This assumes I’ve added a table called dbo.Order with a PK of OrderID.
However, I can do this in the CREATE TABLE statement, like shown below. I add a new section after a column with the CONSTRAINT keyword. Then I name the constraint, which is always a good practice. I can then add the FK keyword, the column and the references that connects this child column to the parent column.
This came about in SQL Server 2014, along with In-Memory OLTP and the ability to create indexes inline with the table create script. It’s a minor quality of life thing but I do enjoy it.