1. XRX Basic CRUD Create, Read, Update and Delete XML Data Date: 10/1/2008
Dan McCreary
President
Dan McCreary & Associates
(952) M D
Metadata Solutions

2. Copyright 2008 Dan McCreary & Associates
Outline
Create new XML records using XForms
assigning sequential ids to each item (save-new.xq)
Listing items
Creating a list of current items (list-items.xq)
Reading XML records
creating read-only views of items (view-item.xq)
Update existing records
use XQuery updates (update.xq)
Deleting an item
How to delete with confirmation (delete-confirm.xq)
Searching
How to build custom search forms
Copyright 2008 Dan McCreary & Associates

3. Architecturally Significant Functions
Once you learn the basics CRUD(S) functions you can start to customize the item-manager code (S is for Search)
Additional functions don’t require you to learn any additional architectural features
Copyright 2008 Dan McCreary & Associates

4. Copyright 2008 Dan McCreary & Associates
Sample Item
To keep our examples simple, we are going to use a very simple “item” structure
<item>
<id>47</id>
<name>Item Forty Seven</name>
<description>This is a detailed description of item 47.</description>
<category>medium</category>
<status>draft</status>
<tag>tag-1</tag>
</item>
Copyright 2008 Dan McCreary & Associates

5. Copyright 2008 Dan McCreary & Associates
Folder Structure
/db
apps
item-manager
data
edit
search
views
1.xml
47.xml
new-instance.xml
search.xq
view-item.xq
2.xml
99.xml
next-id.xml
search.xhtml
list-items.xq
edit.xq
save-new.xq
update.xq
delete.xq
Copyright 2008 Dan McCreary & Associates

6. Copyright 2008 Dan McCreary & Associates
List Items
Simple for loop for all items in the data collection
Copyright 2008 Dan McCreary & Associates

7. Copyright 2008 Dan McCreary & Associates
list-items.xq
<table>
<thead>
<tr>
<th>ID</th>
<th>Name</th> …
</tr>
</thead>
<tbody>{
for $item in collection($collection)/item
let $id := $item/id/text()
return
<td>{$id}</td>
<td>{$item/name/text()}</td>
}</tbody></table>
Copyright 2008 Dan McCreary & Associates

8. Copyright 2008 Dan McCreary & Associates
Item Viewer
Always provide a read-only viewer for your items
Never force a person to use a write/lock edit form to view a document
This causes unnecessary locking in the database
Copyright 2008 Dan McCreary & Associates

9. Copyright 2008 Dan McCreary & Associates
view-item.xq
let $id := request:get-parameter('id', '') …
<h1>View Item</h1>
{let $item := collection($collection)/item[id = $id]
return
<table>
<tbody>
<tr><th>ID:</th><td>{$item/id/text()}</td></tr>
<tr><th>Name:</th><td>{$item/faq-category-id/text()}</td></tr>
<tr><th>Description:</th><td>{$item/description/text()}</td></tr>
<tr><th>Category:</th><td>{$item/category/text()}</td></tr>
<tr><th>Status:</th><td>{$item/status/text()}</td></tr>
<tr><th>Tag:</th><td>{$item/tag/text()}</td></tr>
</tbody>
</table> }
Copyright 2008 Dan McCreary & Associates

10. Copyright 2008 Dan McCreary & Associates
edit.xq Architecture
Generates an XHTML XForms on the fly
Works for both new items and updates to items
Calls save-new.xq if it has a new item
Calls update.xq if it is updating an existing item
Copyright 2008 Dan McCreary & Associates

11. Copyright 2008 Dan McCreary & Associates
edit.xq
Copyright 2008 Dan McCreary & Associates

12. Copyright 2008 Dan McCreary & Associates
Excerpts from edit.xq
let $new := request:get-parameter('new', '')
let $id := request:get-parameter('id', '') …
let $file := if ($new)
then ('new-instance.xml')
else ( concat( $server-port, '/exist/rest', $collection, '/', $id, '.xml'))
<xf:submission id="save" method="post" action="{if ($new='true') then ('save-new.xq') else ('update.xq')}" instance="my-task" replace="all"/>
Copyright 2008 Dan McCreary & Associates

13. Copyright 2008 Dan McCreary & Associates
New Instance
<item>
<id/>
<name/>
<description/>
<category/>
<status/>
<tag/>
</item>
Contains initial values of default form. Booleans must have true/false set.
Copyright 2008 Dan McCreary & Associates

14. XForms Controls for edit.xq
<xf:input ref="name">
<xf:label>Name:</xf:label>
</xf:input>
<xf:textarea ref="description" class="description">
<xf:label>Question:</xf:label>
</xf:textarea>
<xf:select1 ref="category" class="category">
<xf:label>Category:</xf:label>
<xf:item>
<xf:label>Small</xf:label>
<xf:value>small</xf:value>
</xf:item>
<xf:label>Medium</xf:label>
<xf:value>medium</xf:value>
<xf:label>Large</xf:label>
<xf:value>large</xf:value>
</xf:select1>
Copyright 2008 Dan McCreary & Associates

15. Copyright 2008 Dan McCreary & Associates
save-new.xq …
(: this is gets the data from the XForms submission :)
let $item := request:get-data()
(: this creates the new file with a still-empty id element :)
let $store := xmldb:store($data-collection, $file, $item)
(: this adds the correct ID to the new document we just saved :)
let $update-id := update replace doc(concat($data-collection, '/', $file))/item/id with <id>{$id}</id>
(: this updates the next-id.xml file :)
let $new-next-id := update replace doc($next-id-file-path)/data/next-id/text() with ($id + 1)
return
<html>…
Copyright 2008 Dan McCreary & Associates

16. Copyright 2008 Dan McCreary & Associates
update.xq …
(: Get the data from the XForms POST submission :)
let $item := request:get-data()
(: this saves the new file and overwrites the old one :)
let $store := xmldb:store($collection, $file, $item)
return
<html>
<head>
<title>Update Confirmation</title>
</head>
<body>
<a href="../index.xhtml">Item Home</a> > <a href="../views/list-items.xq">List all Items</a> > <a href="../views/view-item.xq?id={$id}">View Item</a>
<p>Item {$id} has been updated.</p>
</body>
</html>
Note that save and update do not take URL parameters. They get all their data from the POST.
Copyright 2008 Dan McCreary & Associates

17. Copyright 2008 Dan McCreary & Associates
delete-confirm.xq
xquery version "1.0";
let $id := request:get-parameter("id", "") …
return
<html>
<body>
<a href="../index.xhtml">Item Home</a> > <a href="../views/list-items.xq">List Items</a>
<h1>Are you sure you want to delete this Item?</h1>
<b>Name: </b>{doc($doc)/item/name/text()}<br/>
<b>Path: </b> {$doc}
<br/>
<a class="warn" href="delete.xq?id={$id}">Yes - Delete This Item?</a>
<a class="warn" href="../views/view-item.xq?id={$id}">Cancel (Back to View Item)</a>
</body>
</html>
Note that save and update do not take URL parameters. They get all their data from the POST.
Copyright 2008 Dan McCreary & Associates

18. Copyright 2008 Dan McCreary & Associates
delete.xq
let $collection := '/db/apps/manage-items/data'
(: this script takes the integer value of the id parameter passed via get :)
let $id := xs:integer(request:get-parameter('id', ''))
(: this logs you into the collection :)
let $login := xmldb:login($collection, ‘username', ‘password')
(: this constructs the filename from the id :)
let $file := concat($id, '.xml')
(: this REALLY deletes the file :)
let $store := xmldb:remove($collection, $file)
return
<html>
Note that save and update do not take URL parameters. They get all their data from the POST.
Copyright 2008 Dan McCreary & Associates

19. How CRUD Applications Work Together
search.xhtml
search.xq
index.xhtml
view-item.xq
save-new.xq
list-items.xq
edit.xq
optional
update.xq
delete-confirm.xq
delete.xq
Note: If you change a file name of an XQuery, make sure that everything that links to it is also updated
Copyright 2008 Dan McCreary & Associates

20. Copyright 2008 Dan McCreary & Associates
Next Steps
Create additional reports for users
Customized dashboards
Use status codes to filter data
Data quality reports
Customize Forms for specific users
Add role-based functions so each role has custom views and forms
Build custom searches for specific users
Copyright 2008 Dan McCreary & Associates

21. Copyright 2008 Dan McCreary & Associates
Thank You!
Please contact me for more information:
Native XML Databases
Metadata Management
Metadata Registries
Service Oriented Architectures
Business Intelligence and Data Warehouse
Semantic Web
Dan McCreary, President
Dan McCreary & Associates
Metadata Strategy Development
(952)
Copyright 2008 Dan McCreary & Associates