Adding an identity to an existing column

Question

I need to change the primary key of a table to an identity column, and there\'s already a number of rows in table.

I\'ve got a script to clean up the IDs to ensure

Answer 1

Consider to use SEQUENCE instead of IDENTITY.

IN sql server 2014 (I don't know about lower versions) you can do this simply, using sequence.

CREATE SEQUENCE  sequence_name START WITH here_higher_number_than_max_existed_value_in_column INCREMENT BY 1;

ALTER TABLE table_name ADD CONSTRAINT constraint_name DEFAULT NEXT VALUE FOR sequence_name FOR column_name

From here: Sequence as default value for a column