brj 2005/04/09 06:21:19
Modified: src/doc/forrest/src/documentation/content/xdocs/docu/guides
query.xml
Log:
short description of ReportQuery#setJdbcTypes
Revision Changes Path
1.5 +33 -9
db-ojb/src/doc/forrest/src/documentation/content/xdocs/docu/guides/query.xml
Index: query.xml
===================================================================
RCS file:
/home/cvs/db-ojb/src/doc/forrest/src/documentation/content/xdocs/docu/guides/query.xml,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- query.xml 9 Apr 2005 12:52:25 -0000 1.4
+++ query.xml 9 Apr 2005 13:21:19 -0000 1.5
@@ -188,9 +188,9 @@
Instead of using the primary keys of an object as a
selection criterion, <strong>addEqualToIdentity</strong>
supports the whole Identity. This feature leads to
more readable queries and is useful, when the object has multiple pk.
</p>
- <p>
+ <p>
The following sample looks for projects of a given
person. When querying for simple attributes we would use
- crit.addEqualTo("persons.id", personId); where id is
the primary key of person.
+ crit.addEqualTo("persons.id", personId); where id is
the primary key of person.
Criteria#addEqualToIdentity accepts the whole
Identity and translates it into an addEqualTo() for each primary key.
</p>
<source><![CDATA[
@@ -666,8 +666,7 @@
Report queries are used to retrieve row data, not 'real'
business objects. A row is an array of Object.
With these queries you can define what attributes of an
object you want to have in the row.
The attribute names may also contain path expressions like
'owner.address.street'.
- To define the attributes use ReportQuery
- <strong>#setAttributes(String[] attributes)</strong>.
+ To define the attributes use
ReportQuery#<strong>setAttributes(String[] attributes)</strong>.
</p>
<p>
The following ReportQuery retrieves the name of the
ProductGroup, the name of the Article etc. for all
@@ -687,15 +686,40 @@
Object[4] ([String, Integer, String, Double]).
</p>
+ <section>
+ <title>Defining the type of the returned data</title>
+ <p>
+ In the above example the ReportQuery returned a
Collection of [String, Integer, String, Double]. The types of the returned
+ data are defined by the Metadata of the underlying
Resultset. OJB lets you control the type of the returned data of ReportQueries
+ with the method
ReportQuery#<strong>setJdbcTypes</strong>(int[] jdbcTypes).
+ SetJdbcTypes expects a type for each selected
attributes.
+ </p>
+ <source><![CDATA[
+int types[] = new int[]{Types.DECIMAL, Types.VARCHAR, Types.BIGINT};
+Criteria crit = new Criteria();
+crit.addLike("firstname", "%o%");
+
+ReportQueryByCriteria q = ojb.getQueryFactory().newReportQuery(Person.class,
crit);
+q.setAttributes(new String[]{"id", "firstname", "count(*)"});
+q.setJdbcTypes(types);
+
+Iterator iter = broker.getReportQueryIteratorByQuery(q);
+]]></source>
+
+ </section>
+
<section>
<title>Limitations of Report Queries</title>
<p>
- ReportQueries currently only support simple arithmetic
expressions (ie. price * 1.05).
- Expressions based on multiple attributes (ie. price -
bonus) do not work.
+ ReportQueries (OJB 1.0.x) only support simple arithmetic
expressions (ie. price * 1.05).
+ In OJB 1.1 the support for expressions based on multiple
attributes (ie. price - bonus) has been extended,
+ but they only work when all attributes belong to the same
class.
+ This limitation applies to all QueryByCriteria.
</p>
<p>
- ReportQueries should not be used with columns referencing
classes with extents. Assume we want to select all ProductGroups
- and summarize the amount and prize of items in stock per
group. The class Article referenced by <strong>allArticlesInGroup</strong>
has the extents Books and CDs.
+ ReportQueries are <strong>not extent aware</strong> and
should therefore not be used with columns referencing classes with extents.
+ Assume we want to select all ProductGroups and summarize
the amount and prize of items in stock per group.
+ The class Article referenced by
<strong>allArticlesInGroup</strong>has the extents Books and CDs.
</p>
<source><![CDATA[
Criteria crit = new Criteria();
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