Transcript Week 7 March 8 • SQL: Chronological Sort, SUBSTRing, ROUND • Dynamic SQL: Host and Lexical Reference Variables • Overview: Drill-down, Roll-up Reports R.

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Week 7
March 8
• SQL: Chronological Sort, SUBSTRing, ROUND
• Dynamic SQL: Host and Lexical Reference
Variables
• Overview: Drill-down, Roll-up Reports
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Chronological sort
Month sequence in the calendar
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Order by the
month’s sequence
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Without Chronological Order
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Length
Beginning position
SUBSTR captures only parts of a string
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Without SUBSTR
Wasted space
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ROUND rounds a number to a
specified number of decimal places
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Number of
decimal places
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Without ROUND
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Order by Quarter
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Dynamic SQL
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• As opposed to static SQL, dynamic SQL allows the user to
specify parts of the query (i.e., column names, table
names, conditions, etc.) during runtime
• For example (static SQL):
SQL>
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select manufacturer_code, to_char(sales_month_97,'q'),
sum(sales_revenue_97), sum(sales_revenue_98)
from sales_97_98
where lower(manufacturer_code) = 'son'
group by manufacturer_code, to_char(sales_month_97,'q')
order by to_char(sales_month_97,'q');
The same columns, table and condition are used
R. Ching, Ph.D. • MIS Area • California State University, Sacramento
Dynamic SQL
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• With dynamic SQL, parts of the query can be substituted
by variable names
Lexical reference variable name
Host variable
Lexical reference variable designator
select manufacturer_code, &P_Time_interval,
sum(sales_revenue_97), sum(sales_revenue_98)
from sales_97_98
where lower(manufacturer_code) = :P_manufacturer_code
group by manufacturer_code, to_char(sales_month_97,'q')
order by &P_Time_interval;
Host variable designator
• During run time, the user will specify a value for
P_time_interval
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Creating a Lexical Reference Variable
• Create a lexical reference
variable under User
Parameters of the Data
Model (in the Object
Navigator)
Select

Create
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Create a User Parameter
Default name
Select the new parameter, right-mouse
click and select Property Palette
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Change the Properties
Change the name
Change the data type to character
Assign an initial value (optional)
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Insert the Lexical Reference Variables
(User Parameters)
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During Runtime...
Host variable
Lexical reference variables
(default values)
Host variable
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Drill-Down, Roll-up Reports
• A drill-down report is actually two or more
reports working together
• The top-level report is like a master record
– Launches a report that provides more details
about the data in its current record
• Generally, the detail report displays information
related to the master
– Provides details for a single record, a group
of records, or the report as a whole
– Master report "links" to the detail report by
passing parameters that control the
execution of the detail
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Master
Detail
Drill-Down Reports
Master Report
(Annual)
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Data Model 1
Parameter-list1
Drill-down Report
(Quarters)
Data Model 2
Parameter-list2
Drill-down Report
(Months)
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Data Model 2
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+
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=
Annual
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Quarters
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Months within a Quarter
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