Conditional Trigger

Hello,

I have a situation where I'd like to fire a trigger only when certain conditions are met for data that's inserted into it's parent table.

Here is what I'm working with -

The PropertyScenarioIndex table currently contains this data:
PropertyID ScenarioType ScenarioID
1732 financing 1
1732 financing 2
1732 financing 3
1732 income_expense 1
1732 income_expense 2

The PropertyScenarioIndex table has a trigger on it (the one that needs to be made conditional) whose purpose is to automatically insert rows into another table called IncomeAndExpenseData to make entries easier for the user in that table. Here is the trigger:




Code Snippet

CREATE TRIGGER addstandardIncomeAndExpenserows ON PropertyScenarioIndex
AFTER INSERT
AS
insert into IncomeAndExpenseData
select
properytID = t1.propertyID,
scenarioID = t1.scenarioID,
itemID = t2.itemID,
itemvalue = null,
monthitemvalue = null
from PropertyScenarioIndex t1
cross join IncomeAndExpenseCodes t2
where
t1.propertyID+t1.scenarioID in (select propertyID+scenarioID from Inserted)
and t2.standarditem = 1
With the trigger as it is above, when the user tries to enter the following into PropertyScenarioIndex:
PropertyID ScenarioType ScenarioID
1732 income_expense 3
an error message appears that says Violation of PRIMARY KEY constraint 'PK_IncomeExpenseData'. Cannot insert duplicate key in object 'IncomeExpenseData'.

Is there some way to include code in the trigger that makes it fire only when the data inserted into the PropertyScenarioIndex table has a ScenarioType of 'income_expense'?

Note: in the where statement of the trigger above I have also tried this:




Code Snippet

where
t1.propertyID+t1.scenarioID in (select propertyID+scenarioID from Inserted where scenariotype = 'income_expense')but got the same error message as noted above.

Thanks, Knot

P.S. The primary keys in the PropertyScenarioIndex table are PropertyID, ScenarioType, ScenarioID and the primary keys in the IncomeExpenseData table are called PropertyID, ScenarioID, ItemID.