SQL Server 2019

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CREATE TABLE dbo.Something
(
    Id bigint,
    OtherId bigint,
    
    CONSTRAINT PK_Something PRIMARY KEY (Id)
);
SELECT [name], is_nullable
FROM sys.columns c 
WHERE 
    c.[object_id] = OBJECT_ID('dbo.Something');


name
is_nullable


Id
False

OtherId
True


ALTER TABLE dbo.Something
DROP CONSTRAINT PK_Something;
SELECT [name], is_nullable
FROM sys.columns c 
WHERE 
    c.[object_id] = OBJECT_ID('dbo.Something');


name
is_nullable


Id
False

OtherId
True