I have two tables, first with parts, second with orders. In orders i store IDPart and quantity of this part. I would like achieve that when inserting the IDPart and Quantity values ​​into the Orders, the trigger automatically fires up to calculate the price. Did someone can help to figure it out?

Sample:

CREATE TABLE Parts
(
    ID INT IDENTITY(1,1) PRIMARY KEY,               
    PartName NVARCHAR(70),
    Price NVARCHAR(70)
)

CREATE TABLE Orders
(
    ID INT IDENTITY(1,1) PRIMARY KEY,   
    IDPart INT REFERENCES Parts(ID),
    Quantity INT,
    Price DECIMAL(6,2)
)