How do I create an automated calculated column?

Help me create a column, that shows the company’s budget. Let’s say we have three tables: Budget, Purchase, and Sale.

CREATE TABLE Budget (
ID int primary key identity(1,1) not null,
BudgetAmount float not null
);

CREATE TABLE PurchasingRawMaterials (
ID int primary key identity(1,1) not null,
RawMaterials int foreign key (Raw Materials) references RawMaterials (ID) not null,
Number int not null,
Price float not null,
Date date not null
);

CREATE TABLE ProductSales (
ID int primary key identity(1,1) not null,
Products int foreign key (Products) references FinishedProducts (ID) not null,
Number int not null,
Price float not null,
Date date not null
);

When we selling products, the budget increases, when buying raw materials, it decreases. That is, automatically when you add a value to these tables, the budget value immediately changes.

Answer

Use Inserted table inside the Trigger to find the recently inserted record and update the Price amount with the Budget Table.

CREATE TRIGGER TRG_PurchasingRawMaterials
ON PurchasingRawMaterials
AFTER INSERT
AS
BEGIN

UPDATE B
SET BudgetAmount=BudgetAmount-inserted.Price
FROM Budget B
INNER JOIN inserted On B.ID=inserted.RawMaterials

END
GO

CREATE TRIGGER TRG_ProductSales
ON ProductSales
AFTER INSERT
AS
BEGIN

UPDATE B
SET BudgetAmount=BudgetAmount+inserted.Price
FROM Budget B
INNER JOIN inserted On B.ID=inserted.Products

END