24.3 Advanced Server Behaviors

In addition to the server behaviors described already, you'll find two other sets of behaviors that come in handy on dynamic Web pages.

You can also download many more third-party server behaviors from the Macromedia Exchange. Click the + button in the Server Behaviors panel and choose Get More Server Behaviors. Dreamweaver launches your Web browser and connects to the Dreamweaver Exchange site.

Not all extensions listed here work with Dreamweaver MX 2004. On the other hand, many of the server behaviors for Dreamweaver MX also work with MX 2004.

24.3.1 Recordset Paging

This set of five different behaviors lets you add links for jumping to different records in a recordset (straight to the last record, for example). In fact, Dreamweaver makes use of these same behaviors as part of its Recordset Navigation Bar object. You'll use these for moving through a long list of records, like a complete listing of products in a database.

To begin, add a recordset to a page. It should contain multiple records, since jumping to the next record when there's only one doesn't make much sense. The page could also contain a repeating region, so that several records appear.

You can add the recordset paging server behaviors from the Server Behaviors panel, or from the new recordset paging menu on the Application tab of the Insert Bar (see Figure 24-7).

Move to First Record adds a link that jumps to the first record in the recordset.

NOTE

In ColdFusion, ASP.NET, and PHP, you'll see the word Page instead of Record in this example and the following ones. For example, Move to First Page instead of Move to First Record.

Move to Previous Record adds a link that jumps to the record before the current record. If you use a repeating region, it jumps to the previous set of records. For example, say you create a repeating region that displays five records at a time. If the page currently displays records 6-10, clicking a link with this server behavior applied to it causes records 1-5 to appear.
Move to Next Record adds a link that jumps to the next record in the recordset. If you use a repeating region, it jumps to the next set of records.
Move to Last Record adds a link that goes to the last record in the recordset.
Move to Specific Record adds a link that goes to a single record based on information passed in the URL.

You can create your own recordset navigation controls using the recordset paging server behaviors.

Using any of the first four behaviors involves the same steps:

Create a recordset and add dynamic content to the page.
For example, you could create a list of all products your company sells. The recordset should contain at least enough records to span several pages. (You wouldn't use any of these behaviors if you display all of the records on a single page.)
Click the page where you wish to insert the link.
You can also select an item on the page—text or a graphic—that you'd like to turn into a link.
From the Server Behaviors panel, click the + button. Select Recordset Paging, and then choose a behavior from the submenu.
The window for the particular server behavior appears (see Figure 24-8).
Choose a recordset from the Recordset menu.
This is the recordset the behavior will move through.

The recordset paging behaviors can add a new link, or add a link to text or an image you've selected on the page. You can also use the menu to select any link already on the page. That's usually not a good idea, however, since Dreamweaver will erase whatever link was previously applied.
Click OK.
Dreamweaver adds the server behavior to the page and adds its name to the Server Behaviors panel.

The Move to Specific Record behavior works a bit differently. It doesn't add a link to the page; it simply forces the page to display a particular record when the page is requested. It does this by looking for a URL parameter that specifies a particular record in the recordset. In general, this isn't a good approach, since it requires the database server to retrieve many records just to display a single item from the database, which is a waste of server resources. On a busy site, that could mean a slowdown. You're better off creating a detail page (Section 22.7), which simply retrieves one record from the database.

24.3.2 Show Region Server Behaviors

At times, you'll want to display different information on a page based on the results of a recordset. For example, if a visitor searches your site's database of products for a product you don't sell, the search results page should say something like, "Sorry, we don't carry alligator skin bicycle seats." But if someone searches for a product you do sell, then the page should present the relevant details for that product. The Web page displays different text depending upon whether the search item was in the recordset.

Dreamweaver provides three sets of server behaviors that let you display any selection of HTML based on the results of a recordset.

Show If Recordset Is Empty. If the recordset retrieves no records, this behavior will make the selected HTML appear in the browser window.
This behavior comes in handy for a search page. On the search results page, apply it to some text like "We're sorry your search retrieved no results," and you've got yourself a friendly solution for searches that turn up empty.
Show If Recordset Is Not Empty. If the recordset retrieves any records, this behavior will cause the selected HTML to appear in the browser window: a list of search results or details on a specific database record, for example.
Show If First Page. This server behavior, like the next three, works in conjunction with recordset paging behaviors. It makes the selected HTML appear when the page displays the first record of a recordset, which comes in handy when you want to let people step through several pages of records.
Show If Not First Page is the opposite of the previous one. If the page does not contain the first record in a recordset, then the selected HTML appears.
Dreamweaver makes use of this behavior in its Recordset Navigation Bar (see Section 22.4). In that case, if the page displays anything except the first item in a recordset, the First Item and Previous Page links appear. If the page does display the first item in a recordset, those links are hidden. (After all, you can't very well view the Previous Page if you're on Page 1.)
Show If Last Page functions just like the Show If First Page behavior, but for the last record in a recordset.
Show If Not Last Page functions just like the Show If Not First Page behavior, but for the last record in a recordset. Dreamweaver uses this behavior to hide or show the Next Page and Last Item links in the Recordset Navigation Bar (Section 22.4).

The Show Region server behaviors are available on both the Application tab of the Insert bar and the Server Behaviors panel.

You can use these behaviors to show any selected object on the page—a paragraph of text, an image, a table, and so on. Your page can contain any combinations of these behaviors, and you can use any behavior two or more times to display multiple areas of a page. For example, maybe you'd like two things to appear when the recordset successfully retrieves a record: a graphic in the page's sidebar and a message in the main area of the page. You'd apply a Show If Recordset Is Not Empty server behavior to both selections of HTML (the graphic and the message).

You'll often use these behaviors in pairs. For example, a search results page should include both the "Show If Recordset Empty" behavior to display a "no results" message, and a "Show If Recordset Not Empty" behavior to display the search results.

To apply any of these behaviors:

Create a dynamic page containing a recordset.
This could be search results page, or a master page that lists many records from the database.
Select the HTML you wish to show based on a recordset outcome.
For example, when applying a Show If Recordset Is Empty server behavior to a search result page, select the message that should appear if the search returns no results.
Open the Server Behaviors panel (WindowServer Behaviors). Click the + button, select Show Region, and choose one of the six behaviors from the submenu.
A window like Figure 24-10 appears. While the title of the window varies depending on which behavior you selected, each of the six behaviors has just this one option.

NOTE

The last four behaviors—Show If First Page, Show If Not First Page, Show If Last Page, and Show If Not Last Page—work only on pages that also have one of the recordset paging server behaviors applied.

Select the name of the recordset from the menu and click OK.
The recordset you select should be the one whose results you're interested in. For example, on a search results page, you'd select the recordset you created to perform the search.

Regardless of which of the Show Region server behaviors you apply, there's only one option to choose: the recordset whose results control the display of the region.

After applying one of these behaviors to a selection of HTML, a gray line appears around the selection, and a gray tab appears bearing the words "Show If." That's the area that will appear if the given recordset condition is met (for example, if the page is displaying the last record of the recordset).

To remove a Show Region server behavior, select its name in the Server Behaviors panel and click the - button (or press the Delete key). Doing so removes the gray tab and outline. Now the affected HTML will appear regardless of the recordset results.

NOTE

PHP note—An extension called PHP Show If Recordset Field Condition Is True (available for free on the Macromedia exchange) lets you display part of a page when a field from a recordset matches a certain condition. Suppose, for example, that you have a products database with a field that records whether a particular item is for sale. If the item is indeed for sale, then you can use this behavior to display a large "For Sale" graphic on the product's detail page.

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