Database Reference
In-Depth Information
focuses on sales volumes. In the future we may want this, but currently it is easy to
obtain but of little value to us. As such, dbo.RoySched is classified as not needed.
8.
Examine the dbo.Discounts table. We see that some stores seem to have discounts
tracked in the discounts table. This would seem to be something we would like to
include as well. And yet, let's say that we asked the company owner about how the
discounts were calculated. The company owner then informed us that not only are
discounts no longer tracked but the data in these fields are considered iffy at best. In
real life, it is common to discover something in the database that was once tracked
in the past but somehow got put away in the background and ignored. As time goes
by, the reason for this information is lost. This means that it is difficult to verify
that the data is truly valid, and even if the table would provide good information for
reports, it still should be classified as not needed.
9.
Examine the dbo.Pub_Info table. The publisher information table, dbo.Pub_Info,
would seem to be useful at first sight. On closer inspection, we see that it is probably
not useful to us. In real life, it is often the case that a table looks like it will be of use
at first glimpse, but upon further examination, it is not as pertinent as it first seemed.
In this case, we classify this table as nice to Have.
In the next section of this exercise, we take a look at the data in these tables to determine which columns
will be included.
Deciding Which Columns to Include from Sales
At this point, you have examined the tables and categorized them by priority. It is time to do a closer
inspection of the data in each of these tables. In SQl Server Management Studio, you can quickly look at the
contents of a table by right-clicking the table and selecting Select Top 1000 Rows from the context menu
(Figure
3-10
). We start with the sales table because it is central to our BI solution.
1.
Right-click the dbo.Sales table in the Object Explorer treeview and choose the Select
Top 1000 Rows menu item from the context menu. SQl Server Management Studio
will create and execute a SQl select statement for you and display the results in a
query window, as shown in Figure
3-10
.
