Adding a relationship constraint to an existing or new column in MS SQL

existing.sql

ALTER TABLE [dbo].[MyTable]
ADD CONSTRAINT FK_MyTable_OtherTable FOREIGN KEY (OType)
REFERENCES [dbo].[OtherTable] (Ident)
ON DELETE CASCADE
ON UPDATE CASCADE

newTable.sql

CREATE TABLE [dbo].[MyTable] (Ident int NOT NULL, Name nvarchar(50), OType int 
CONSTRAINT PK_MyTable PRIMARY KEY NONCLUSTERED (Ident), 
CONSTRAINT FK_MyTable_OtherTable FOREIGN KEY (OType) 
    REFERENCES [dbo].[OtherTable] (Ident) 
    ON DELETE CASCADE
    ON UPDATE CASCADE
)