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| <title xmlns:d="http://docbook.org/ns/docbook">Chapter 2. Starting a project</title><link rel="stylesheet" type="text/css" href="css/cayenne-doc.css"><meta xmlns:d="http://docbook.org/ns/docbook" name="keywords" content="Cayenne 3.1 documentation"><meta xmlns:d="http://docbook.org/ns/docbook" name="description" content="User documentation for Apache Cayenne version 3.1"><link rel="home" href="index.html" title="Getting Started with Cayenne"><link rel="up" href="getting-started-part2.html" title="Part II. Learning mapping basics"><link rel="prev" href="getting-started-part2.html" title="Part II. Learning mapping basics"><link rel="next" href="ch03.html" title="Chapter 3. Getting started with Object Relational Mapping (ORM)"><script xmlns:d="http://docbook.org/ns/docbook" type="text/javascript"> | |
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| </script></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div xmlns:d="http://docbook.org/ns/docbook" class="navheader"><table width="100%" summary="Navigation header"><tr><th class="versioninfo">v.3.1 (3.1)</th><th align="center">Chapter 2. Starting a project</th><th></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="getting-started-part2.html">Prev</a> </td><th width="60%" align="center"><a accesskey="u" href="getting-started-part2.html">Part II. Learning mapping basics</a></th><td width="20%" align="right"> <a accesskey="n" href="ch03.html">Next</a></td></tr></table><hr></div><div class="chapter" title="Chapter 2. Starting a project"><div class="titlepage"><div><div><h2 class="title"><a name="d0e58"></a>Chapter 2. Starting a project</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="ch02.html#create-new-project">Create a new Project in Eclipse </a></span></dt><dt><span class="section"><a href="ch02.html#download-and-start-cayenne-modeler">Download and Start CayenneModeler</a></span></dt><dt><span class="section"><a href="ch02.html#create-new-mapping-project">Create a New Mapping Project in CayenneModeler</a></span></dt><dt><span class="section"><a href="ch02.html#create-datanode">Create a DataNode</a></span></dt><dt><span class="section"><a href="ch02.html#create-datamap">Create a DataMap</a></span></dt><dt><span class="section"><a href="ch02.html#save-project">Save the Project</a></span></dt></dl></div><p> | |
| The goal of this chapter is to create a new Java project in Eclipse | |
| containing a basic Cayenne mapping. It presents an introduction to | |
| CayenneModeler GUI tool, showing how to create the initial mapping | |
| objects: DataDomain, DataNode, DataMap. | |
| </p><div class="section" title="Create a new Project in Eclipse"><div class="titlepage"><div><div><h2 class="title"><a name="create-new-project"></a>Create a new Project in Eclipse </h2></div></div></div><p> | |
| In Eclipse select "File > New > Other..." and then "Maven > | |
| Maven Project". Click "Next". On the following screen check | |
| "Create a simple project" checkbox and click "Next" again. | |
| In the dialog shown on the screenshot below, fill the "Group Id" | |
| and "Artifact Id" fields and click "Finish". | |
| </p><p> | |
| <span class="inlinemediaobject"><img src="images/tutorial-eclipse-project.png"></span> | |
| </p><p> | |
| Now you should have a new empty project in the Eclipse workspace. | |
| Check that the project Java compiler settings are correct. Rightclick | |
| on the "tutorial" project, select "Properties > Java Compiler" and | |
| ensure that "Compiler compliance level" is at least "1.5" | |
| (some versions of Maven plugin seem to be setting it to 1.4 by default). | |
| </p></div><div class="section" title="Download and Start CayenneModeler"><div class="titlepage"><div><div><h2 class="title"><a name="download-and-start-cayenne-modeler"></a>Download and Start CayenneModeler</h2></div></div></div><p> | |
| Although later in this tutorial we'll be using Maven to include Cayenne | |
| runtime jars in the project, you'll still need to download Cayenne to | |
| get access to the CayenneModeler tool. | |
| </p><p> | |
| </p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>If you are really into Maven, you can start | |
| CayenneModeler from Maven too. We'll do it in a more traditional way | |
| here.</p></div><p> | |
| </p><p> Download the latest release. Unpack the distribution somewhere in the file system and | |
| start CayenneModeler, following platform-specific instructions. On most platforms it is | |
| done simply by doubleclicking the Modeler icon. The welcome screen of the Modeler looks | |
| like this: </p><p><span class="inlinemediaobject"><img src="images/modeler-started.png"></span></p></div><div class="section" title="Create a New Mapping Project in CayenneModeler"><div class="titlepage"><div><div><h2 class="title"><a name="create-new-mapping-project"></a>Create a New Mapping Project in CayenneModeler</h2></div></div></div><p>Click on the "New Project" button on Welcome screen. A new mapping project will appear | |
| that contains a single <span class="bold"><strong>DataDomain</strong></span>. The meaning of a | |
| DataDomain is explained elsewhere in the User Guide. For now it is sufficient to | |
| understand that DataDomain is the root of your mapping project.</p></div><div class="section" title="Create a DataNode"><div class="titlepage"><div><div><h2 class="title"><a name="create-datanode"></a>Create a DataNode</h2></div></div></div><p>The next project object you will create is a <span class="bold"><strong>DataNode</strong></span>. DataNode is a descriptor of a single database your application | |
| will connect to. Cayenne mapping project can use more than one database, but for now, | |
| we'll only use one. With "project" selected on the left, click on "Create DataNode" | |
| button on the toolbar (or select "Project > Create DataNode" from the menu.</p><p>A new DataNode is displayed. Now you need to specify JDBC connection parameters. For | |
| an in-memory Derby database you can enter the following settings: </p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p>JDBC Driver: org.apache.derby.jdbc.EmbeddedDriver</p></li><li class="listitem"><p>DB URL: jdbc:derby:memory:testdb;create=true</p></li></ul></div><p> | |
| </p><div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>We are creating an in-memory database here. So when | |
| you stop your application, all the data will be lost. In most real-life | |
| cases you'll be connecting to a database that actually persists its data on | |
| disk, but an in-memory DB will do for the simple tutorial.</p></div><p> | |
| </p><p>Also you will need to change "Schema Update Strategy". Select | |
| "org.apache.cayenne.access.dbsync.CreateIfNoSchemaStrategy" from the dropdown, so that | |
| Cayenne creates a new schema on Derby based on the ORM mapping when the application | |
| starts.</p><p><span class="inlinemediaobject"><img src="images/base-datanode.png"></span></p></div><div class="section" title="Create a DataMap"><div class="titlepage"><div><div><h2 class="title"><a name="create-datamap"></a>Create a DataMap</h2></div></div></div><p>Now you will create a <span class="bold"><strong>DataMap</strong></span>. DataMap is an object | |
| that holds all the mapping information. To create it, click on "Create DataMap" button | |
| (or select a corresponding menu item). Note that the newly created DataMap is | |
| automatically linked to the DataNode that you created in the previous step. If there is | |
| more than one DataNode, you may need to link a DataMap to the correct node manually. In | |
| other words a DataMap within DataDomain must point to a database described by the | |
| map.</p><p>You can leave all the DataMap defaults unchanged except for one - "Java Package". | |
| Enter "org.example.cayenne.persistent". This name will later be used for all persistent | |
| classes.</p><p><span class="inlinemediaobject"><img src="images/base-datamap.png"></span></p></div><div class="section" title="Save the Project"><div class="titlepage"><div><div><h2 class="title"><a name="save-project"></a>Save the Project</h2></div></div></div><p>Before you proceed with the actual mapping, let's save the project. Click on "Save" | |
| button in the toolbar and navigate to the "tutorial" Eclipse project folder that was | |
| created earlier in this section and its "src/main/resources" subfolder and save the | |
| project there. Now go back to Eclipse, right click on "tutorial" project and select | |
| "Refresh", you will see three Cayenne XML files.</p><p><span class="inlinemediaobject"><img src="images/eclipse-xmlfiles.png"></span></p><p>Note that the location of the XML files is not coincidental. Cayenne runtime looks for | |
| "cayenne-*.xml" file in the application CLASSPATH and "src/main/resources" folder should | |
| already be a "class folder" in Eclipse for our project (and is also a standard location | |
| that Maven would copy to a jar file, if we were using Maven from command-line).</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="getting-started-part2.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="getting-started-part2.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="ch03.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Part II. Learning mapping basics </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 3. Getting started with Object Relational Mapping (ORM)</td></tr></table></div></body></html> |