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From arm...@apache.org
Subject cvs commit: jakarta-ojb/xdocs faq.xml performance.xml
Date Fri, 31 Jan 2003 17:42:45 GMT
arminw      2003/01/31 09:42:45

  Modified:    xdocs    faq.xml performance.xml
  Log:
  add more faq, correct document view
  
  Revision  Changes    Path
  1.13      +274 -11   jakarta-ojb/xdocs/faq.xml
  
  Index: faq.xml
  ===================================================================
  RCS file: /home/cvs/jakarta-ojb/xdocs/faq.xml,v
  retrieving revision 1.12
  retrieving revision 1.13
  diff -u -r1.12 -r1.13
  --- faq.xml	31 Jan 2003 06:56:49 -0000	1.12
  +++ faq.xml	31 Jan 2003 17:42:44 -0000	1.13
  @@ -4,6 +4,7 @@
    <properties>
     <author email="thma@apache.org">Thomas Mahler</author>
     <author email="tobrien@transolutions.net">Tim O'Brien</author>
  +  <author>Armin Waibel</author>
     <title>ObJectRelationalBridge FAQ</title>
    </properties>
   
  @@ -16,9 +17,9 @@
       <li><a href="#8">How is OJB related to ODMG and JDO?</a></li>
       <li><a href="#17">What are the OJB design principals?</a></li>
       <li><a href="#18">Where can I learn more about Object/Relational mapping
in general?</a></li>
  -  
  +
     </ul>
  -  
  +
     <p><b>Getting started</b></p>
      <ul>
       <li><a href="#1">Help! I'm having problems installing and using OJB!</a></li>
  @@ -26,19 +27,20 @@
       <li><a href="#4">Does OJB support my RDBMS?</a></li>
       <li><a href="#10">What are the OJB internal tables for?</a></li>
   
  -	</ul> 
  -	 
  +	</ul>
  +
     <p><b>OJB APIs</b></p>
     <ul>
       <li><a href="#9">What are the differences between the PersistenceBroker
API and the ODMG API? Which one should I use in my applications?</a></li>
       <li><a href="#15">I don't like OQL, can I use the PersistenceBroker Queries
within ODMG?</a></li>
       <li><a href="#16">The OJB JDO implementation is not finished, how can I
start using OJB?</a></li>
  -  
  +
     </ul>
  -  
  -  <p><b>Howto</b></p>  
  +
  +  <p><b>Howto</b></p>
     <ul>
       <li><a href="#5">How to use OJB with my RDBMS?</a></li>
  +    <li><a href="#32">What the best settings for maximal performance?</a></li>
       <li><a href="#6">How to page and sort?</a></li>
       <li><a href="#7">What about performance and memory usage if thousands of
objects matching a query are returned as a Collection?</a></li>
       <li><a href="#11">When is it helpful to use Proxy Classes?</a></li>
  @@ -46,7 +48,20 @@
       <li><a href="#13">How can I trace and/or profile SQL statements executed
by OJB?</a></li>
       <li><a href="#14">How does OJB manage foreign keys?</a></li>
       <li><a href="#19">How can Collections of primitive typed elements be mapped?</a></li>
  -    
  +
  +    <li><a href="#20">How could class 'myClass' represent a collection of 'myClass'
objects</a></li>
  +    <li><a href="#21">Many different database user - How do they login?</a></li>
  +    <li><a href="#22">How do I use multiple databases within OJB?</a></li>
  +    <li><a href="#23">How does OJB handle connection pooling?</a></li>
  +    <li><a href="#24">Can I directly obtain a <code>java.sql.Connection</code>
within OJB?</a></li>
  +    <li><a href="#25">Is it possible to perform my own sql-queries in OJB?</a></li>
  +    <li><a href="#31">Start OJB without a repository file?</a></li>
  +    <li><a href="#26">Connect to database at runtime?</a></li>
  +    <li><a href="#27">Add new persistent objects (<code>class-descriptor</code>)
at runtime?</a></li>
  +    <li><a href="#28">Global metadata changes at runtime?</a></li>
  +    <li><a href="#29">Per thread metadata changes at runtime?</a></li>
  +    <li><a href="#30">Is it possible to use OJB within EJB's?</a></li>
  +
      </ul>
   
      <subsection name="Help! I'm having problems installing and using OJB!" anchor="1">
  @@ -222,7 +237,7 @@
   
      <subsection name="What are the OJB design principals?" anchor="17">
       <p>
  -    OJB has a "pattern driven" design. 
  +    OJB has a "pattern driven" design.
       <a href="links.html#design">Please refer to this document for more details</a>
       </p>
      </subsection>
  @@ -236,12 +251,12 @@
      <subsection name="How can Collections of primitive typed elements be mapped?" anchor="19">
       <p>
   		The first thing to ask is:
  -		How are these primitive typed elements (Strings are also treated as primitive types here)

  +		How are these primitive typed elements (Strings are also treated as primitive types here)
   		stored in the database.<br/>
   		1) are they treated as ordinary domain objects and stored in a separate table?<br/>
   		2) are they serialized into a Varchar field?<br/>
   		3) are they stored as a comma separated varchar field?<br/>
  -		4) is each element of the vector or array stored in a separate column? 
  +		4) is each element of the vector or array stored in a separate column?
   		(this solution does only work for a fixed number of elements!)<br/>
   		<br/>
   		Follow these steps for solution 3):<br/>
  @@ -266,6 +281,42 @@
       </p>
      </subsection>
   
  +
  +   <subsection name="What are the best settings for maximal performance?" anchor="32">
  +    <p>
  +    We don't know, that depends from the environment OJB runs (hardware, database, driver,
application server, ...).
  +    But there are some settings which affect the performance:
  +    <ul>
  +        <li>The API you use, e.g. PB-api is much faster then the ODMG-api. See <a
href="#9">which API</a> for more information</li>
  +        <li>PersistenceBroker pool size. See <a href="OJB.properties.txt">OJB.properties</a>
for more information.</li>
  +        <li>Used sequence manager implementation. See <a href="sequencemanager.html">sequence
manager</a> for more information.</li>
  +        <li>ConnectionFactory implementation / Connection pooling. See <a href="#23">connection
pooling</a> for more information.</li>
  +        <li>Use of batch mode (when supported by the DB). See <a href="repository.dtd.txt">repository.dtd</a>
for more information.</li>
  +    </ul>
  +    </p>
  +    <p>
  +    To test the different settings OJB was shipped with a small performance
  +    test suite, call
  +    <code>bin\build.bat <font color="red">xxx</font></code> or
  +    <code>bin/build.sh <font color="red">xxx</font></code> with
xxx:
  +    <ul>
  +        <li><code>performance</code>
  +        <br/>
  +        This test compare the OJB api's with direct JDBC calls. To change the programm
  +        parameters see <code>build.xml</code> target <code>performance</code>.
  +        </li>
  +        <li><code>performance2</code>
  +        <br/>
  +        This test checks the multi-threaded performance of OJB. To change the programm
  +        parameters see <code>build.xml</code> target <code>performance2</code>.
It's also
  +        possible to run this test standalone, see javadocs <code>org.apache.ojb.broker.Performance2</code>
  +        </li>
  +    </ul>
  +    See for further information <a href="performance.html">performance</a>
section.
  +    </p>
  +    </subsection>
  +
  +
      <subsection name="How to page and sort?" anchor="6">
       <p>
        Sorting can be configured by
  @@ -501,6 +552,7 @@
      </subsection>
   
   
  +
      <subsection name="How can I trace and/or profile SQL statements executed by OJB?"
anchor="13">
       <p>
      	 OJB  ships with out of the box support for P6Spy.
  @@ -645,6 +697,217 @@
   	 Making it work with OJB-JDO will be easy!
       </p>
      </subsection>
  +
  +<subsection name="How could class 'myClass' represent a collection of 'myClass' objects"
anchor="20">
  +   <p>
  +    OJB can handle such recursive associations without problems.
  +    <ul>
  +    <li>
  +    add a collection attribute 'myClasses' to the class <code>myClass</code>
  +    this collection will hold the associated <code>myClass</code> objects.
  +    </li>
  +    <li>
  +    you have to decide wether this assosciation is 1:n or m:n.
  +    <br/>
  +    for 1:n you just need an additional foreignkey attribute in the MY_CLASS
  +    table. Of course you'll also need a matching attribute in the class <code>myClass</code>.
  +    <br/>
  +    For a m:n association you'll have to define a intermediary table to hold the
  +    mapping entries.
  +    </li>
  +    <li>
  +    define a <code>collection-descriptor</code> tag in the <code>class-descriptor</code>
  +    of <code>myClass</code> in repository.xml.
  +    Follow the steps in <A HREF="tutorial3.html">tutorial3.html</A> on 1:n
and m:n.
  +    </li>
  +    </ul>
  +   </p>
  +   </subsection>
  +
  +
  +    <subsection name="Many different database user - How do they login?" anchor="21">
  +    <p>
  +    There are two ways to do that. Define for each user a <code>jdbc-connection-descriptor</code>
  +    (unattractive way, because we have to add each new user to repository file),
  +    or let OJB handle this for you.
  +    <br/>
  +    For it define <b>one</b> <code>jdbc-connection-descriptor</code>,
  +    now you can use the same <code>jcdAlias</code> name with different <code>User/Password</code>.
OJB
  +    <b>copy</b> the defined <code>jdbc-connection-descriptor</code>
and replace the <code>username</code>
  +    and <code>password</code> with the given <code>User/Password</code>.
Keep in mind, when the
  +    <code>connection-pool</code> element enables connection pooling, every
user get its separate pool.
  +    See <a HREF="#23">How does OJB handle connection pooling</a>.
  +    </p>
  +    </subsection>
  +
  +
  +    <subsection name="How do I use multiple databases within OJB?" anchor="22">
  +    <p>
  +    Define for each database a <code>jdbc-connection-descriptor</code>, use
the
  +    different <code>jcdAlias</code> names to match the according database.
  +    </p>
  +    </subsection>
  +
  +
  +    <subsection name="How does OJB handle connection pooling?" anchor="23">
  +    <p>
  +    OJB does connection pooling per default, expect for datasources. Datasources never
will be pooled.
  +    <br/>
  +    Responsible for managing the connections in OJB are implementations of the
  +    <code>org.apache.ojb.broker.accesslayer.ConnectionFactory.java</code>
  +    interface. There are several implementations shipped with OJB called
  +    <code>org.apache.ojb.broker.accesslayer.ConnectionFactoryXXXImpl.java</code>.
  +    You can find among other things a none pooling implementation and a implementation
  +    using jakarta-DBCP api.
  +    <br/>
  +    To manage the connection pooling define in your <code>jdbc-connection-descriptor</code>
a
  +    <code>connection-pool</code> element. Here you can specify which <code>ConnectionFactory</code>
implementation
  +    should be used. More info see <a HREF="repository.html">repository section</a>
  +    or <a HREF="repository.dtd.txt">repository.dtd</a>.
  +    </p>
  +    </subsection>
  +
  +
  +    <subsection name="Can I directly obtain a java.sql.Connection within OJB?" anchor="24">
  +    <p>
  +    The PB-api enabled the possibility to obtain a connection from the current
  +    used <code>PersistenceBroker</code> instance:
  +    <source>
  +PersistenceBroker broker = PersistenceBrokerFactory.
  +                                createPersistenceBroker(myKey);
  +broker.beginTransaction();
  +// do something
  +
  +Connection con = broker.serviceConnectionManager().getConnection();
  +// perform your connction action and do more
  +
  +broker.commitTransaction();
  +broker.close();
  +    </source>
  +    Do not close or commit the connection, this will be done by OJB.
  +    See ditto <a href="#25">perform sql queries</a>.
  +    </p>
  +    </subsection>
  +
  +
  +    <subsection name="Is it possible to perform my own sql-queries in OJB?" anchor="25">
  +    <p>
  +    There are serveral ways in OJB to do that.
  +    <br/>
  +    If you completely want to bypass the OJB
  +    query-api see <a href="#21">direct connection use</a>.
  +    <br/>
  +    A more elegant way is to use a <code>QueryBySQL</code> object:
  +    <source>
  +String sql =
  +        "SELECT A.Artikel_Nr FROM Artikel A, Kategorien PG"
  +        + " WHERE A.Kategorie_Nr = PG.Kategorie_Nr"
  +        + " AND PG.Kategorie_Nr = 2";
  +// get the QueryBySQL
  +Query q2 = QueryFactory.newQuery(Article.class, sql);
  +
  +Iterator iter2 = broker.getIteratorByQuery(q2);
  +// or
  +Collection col2 = broker.getCollectionByQuery(q2);
  +    </source>
  +    </p>
  +    </subsection>
  +
  +
  +    <subsection name="Start OJB without a repository file?" anchor="31">
  +    <p>
  +    It is possible to start OJB with an 'empty' repository.xml file:
  +    <source><![CDATA[
  +<?xml version="1.0" encoding="UTF-8"?>
  +<!DOCTYPE descriptor-repository SYSTEM "repository.dtd">
  +
  +<descriptor-repository version="0.9.9" isolation-level="read-uncommitted">
  +
  +</descriptor-repository>
  +    ]]></source>
  +    Now you have to declare the <code>jdbc-connection-descriptor</code> and
  +    <code>class-descriptor</code> at runtime. See <a href="#26">Connect
to database at
  +    runtime</a> and <a href="#27">Add a new persistent object (class-descriptor)
at runtime</a>
  +    for more information.
  +    </p>
  +    </subsection>
  +
  +
  +
  +    <subsection name="Connect to database at runtime?" anchor="26">
  +    <p>
  +    You could add <code>jdbc-connection-descriptors</code> at runtime, using
  +    the <code>MetadataManager</code>:
  +    <source>
  +ConnectionRepository cr = MetadataManager.
  +                            getInstance().connectionRepository();
  +
  +JdbcConnectionDescriptor jcd = new JdbcConnectionDescriptor();
  +jcd.setJcdAlias("testConnection")
  +jcd.setUserName("sa");
  +jcd.setPassword("sa");
  +jcd.setDbAlias("aAlias");
  +jcd.setDbms("aDatabase");
  +// .... the other required setter
  +
  +// add new descriptor
  +cr.addDescriptor(jcd);
  +
  +// Now it's possible to obtain a PB-instance
  +PBKey key = new PBKey("testConnection", "sa", "sa");
  +PersistenceBroker broker = PersistenceBrokerFactory.
  +                            createPersistenceBroker(key);
  +    </source>
  +    </p>
  +    </subsection>
  +
  +
  +    <subsection name="Add a new persistent object (class-descriptor) at runtime?" anchor="27">
  +    <p>
  +    You could add <code>class-descriptors</code> at runtime, using
  +    the <code>MetadataManager</code>:
  +    <source>
  +DescriptorRepository dr = MetadataManager.
  +                            getInstance().getRepository();
  +
  +ClassDescriptor cld = new ClassDescriptor(dr);
  +cld.setClassOfObject(A.class);
  +//.... other setter
  +
  +// add the fields of the class
  +FieldDescriptor fd = new FieldDescriptor(cld, 1);
  +fd.setPersistentField(A.class, "someAField");
  +cld.addFieldDescriptor(fd);
  +
  +// now we add the the class descriptor
  +dr.setClassDescriptor(cld);
  +    </source>
  +    </p>
  +    </subsection>
  +
  +
  +    <subsection name="Global metadata changes at runtime?" anchor="28">
  +    <p>
  +    TODO
  +    </p>
  +    </subsection>
  +
  +    <subsection name="Per thread metadata changes at runtime?" anchor="29">
  +    <p>
  +    TODO
  +    </p>
  +    </subsection>
  +
  +    <subsection name="Is it possible to use OJB within EJB's?" anchor="30">
  +    <p>
  +    Yes, see <a href="deployment.html">deployment</a> instructions in the docs.
  +    Additional you can find some EJB example beans in package <code>org.apache.ojb.ejb</code>
  +    under <code>[jakarta-ojb]/src/ejb</code>.
  +    </p>
  +    </subsection>
  +
  +
  +
     </section>
    </body>
   </document>
  
  
  
  1.5       +4 -2      jakarta-ojb/xdocs/performance.xml
  
  Index: performance.xml
  ===================================================================
  RCS file: /home/cvs/jakarta-ojb/xdocs/performance.xml,v
  retrieving revision 1.4
  retrieving revision 1.5
  diff -u -r1.4 -r1.5
  --- performance.xml	12 Sep 2002 20:41:39 -0000	1.4
  +++ performance.xml	31 Jan 2003 17:42:44 -0000	1.5
  @@ -61,7 +61,8 @@
   the Hypersonic SQL shipped with OJB. A typical output looks like
   follows:</P>
   <PRE>performance:
  -      [ojb] [BOOT] INFO: OJB.properties: file:/home/tom/ojb-1-0/build/test/ojb/OJB.properties
  +      [ojb] [BOOT] INFO: OJB.properties:
  +      file:/home/tom/ojb-1-0/build/test/ojb/OJB.properties
         [ojb] .[performance] INFO:
         [ojb] [performance] INFO: inserting 10000 Objects: 6374 msec
         [ojb] [performance] INFO: updating 10000 Objects: 6083 msec
  @@ -88,7 +89,8 @@
         [ojb]
         [ojb] OK (1 tests)
         [ojb]
  -     [jdbc] [BOOT] INFO: OJB.properties: file:/home/tom/ojb-1-0/build/test/ojb/OJB.properties
  +     [jdbc] [BOOT] INFO: OJB.properties:
  +     file:/home/tom/ojb-1-0/build/test/ojb/OJB.properties
        [jdbc] .[performance] INFO:
        [jdbc] [performance] INFO: inserting 10000 Objects: 2494 msec
        [jdbc] [performance] INFO: updating 10000 Objects: 3229 msec
  
  
  

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