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| syeshin | 17ed4a6 | 2005-07-25 17:10:24 +0000 | [diff] [blame] | 7 | <title>Editing a group node</title> |
| syeshin | 15e1cc4 | 2005-08-26 04:13:17 +0000 | [diff] [blame^] | 8 | </head> |
| syeshin | 17ed4a6 | 2005-07-25 17:10:24 +0000 | [diff] [blame] | 9 | <body id="tedtgnde"><a name="tedtgnde"><!-- --></a> |
| 10 | |
| 11 | <h1 class="topictitle1">Editing a group node</h1> |
| 12 | <div><p>If your element has either element content or mixed content, its |
| 13 | content model is represented by a group node. You can add children elements |
| 14 | or another group to a group node, and specify how often, and |
| 15 | in what manner a group of elements will be available in an XML file associated |
| 16 | with your DTD.</p><div class="skipspace"><p></p> |
| 17 | <p>The following instructions were written for the Resource |
| 18 | perspective, but they will also work in many other perspectives. </p> |
| 19 | <p>To |
| 20 | edit a group node, follow these steps:</p> |
| 21 | </div> |
| 22 | <ol><li class="skipspace"><span>Open your DTD in the DTD editor.</span></li> |
| 23 | <li class="skipspace"><span>In the Outline view, expand the tree of the element you want to |
| 24 | work with.</span></li> |
| 25 | <li class="skipspace"><span>Click the group node you want to work with.</span></li> |
| 26 | <li class="skipspace"><span>In the Design view, select <span class="uicontrol">Sequence</span> or <span class="uicontrol">Choice</span> from |
| 27 | the <span class="uicontrol">Model Group</span> list.</span> This specifies whether |
| 28 | the group of elements are sorted in sequence or are available as a choice |
| 29 | in an XML file </li> |
| 30 | <li class="skipspace"><span>Select the appropriate option from the <span class="uicontrol">Occurrence</span> list |
| 31 | to indicate how often the group of elements can occur in an XML file associated |
| 32 | with this DTD. </span></li> |
| 33 | <li class="skipspace"><span>To add another existing element to a group as a child, right-click |
| 34 | the group node, click <span class="uicontrol">Add Element to Content Model</span>, |
| 35 | and specify its name.</span></li> |
| 36 | <li class="skipspace"><span>You can also add a group to an existing group node, by right-clicking |
| 37 | the group note and clicking <span class="uicontrol">Add Group to Content Model</span></span></li> |
| 38 | </ol> |
| 39 | <div class="skipspace"><p> <b>Note:</b>The <span class="uicontrol">Occurrence</span> option for the |
| 40 | group node only specifies how often the entire group of elements can occur |
| 41 | in an XML file. For each child element contained in the group, you can also |
| 42 | specify how often it can occur (that is, how often a child element can occur |
| 43 | is completely separate from how the often the group that contains it can occur).</p> |
| 44 | <p> <b>Tip:</b>: |
| 45 | To change the order of elements listed below a group node, simply click the |
| 46 | element you want to move and drag it to the location you want it in.</p> |
| 47 | </div> |
| 48 | <div class="skipspace"><p><b>Creating a group node that contains a list of small pets</b></p> |
| 49 | <p>The |
| 50 | following steps show you how to create a group node that contains a list of |
| 51 | small pets and explains how the choices you select affect how your group node |
| 52 | (and the elements it contains) can be used in any XML files based on your |
| 53 | DTD file:</p> |
| 54 | <ol><li>Create a new DTD called <kbd class="userinput">Pets.dtd</kbd> and open it in |
| 55 | the DTD editor.</li> |
| 56 | <li>In the Outline view, right-click your DTD file, and create a new element <kbd class="userinput">SmallPets</kbd>. |
| 57 | Also create three more elements - <kbd class="userinput">Cats</kbd>,<kbd class="userinput">Dogs</kbd>, |
| 58 | and.<kbd class="userinput">Fish</kbd></li> |
| 59 | <li>Expand <span class="uicontrol">SmallPets</span> and select the <span class="uicontrol">EMPTY</span> content |
| 60 | model. Select <span class="uicontrol">Mixed Content</span> from the <span class="uicontrol">Content |
| 61 | type</span> list. This means your <span class="uicontrol">SmallPets</span> element |
| 62 | can contain both other elements and character data.</li> |
| 63 | <li>Your content model is now represented by a group node <img src="../images/XSDChoice.gif" />. |
| 64 | A #PCDATA element (for character data) and new child element are automatically |
| 65 | created below it. Select the <span class="uicontrol">newChild</span> and select |
| 66 | <span class="uicontrol">Dogs</span> in the <span class="uicontrol">Name</span> list.</li> |
| 67 | <li>Right-click the group node and click <span class="uicontrol">Add Element to Content |
| 68 | Model</span>. Select the new child node and select <span class="uicontrol">Cats</span> in |
| 69 | the <span class="uicontrol">Name</span> list.</li> |
| 70 | <li>Repeat the previous step and select <span class="uicontrol">Fish</span> in the <span class="uicontrol">Name</span> list.</li> |
| 71 | <li>Now that you have created your list of small pets, you have to decide |
| 72 | if you want users to be able to select all of them or just one of them in |
| 73 | an XML file based on this Pets.dtd file. For example, you create a new XML |
| 74 | file called <kbd class="userinput">Pets.xml</kbd> based on this DTD, and you create |
| 75 | a <kbd class="userinput">SmallPets</kbd> element in it. If you selected <span class="uicontrol">Sequence</span> as |
| 76 | the model group in the DTD file, then you can have all of the small pets ( <span class="uicontrol">Cats</span>, |
| 77 | <span class="uicontrol">Dogs</span> and <span class="uicontrol">Fish</span>) in your <span class="uicontrol">SmallPets</span> element |
| 78 | in the <span class="uicontrol">Pets.xml</span> file. If, however, you selected <span class="uicontrol">Choice</span> as |
| 79 | the connector type, you can only have one animal listed in your <span class="uicontrol">SmallPets</span> element |
| 80 | in the <span class="uicontrol">Pets.xml</span> file. You can have <span class="uicontrol">Cats</span> or |
| 81 | <span class="uicontrol">Dogs</span> or <span class="uicontrol">Fish</span>, but you can |
| 82 | only have one at a time.</li> |
| 83 | <li>Now you have to decide how often this group of elements (the list of small |
| 84 | pets) can occur in an XML file associated with this DTD. You can specify |
| 85 | that it must appear only once ( <span class="uicontrol">Just once</span>), that it |
| 86 | must appear one or more times ( <span class="uicontrol">One or more</span>), that |
| 87 | it does not have to appear at all ( <span class="uicontrol">Optional</span>) or that |
| 88 | it might not be used at all or might be used any number of times ( <span class="uicontrol">Zero |
| 89 | or more</span>). <span class="uicontrol">Note</span>: You can also specify how |
| 90 | often each child element can occur. How often a child element can occur is |
| 91 | completely separate from how the often the group that contains it can occur. |
| 92 | So, for example, you can specify that the <span class="uicontrol">SmallPets</span> group |
| 93 | can occur <span class="uicontrol">Just once</span>, but the Cats element can appear |
| 94 | several times (to do this, select the <span class="uicontrol">Cats</span> element |
| 95 | and click <span class="uicontrol">One or more</span>).</li> |
| 96 | <li>The order in which you specify child elements in a group affects how they |
| 97 | can be used in any instances of the parent element in an XML file. For example, |
| 98 | if, in your DTD file, you had specified this: <samp class="codeph"><!ELEMENT SmallPets |
| 99 | (Dogs+ , Cats+ , Fish)+></samp>, any instances of<span class="uicontrol">SmallPets</span> in |
| 100 | your <span class="uicontrol">Pets.xml</span> file must contain one or more instances |
| 101 | of <span class="uicontrol">Dogs</span> followed by one or more instances of <span class="uicontrol">Cats</span>, |
| 102 | followed by just one occurrence of <span class="uicontrol">Fish</span>. You could |
| 103 | never have an occurrence of <span class="uicontrol">Fish</span> after <span class="uicontrol">Dogs</span> or <span class="uicontrol">Cats</span> before <span class="uicontrol">Dogs</span>. </li> |
| 104 | <li>You can also add a group to an existing group node. Select the node, right-click |
| 105 | it and click <span class="uicontrol">Add Group to Content Model</span>. You |
| 106 | might want to add a group node, if you decided you wanted to sort the animals |
| 107 | by breed into separate groups. </li> |
| 108 | </ol> |
| 109 | </div> |
| 110 | </div> |
| 111 | |
| 112 | <div> |
| 113 | <p> |
| 114 | <b class="parentlink">Parent topic:</b> <a href="../topics/tchgelm.html" title="An element's content model represents any data that can be contained inside or within the content of an element (that is, between the start and end tags of an element in an XML file). Editing an element's content model enables you to determine exactly what the element can (and cannot) contain.">Editing an element's content model</a><br /> |
| 115 | </p> |
| 116 | </div><p> |
| 117 | (C) Copyright IBM Corporation 2000, 2005. All Rights Reserved. |
| 118 | </p> |
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