The Data Warehouse Development Life Cycle
Oracle Data Warehouse Design
Creating An SQL Generating Front End
The examples in this section were
originally written for an IBM mainframe environment, using DB2 as
the database and IBM REXX as the language for the SQL generator. The
first end user screen, shown in Figure 4.15, allows a user to choose
a type of query. The end user is presented with a list of predefined
reports. In this fashion, end users may choose from a set of report
Figure 4.15 A screen to choose a report type.
After choosing the type of report
desired, the next screen appears. This screen allows the entry of
variance criteria (see Figure 4.16). The selected variance is used
in the WHERE clause of the SQL SELECT statement, and
this screen will be interrogated by the routine to generate the SQL.
Note that the warehouse allows queries that compare one specific
month with another specific month. This makes it very easy to
compare two periods of time.
Figure 4.16 A screen used to choose variance criteria.
Figure 4.16 shows a sample data
selection screen as it could be filled out by a user. The next
screen, shown in Figure 4.17, allows end users to choose specific
data attributes to limit a query. The end user may select a specific
store, all stores in a city, or all stores within a standard
metropolitan statistical area (SMSA). This screen also allows end
users to constrain a query by a range of ZIP codes or a number of
transactions during a chosen period. Each constraint is added to the
WHERE clause with an AND condition.
Figure 4.17 Additional selection criteria.