> #### Using cron-based scheduling

> You can now set up more complex scheduling by incorporating cron expressions in your job schedules. You can still specify that a job execute at a repeating calendar interval, such as every sixty minutes or once each day, for example. With cron-based scheduling, you can be even more specific about when you want a job to run, according to a business period interval: on the last Friday of the month, or every ten minutes from 4 PM to 6 PM daily, for example.

> If you choose to use a cron expression in scheduling a job, you select it as the Repeat interval, as shown in Figure 8–4.

> Figure 8–4: Selecting Cron expression as the Repeat interval

> You can include from one to five cron expressions (separated by semi-colons) in the Cron expression field in a job schedule. Each cron expression consists of five fields; each field describes a different part of the scheduling definition:

> - Minutes.
> - Hours.
> - Day of the month.
> - Month.
> - Day of the week.

> For example, you might use a cron expression as shown in Figure 8–5.

> Figure 8–5: Sample cron expression

> In this example, you specify that a job should be run at 8:15 AM every weekday of every month.

> If you also want the job to run once every Saturday and Sunday, but at a different time from when it runs each weekday, you can use two cron expressions, as shown in Figure 8–6.

> Figure 8–6: Sample of two cron expressions

> In this case, the job will still run at 8:15 AM each weekday of every month; the job will also run at 7:30 PM every Saturday and Sunday of every month.

> For more details about using cron expressions, click the Cron expression field Help button.

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