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| author | coreyg <coreyg@13f79535-47bb-0310-9956-ffa450edef68> | 2014-11-21 09:30:19 +0000 |
|---|---|---|
| committer | coreyg <coreyg@13f79535-47bb-0310-9956-ffa450edef68> | 2014-11-21 09:30:19 +0000 |
| commit | 200a40b332420f94992eb39a6d0ea1cf1490ffc4 (patch) | |
| tree | 1c76ef1d254c7bfc91128a313d319bd60da9d01e /site/trunk/site-publish/rdb-das-c-conventionoverconfiguration.html | |
| parent | 85f53ab6ab4f664d63774c94b672a875c9e52b8a (diff) | |
Adding tuscany's website to their svn repo for svnpubsub
git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1640879 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'site/trunk/site-publish/rdb-das-c-conventionoverconfiguration.html')
| -rw-r--r-- | site/trunk/site-publish/rdb-das-c-conventionoverconfiguration.html | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/site/trunk/site-publish/rdb-das-c-conventionoverconfiguration.html b/site/trunk/site-publish/rdb-das-c-conventionoverconfiguration.html new file mode 100644 index 0000000000..025a465e0b --- /dev/null +++ b/site/trunk/site-publish/rdb-das-c-conventionoverconfiguration.html @@ -0,0 +1,119 @@ + +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<HTML> + <HEAD> + <LINK type="text/css" rel="stylesheet" href="http://incubator.apache.org/tuscany/stylesheets/default.css"> + <LINK rel="SHORTCUT ICON" href="http://cwiki.apache.org/confluence/pages/$images/favicon.ico"> + <TITLE>RDB DAS C++ - ConventionOverConfiguration : Apache Tuscany</TITLE> + <META http-equiv="Content-Type" content="text/html;charset=UTF-8"></HEAD> + + <BODY onload="init()"> + + <TABLE valign="top" border="0" cellspacing="0" cellpadding="0" width="100%" background="http://incubator.apache.org/tuscany/images/TuscanyLogoNEW_Text_120px_bg.jpg"> + <TR> + <TD valing="top" align="left"> + <A href="http://cwiki.apache.org/confluence/pages/$siteroot"><IMG src="http://incubator.apache.org/tuscany/images/TuscanyLogoNEW_Text_120px_bg.jpg" height="91" width="25" border="0"></A> + </TD> + <TD> + <A href="http://incubator.apache.org/tuscany/"><IMG src="http://incubator.apache.org/tuscany/images/TuscanyLogo.jpg" border="0"></A> + </TD> + + <TD width="100%"> + + </TD> + <TD align="right"> + <IMG src="http://incubator.apache.org/tuscany/images/apache-incubator-logo.png" border="0"> + </TD> + + <!-- Adds the edit page link to the top banner--> + <TD valign="bottom"> + <DIV style="padding: 2px 10px; margin: 0px;"> + <A href="http://cwiki.apache.org/confluence/pages/editpage.action?pageId=69443"> + <IMG src="http://incubator.apache.org/tuscany/images/notep_16.gif" height="16" width="16" border="0" align="absmiddle" title="Edit Page"></A> + </DIV> + </TD> + + </TR> + </TABLE> + + <TABLE border="0" cellpadding="2" cellspacing="0" width="100%"> + <TR class="topBar"> + <TD align="left" valign="middle" class="topBarDiv" nowrap="true" width="100%"> + <A href="home.html" title="Apache Tuscany">Apache Tuscany</A> > <A href="home.html" title="Home">Home</A> > <A href="das-overview.html" title="DAS Overview">DAS Overview</A> > <A href="das-c.html" title="DAS C++">DAS C++</A> > <A href="das-c-documentation-menu.html" title="DAS C++ Documentation Menu">DAS C++ Documentation Menu</A> > <A href="rdb-das-c-user-guide.html" title="RDB DAS C++ - User Guide">RDB DAS C++ - User Guide</A> > <A href="" title="RDB DAS C++ - ConventionOverConfiguration">RDB DAS C++ - ConventionOverConfiguration</A> + </TD> + + <TD align="left" valign="middle" class="topBarDiv" nowrap="true"> + <A href="http://mail-archives.apache.org/mod_mbox/ws-tuscany-user">User List</A> | <A href="http://mail-archives.apache.org/mod_mbox/ws-tuscany-dev">Dev List</A> | <A href="http://issues.apache.org/jira/browse/Tuscany">Issue Tracker</A> + </TD> + </TR> + </TABLE> + + <TABLE border="0" cellpadding="0" width="100%" bgcolor="#FFFFFF"> + <TR> + <TD align="left" valign="top"> + <DIV id="PageContent"> + + <DIV class="pagecontent"> + <DIV class="wiki-content"> + <H1><A name="RDBDASC%2B%2B-ConventionOverConfiguration-ConventionOverConfiguration"></A>ConventionOverConfiguration</H1> + +<P>This concept reflects the notion that configuration (defining a bunch of stuff in a side file) can be avoided by following convention (adhering to prescribed patterns) and that this is generally a good thing. The RDB DAS has several reasonable conventions in place and using these can significantly reduce a developer's work-load.</P> + +<P>As an example, the RDB DAS provides a straight-forward, one-to-one mapping of database tables to DataObject Types and from table columns to DataObject properties. If a user provides no mapping information to the contrary, a graph of DataObjects returned by the DAS will directly map Types/Properties to the Tables/Columns queried.</P> + +<P>For example, consider a database with the following table:</P> +<DIV class="code"><DIV class="codeContent"> +<PRE class="code-java">TABLE CUSTOMER + ID INTEGER + LASTNAME VARCHAR(20) + ADDRESS VARCHAR(30)</PRE> +</DIV></DIV> +<P>If an application uses the DAS to query this table with the following SQL statement:</P> +<DIV class="preformatted"><DIV class="preformattedContent"> +<PRE>SELECT * FROM CUSTOMER +</PRE> +</DIV></DIV> +<P>The DAS will return a graph of DataObjects each of Type CUSTOMER and each instance in will have three properties: (ID, LASTNAME, ADDRESS). Here is the example code. Note that no configuration data is provided at all.</P> +<DIV class="panel"><DIV class="panelContent"> +<P>DASImpl* das = (DASImpl*) DASImpl::getFactory().createDAS(getConnection());<BR> + CommandPtr readCustomers = das->createCommand("select * from CUSTOMER");<BR> + DataObjectPtr root = readCustomers->executeQuery();</P> +</DIV></DIV> +<P>Another piece of convention followed by the RDB DAS has to do with database table keys. When asked to "apply changes", the RDB DAS scans the SDO ChangeSummery and generates the set of INSERT/UPDATE and DELETE statements needed to flush the graph changes to the database. To generate the correct statements the RDB DAS needs to know how a DataObject's properties map to a database table key. In typical Object/Relational mappings frameworks, this information is provided in a config file with something like this:</P> +<DIV class="preformatted"><DIV class="preformattedContent"> +<PRE><Table tableName="COMPANY"> + <Column columnName="ID" primaryKey="true"/> + . + . + . + </Table> +</PRE> +</DIV></DIV> +<P>However, the RDB DAS understands is that, in the absence of user provided cofiguration data, a DataObject property named "ID" maps to a key column named "ID" in the database. If a developer follows this convention (naming key columns "ID") then this key-mapping information need not be specified in a configuration file. Convention Over Configuration strings are not case sensitives, so "ID", "Id", "iD" or"id" will be mapped as a primary key.</P> + + +<P>The RDB DAS also has convention in place for mapping DataObject relationships. If a database table (yyy) has a column named xxx_ID then the DAS will assume, in the absence of config data to the contrary, that there is a one-to-many relationship from table xxx to table yyy and that the key column for table xxx is named "ID".</P> + +<P>There is more "convention over configuration" coming. We are currently looking into support for optimistic concurrency control conventions and other areas. </P> + </DIV> + </DIV> + </DIV> + </TD> + </TR> + </TABLE> + + <SCRIPT src="http://www.google-analytics.com/urchin.js" type="text/javascript"> + </SCRIPT> + <SCRIPT type="text/javascript"> + _uacct = "UA-1174707-5"; + urchinTracker(); + </SCRIPT> + + <A href="http://www.statcounter.com/" target="_blank"><IMG src="http://c26.statcounter.com/counter.php?sc_project=2619156&java=0&security=94bd7e7d&invisible=0" alt="website stats" border="0"></A> + + <DIV class="footer"> + Copyright © 2003-2007, The Apache Software Foundation + </DIV> + + </BODY> +</HTML>
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