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Practical Examples: Applying These Techniques in Your Application
The following are several practical applications of the advanced techniques learned in this chapter.NOTE
 | The examples shown in this section are included in the CHAP11EX.MDB database on the sample code CD-ROM. |
Archive Payments
After a while, you might need to archive some of the data in the tblPayment table. Two queries archive the payment data. The first, called qappAppendToPaymentArchive, is an Append query that sends all data in a specified date range to an archive table called tblPaymentsArchive (see Figure 11.44). The second query, called qdelRemoveFromPayments, is a Delete query that deletes all the data archived from the tblPayments table (see Figure 11.45). The archiving is run from a form called frmArchivePayments, where the date range can be specified by the user at runtime (see Figure 11.46).
Figure 11.44. The Append query qappAppendToPaymentArchive.
Figure 11.45. The Delete query qdelRemoveFromPayments.
Figure 11.46. The form that supplies criteria for the archive process.
Show All Payments
At times, you might want to combine data from both tables. To do this, you'll need to create a Union query that joins tblPayments to tblPaymentsArchive. The query's design is shown in Figure 11.47.
Figure 11.47. Using a Union query to join tblPayments to tblPaymentsArchive.
Create State Table
Because you'll regularly be looking up the states and provinces, you want to build a unique list of all the states and provinces in which your clients are currently located. The query needed to do this is shown in Figure 11.48. The query uses the tblClients table to come up with all the unique values for the StateProvince field. The query is a Make Table query that takes the unique list of values and outputs it to a tblStateProvince table.
Figure 11.48. A Make Table query that creates a tblStateProvince table.
