SQL Query - solving duplicate data - sql

Question

Here are the 2 tables I am using currently with some example data:
Finances
FinanceID Variation Total
1 0 £1,000.00
5 1 £250.00
24 2 £500.00
A Project can contain multiple Finances, Variation 0 is the Original Order, and each Finance line here after is 1 greater than the previous.
Application
ApplicationID ApplicationNumber PercentageComplete Value
5 1 20% £200.00
17 2 50% £300.00
35 3 75% £250.00
91 4 90% £150.00
The Application table above references the Original Finance Line, NOT the Variations
and here is an example of my problem which I will explain in more detail after:
Application 5 PercentageComplete Value
Contains no Variations
Application 17 PercentageComplete Value
Contains Variation 1 40% £100.00
Application 35 PercentageComplete Value
Contains Variation 1 100% £150.00
Contains Variation 2 25% £125.00
Application 91 PercentageComplete Value
Contains Variation 1 100% £0.00
Contains Variation 2 60% £175.00
An Application can contain multiple Variations
Once an Application contains a Variation, it needs to be automatically added to the next Application that is created.
So using the above example, the user would manually add Variation 1 to Application 17, enter its percentage complete, and the the value would be calculated automatically
MY PROBLEM:
Now for Application 35, I want the variation line from the previous Application added to this one AUTOMATICALLY, however when the infomation is edited (now at 100%) i do not want this to affect Application 17.
is my only option to keep duplicating the data for each Variation Line or is there a more efficient method someone could help me with? I have tried writing a Query to do this also, which was a lot more difficult than i anticipated so if this is the only method, some pointers or an example would be great help.
For the Query, I created this table to try it:
VariationLine ApplicationID VariationID PreviousPercentage NewPercentage Value
1 17 1 0% 40% £100.00
2 35 1 40% 100% £150.00
3 35 2 0% 25% £125.00
4 91 1 100% 100% £0.00
5 91 2 25% 60% £175.00
If I was to add a 5th Application, then I would need to insert the 2 previous VariationLines for the new Project (4 and 5)
Short Version of my problem:
I have an 4 Application's... The 1st has no Variations and just its own cost. For the 2nd Application the user manually adds Variation 1 with a percentage complete of 40% (£100.00)... when the user creates the 3rd Application, I would like SQL Server to automatically add the 1st Variation to this Project, as a new Variation line so that i can ammend the percentage complete and not affect the previous Application
Entity Relationship Diagram

Answer 1

I have created a view to first determine the the previous VariationLines based upon a changedate column, and when a new Application is added, then this view below would select all of the Applications Variations based on the previous Application. If the Application was a 1st, then nothing is added at first, a user has the option to add in Variations to the Application at any point in time.
CREATE VIEW NextApplicationVariations AS
SELECT variationid,
(SELECT TOP (1) applicationid
FROM dbo.applications
ORDER BY changedate DESC) AS ApplicationID,
(SELECT TOP (1) applicationnumber
FROM dbo.applications
ORDER BY changedate DESC) AS ApplicationCounter,
variationpercentage,
0 AS VariationValue,
variationpercentage AS PreviousPercentage,
projectreference,
totalvariationvalue,
0 AS VariationRetention
FROM dbo.variationline
WHERE ( projectreference = (SELECT TOP (1) projectreference
FROM dbo.projectcosts
ORDER BY changedate DESC) )
AND ( applicationcounter = (SELECT TOP (1) applicationnumber
FROM dbo.applications
ORDER BY changedate DESC) - 1 )
Now all thats left to do is insert the new lines based upon this view, and now this query is ran in a view, I can use the NOT EXISTS in the query to determine whether the latest Application has had its VariationLines added automatically
--INSERT PREVIOUS VARIATIONS INTO NEW APPLICATIONS
INSERT INTO variationline
(variationid,
applicationid,
applicationcounter,
variationpercentage,
variationvalue,
previouspercentage,
projectreference,
totalvariationvalue,
variationretention)
SELECT nextvariationline.variationid,
nextvariationline.applicationid,
nextvariationline.applicationcounter,
nextvariationline.variationpercentage,
nextvariationline.variationvalue,
nextvariationline.previouspercentage,
nextvariationline.projectreference,
nextvariationline.totalvariationvalue,
nextvariationline.variationretention
FROM nextvariationline
WHERE NOT EXISTS (SELECT *
FROM variationline
WHERE nextvariationline.applicationid =
variationline.applicationid)