=A1E0.Kategorie_Nr 
  +LEFT OUTER JOIN CDS A1E1 ON A0.Kategorie_Nr=A1E1.Kategorie_Nr 
  +WHERE A1.Artikelname LIKE  'F%'  OR 
  +A1E0.Artikelname LIKE  'F%'  OR 
  +A1E1.Artikelname LIKE  'F%' 
  +]]></source>
  +
  +</p>
  +
   </subsection>
   
   <subsection name="prefetched relationships">
  
  
  

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