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Chapter 10 Displaying XML Documents Using Data Binding 313 10 Data Binding <PAGES>256</PAGES> <PRICE>$4.95</PRICE> </BOOK> <BOOK> <TITLE>Roughing It</TITLE> <AUTHOR>Mark Twain</AUTHOR> <BINDING>mass market paperback</BINDING> <PAGES>324</PAGES> <PRICE>$5.25</PRICE> </BOOK> <BOOK> <TITLE>The Scarlet Letter</TITLE> <AUTHOR>Nathaniel Hawthorne</AUTHOR> <BINDING>trade paperback</BINDING> <PAGES>253</PAGES> <PRICE>$4.25</PRICE> </BOOK> <BOOK> <TITLE>The Turn of the Screw</TITLE> <AUTHOR>Henry James</AUTHOR> <BINDING>trade paperback</BINDING> <PAGES>384</PAGES> <PRICE>$3.35</PRICE> </BOOK> </INVENTORY> Listing 10-3. Inventory Big Table.htm <! File Name: Inventory Big Table.htm > <HTML> <HEAD> <TITLE>Book Inventory</TITLE> </HEAD> <BODY> <XML ID="dsoInventory" SRC="Inventory Big.xml"></XML> <H2>Book Inventory</H2> 314 XML Step by Step <BUTTON ONCLICK="InventoryTable.firstPage()"> |< First Page </BUTTON>    <BUTTON ONCLICK="InventoryTable.previousPage()"> < Previous Page </BUTTON>    <BUTTON ONCLICK="InventoryTable.nextPage()"> Next Page > </BUTTON>    <BUTTON ONCLICK="InventoryTable.lastPage()"> Last Page >| </BUTTON> <P> <TABLE ID="InventoryTable" DATASRC="#dsoInventory" DATAPAGESIZE="5" BORDER="1" CELLPADDING="5" WIDTH="100%"> <THEAD> <TH>Title</TH> <TH>Author</TH> <TH>Binding</TH> <TH>Pages</TH> <TH>Price</TH> </THEAD> <TR ALIGN="center"> <TD><SPAN DATAFLD="TITLE" STYLE="font-style:italic"></SPAN></TD> <TD><SPAN DATAFLD="AUTHOR"></SPAN></TD> <TD><SPAN DATAFLD="BINDING"></SPAN></TD> <TD><SPAN DATAFLD="PAGES"></SPAN></TD> <TD><SPAN DATAFLD="PRICE"></SPAN></TD> </TR> </TABLE> </BODY> </HTML> Listing 10-4. Chapter 10 Displaying XML Documents Using Data Binding 315 10 Data Binding Using a Nested Table to Display a Hierarchical Record Set In the previous sections, you learned how to use a single table to display an XML document structured as a simple record set. (A simple record set is described at the beginning of the earlier section “Using a Single HTML Table to Display a Simple Record Set.”) You’ll now learn how to use nested tables to display an XML document whose elements are structured in a hierarchical record set. In a hierarchical record set, each record can contain, in addition to an optional fixed set of fields, zero or more nested records (see the following Note). Listing 10-5 shows an example of an XML document structured as a hierarchical record set. (You’ll find a copy of this listing on the companion CD under the filename Inventory Hierarchy.xml.) In this document, the root element (INVEN- TORY) contains a series of CATEGORY records. Each CATEGORY record be- gins with a single CATNAME field, which contains character data only, and then has two or more nested BOOK records. Each nested BOOK record has ex- actly five fields (TITLE, AUTHOR, BINDING, PAGES, and PRICE). note As a general rule, if an element contains one or more children (or attributes, as explained later), or if the same element type occurs more than once within a given parent, the DSO interprets the element or elements as a record (or set of records), rather than as a field (or set of fields). In Inventory Hierarchy.xml, the CATEGORY and BOOK elements meet both of these criteria, so they are clearly considered to be records. (The CATNAME, TITLE, AUTHOR, BINDING, PAGES, and PRICE elements meet neither criteria, so they are considered to be fields.) A TABLE element is the only type of HTML element that you can bind to an XML record. Inventory Hierarchy.xml <?xml version="1.0"?> <! File Name: Inventory Hierarchy.xml > <INVENTORY> <CATEGORY> <CATNAME>Middle Ages</CATNAME> <BOOK> <TITLE>The Canterbury Tales</TITLE> <AUTHOR>Geoffrey Chaucer</AUTHOR> <BINDING>hardcover</BINDING> <PAGES>692</PAGES> Chapter 10 Displaying XML Documents Using Data Binding 317 10 Data Binding </BOOK> <BOOK> <TITLE>The History of Tom Jones: A Foundling</TITLE> <AUTHOR>Henry Fielding</AUTHOR> <BINDING>hardcover</BINDING> <PAGES>438</PAGES> <PRICE>$16.95</PRICE> </BOOK> <BOOK> <TITLE>Love in Excess</TITLE> <AUTHOR>Eliza Haywood</AUTHOR> <BINDING>trade paperback</BINDING> <PAGES>429</PAGES> <PRICE>$12.95</PRICE> </BOOK> <BOOK> <TITLE>Tristram Shandy</TITLE> <AUTHOR>Laurence Sterne</AUTHOR> <BINDING>hardcover</BINDING> <PAGES>322</PAGES> <PRICE>$9.49</PRICE> </BOOK> </CATEGORY> <CATEGORY> <CATNAME>19th Century</CATNAME> <BOOK> <TITLE>Dracula</TITLE> <AUTHOR>Bram Stoker</AUTHOR> <BINDING>hardcover</BINDING> <PAGES>395</PAGES> <PRICE>$17.95</PRICE> </BOOK> <BOOK> <TITLE>Great Expectations</TITLE> <AUTHOR>Charles Dickens</AUTHOR> <BINDING>mass market paperback</BINDING> <PAGES>639</PAGES> <PRICE>$6.95</PRICE> </BOOK> <BOOK> <TITLE>Percival Keene</TITLE> <AUTHOR>Frederick Marryat</AUTHOR> 318 XML Step by Step <BINDING>trade paperback</BINDING> <PAGES>425</PAGES> <PRICE>$12.89</PRICE> </BOOK> <BOOK> <TITLE>Treasure Island</TITLE> <AUTHOR>Robert Louis Stevenson</AUTHOR> <BINDING>trade paperback</BINDING> <PAGES>283</PAGES> <PRICE>$11.85</PRICE> </BOOK> <BOOK> <TITLE>Wuthering Heights</TITLE> <AUTHOR>Emily Bronte</AUTHOR> <BINDING>hardcover</BINDING> <PAGES>424</PAGES> <PRICE>$12.95</PRICE> </BOOK> </CATEGORY> </INVENTORY> Listing 10-5. Listing 10-6 contains an HTML page that uses a nested table to display the hierarchical record structure of the XML document in Listing 10-5. (You’ll find a copy of Listing 10-6 on the companion CD under the filename Inventory Hierarchy.htm.) Inventory Hierarchy.htm <! File Name: Inventory Hierarchy.htm > <HTML> <HEAD> <TITLE>Inventory of Classic English Literature</TITLE> </HEAD> <BODY> <XML ID="dsoInventory" SRC="Inventory Hierarchy.xml"></XML> <TABLE DATASRC="#dsoInventory" BORDER="1"> <THEAD> <TH>Classic English Literature</TH> Chapter 10 Displaying XML Documents Using Data Binding 319 10 Data Binding </THEAD> <TR> <TD><SPAN DATAFLD="CATNAME"></SPAN></TD> </TR> <TR> <TD> <TABLE DATASRC="#dsoInventory" DATAFLD="BOOK" BORDER="0" CELLSPACING="10"> <THEAD> <TH WIDTH="25%">Title</TH> <TH WIDTH="25%">Author</TH> <TH WIDTH="25%">Binding</TH> <TH WIDTH="10%">Pages</TH> <TH WIDTH="15%">Price</TH> </THEAD> <TR ALIGN="CENTER"> <TD WIDTH="25%"> <SPAN DATAFLD="TITLE" STYLE="font-style:italic"></SPAN> </TD> <TD WIDTH="25%"> <SPAN DATAFLD="AUTHOR"></SPAN> </TD> <TD WIDTH="25%"> <SPAN DATAFLD="BINDING"></SPAN> </TD> <TD WIDTH="10%"> <SPAN DATAFLD="PAGES"></SPAN> </TD> <TD WIDTH="15%"> <SPAN DATAFLD="PRICE"></SPAN> </TD> </TR> </TABLE> </TD> </TR> </TABLE> </BODY> </HTML> Listing 10-6. 320 XML Step by Step In Listing 10-6, the outer table is bound to the XML document, as you can see in its start-tag: <TABLE DATASRC=”#dsoInventory” BORDER=”1"> The outer table includes a heading (a THEAD element displaying “Classic En- glish Literature”), plus two table rows (two TR elements). The browser repeats the two rows for each top-level record (that is, for each CATEGORY record). The first row displays the CATNAME field. So far, everything works just like the example table that displays a simple record set, given previously in Listing 10-2. However, the second row, rather than displaying fields, contains a nested table that displays the contents of each nested BOOK record within the current category. Here’s the markup for only the nested table: <TABLE DATASRC="#dsoInventory" DATAFLD="BOOK" BORDER="0" CELLSPACING="10"> <THEAD> <TH WIDTH="25%">Title</TH> <TH WIDTH="25%">Author</TH> <TH WIDTH="25%">Binding</TH> <TH WIDTH="10%">Pages</TH> <TH WIDTH="15%">Price</TH> </THEAD> <TR ALIGN="CENTER"> <TD WIDTH="25%"> <SPAN DATAFLD="TITLE" STYLE="font-style:italic"></SPAN> </TD> <TD WIDTH="25%"> <SPAN DATAFLD="AUTHOR"></SPAN> </TD> <TD WIDTH="25%"> <SPAN DATAFLD="BINDING"></SPAN> </TD> <TD WIDTH="10%"> <SPAN DATAFLD="PAGES"></SPAN> </TD> <TD WIDTH="15%"> <SPAN DATAFLD="PRICE"></SPAN> </TD> </TR> </TABLE> 322 XML Step by Step In this case, you could use an additional nested table to display all the authors for each BOOK element, employing the same basic techniques shown for a singly nested table. (Although in the example XML document each book has only a single author, an additional nested table would display multiple authors, if present. For the additional nested table, you would set DATAFLD equal to "AUTHOR".) Using Single-Record Data Binding Single-record data binding refers to binding an HTML element that isn’t a table and isn’t included in a bound table. The HTML element—for example, a SPAN, BUTTON, or LABEL element—is bound to an individual XML field (not to a record). The HTML element then automatically displays the content of the XML field to which you bind it. For example, the following HTML SPAN element is bound to the TITLE field in the XML document that’s accessed through the dsoInventory data island: <SPAN DATASRC=”#dsoInventory” DATAFLD=”TITLE”></SPAN> To use single-record data binding as described in this section, the XML document must be organized as a simple record set. I gave a description of a simple record set at the beginning of the section “Using a Single HTML Table to Dis- play a Simple Record Set” on page 302. Because the HTML element doesn’t have multiple parts like a table, however, it can display the field’s value for only one record at a time. For example, if you wanted to display the book information in the Inventory Big.xml document (given in Listing 10-3), you could bind a SPAN element to each of the fields of a BOOK record, as in the following HTML page: <HTML> <HEAD> <TITLE>Book Description</TITLE> </HEAD> <BODY> <XML ID="dsoInventory" SRC="Inventory Big.xml"></XML> <H2>Book Description</H2> <SPAN STYLE="font-style:italic">Title: </SPAN> <SPAN STYLE="font-weight:bold" DATASRC="#dsoInventory" DATAFLD="TITLE"></SPAN> <BR> Chapter 10 Displaying XML Documents Using Data Binding 323 10 Data Binding <SPAN STYLE="font-style:italic">Author: </SPAN> <SPAN DATASRC="#dsoInventory" DATAFLD="AUTHOR"></SPAN> <BR> <SPAN STYLE="font-style:italic">Binding type: </SPAN> <SPAN DATASRC="#dsoInventory" DATAFLD="BINDING"></SPAN> <BR> <SPAN STYLE="font-style:italic">Number of pages: </SPAN> <SPAN DATASRC="#dsoInventory" DATAFLD="PAGES"></SPAN> <BR> <SPAN STYLE="font-style:italic">Price: </SPAN> <SPAN DATASRC="#dsoInventory" DATAFLD="PRICE"></SPAN> </BODY> </HTML> This page, however, would display only the first BOOK record in the XML document, as shown here: To circumvent this limitation, you need to use the technique for navigating through records described in the next section. Navigating Through the Records With single-record data binding, the bound HTML elements can display only one record at a time. The record that they display is known as the current record. (Hence, an alternative term for single-record data binding is current- record binding.) Initially, the current record is the first (or only) record in the document. 324 XML Step by Step The DSO associated with the XML document provides a set of methods that you can call to navigate through the records. These methods belong to the recordset member object of the DSO, and are listed in the following table. Note that the example calls in the last column assume that the HTML page contains an XML data island with the ID dsoInventory. DSO recordset Changes the Example call method current record to moveFirst The first record in dsoInventory.recordset.moveFirst() the document movePrevious The previous record dsoInventory.recordset.movePrevious() moveNext The next record dsoInventory.recordset.moveNext() moveLast The last record in dsoInventory.recordset.moveLast() the document move The record with the dsoInventory.recordset.move(5) specified number (Moves to the sixth record. Records are numbered starting with zero.) note The recordset member object of the DSO conforms to a standard data access technology that Microsoft calls ActiveX Data Objects (ADO). You can use the general-purpose ADO recordset object with a variety of different data sources, in addition to the XML DSO described in this chapter. For general information on ADO and the ADO recordset object, see the topic “Microsoft ActiveX Data Objects (ADO)” in the MSDN Library on the Web at http://msdn.microsoft.com/library/. See also Microsoft’s home page for information on ADO at http://www.microsoft.com/data/ado/. You can call any of these methods from a script that you write (as discussed later in the chapter). The easiest way to call one of them, however, is by assigning the method to the ONCLICK attribute of a BUTTON element, as shown here: <BUTTON ONCLICK=”dsoInventory.recordset.moveFirst()”> First Record </BUTTON> This element creates a push button that displays the text “First Record.” When the user clicks the button, the method assigned to the ONCLICK attribute, dsoInventory.recordset.moveFirst, gets called. [...]...326 XML Step by Step 2 Use your text editor’s Save command to save the page on your hard disk, assigning it the filename Inventory Single.htm Make sure that a copy of the Inventory Big .xml file is in the same folder in which you save Inventory Single.htm Inventory Single.htm Book Inventory Book Inventory < /XML> Book Inventory Cover Title Author Binding Pages Price... double-click the name of the file, Inventory Single.htm, that you saved in the previous step: 10 Internet Explorer will open the page and display it, as shown here: Data Binding 3 Notice that initially, until the user starts clicking the buttons, Internet Explorer displays only the first record in the document Chapter 10 Displaying XML Documents Using Data Binding Purpose of element FRAME Contains an src individual... which you save Inventory Single.htm Inventory Single.htm Book Inventory < /XML> Book Description Title: Author:... DATASRC="#dsoInventory" DATAFLD="PRICE"> |< First < Back . Inventory</TITLE> </HEAD> <BODY> < ;XML ID="dsoInventory" SRC="Inventory Big .xml& quot;>< /XML& gt; <H2>Book Inventory</H2> 314 XML Step by Step <BUTTON ONCLICK="InventoryTable.firstPage()"> . Yes control of the selected list item continued 330 XML Step by Step Render HTML Update Bound property contained bound HTML Purpose (or properties) in XML XML element of element of the element field?. Initially, the current record is the first (or only) record in the document. 324 XML Step by Step The DSO associated with the XML document provides a set of methods that you can call to navigate through

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