Microsoft SQL Server 2005 Reporting Services

A subscription is akin to setting up a job on the Report Server to deliver a report to a user at a specified point in time. This provides a nice alternative to actively going to the Report Server and running the report.

Parts of Subscriptions

Subscriptions all have some common components/requirements. In addition to the following, you must also have access to view the report, and have a role assignment that includes the task "Manage individual subscriptions" before you can subscribe to it. Common components /requirements of report subscriptions include the following:

• The report has to be able to run independently, that is, the data sources must use either stored credentials or no credentials.

• The report must have a configured delivery method. The built-in ones include email and file sharing.

• You must specify a rendering extension for the subscribed report.

• Some trigger or event is required to run the subscription. Usually, this is a scheduled event, based on either a custom or shared schedule.

• The parameter values for any parameter in a report must be specified or defaulted.

Uses of Subscriptions

Subscriptions have a number of possible uses that can be used to meet a number of requirements:

• Deliver reports to end users (the most common use of subscriptions).

• Save reports for offline viewing. This is usually done using PDF or web archive formats.

• Send long-running reports or large reports directly to disk.

• Preload the Report Server's cache.

Standard Versus Data-Driven Subscriptions

SSRS has two different kinds of subscription options. The first kind is called the standard subscriptions. Users can create and manage standard subscriptions for themselves . All the information for the subscription is static, which means that the information has to be specified when the subscription is created, and cannot be modified at runtime.

Data-driven subscriptions are similar to the standard subscription with one important difference. The data used for the subscription must come from a query. This makes data-driven subscriptions incredibly powerful. The list of recipients is derived via a query, which makes it ideal for recipient lists that can change frequently. Users can use data-driven subscriptions to create customized reports for recipients based on preferences of that recipient or that recipient's role within the organization. Even the delivery style and location can be customized. Data-driven subscriptions are usually kept in the domain of report administrators, and are typically not administered by end users.

Note

Data-driven subscriptions are only available in SQL Server 2005 Enterprise and Developer Editions.

Delivery Options

Reports are delivered using delivery extensions. Two delivery extensions come preloaded into SSRS and can be used by end users, although they cannot be configured. These are an email delivery extension and a file share delivery extension. Like many other parts of SSRS, end users can create their own delivery extensions if the existing ones are not sufficient. One kind of delivery extension an administrator can use that an end user cannot use is called the null delivery extension. As the name implies, it doesn't actually deliver a report anywhere . Instead, it is typically used to preload the Report Server cache or generate snapshots.

Subscription Processing

If you are familiar with SQL Server Notification Services, you might find the model that SSRS uses to process subscriptions familiar. SSRS responds to events. As events occur, SSRS matches these events to subscriptions that should be triggered by one or more of these events. When a subscription is triggered, the Report Server uses the information stored along with the subscription to process the report. When the report is done processing, the Report Server passes it along with the delivery information stored with the subscription to the appropriate delivery extension.

When processing a standard subscription, the Report Server's job is relatively simple. Because standard subscriptions contain only one report that does not vary by user, it simply processes the report and sends it on its merry way.

The processing of a data-driven subscription is considerably more complex. For a data-driven subscription, the number of reports, deliveries, and even parameters to pass to those reports depends on the data passed in. The Report Server must generate a report and deliver it based on every record returned from the data set generated by the query.