Our database is SQL Server 2008 R2. We have some tables that have some varchar(500) columns that I want to switch to datetime2 or bigint. I can guarantee all the data in the columns to be switched are valid for the proper type. The column changes do affect indexes, but not keys.
While discussing with colleagues, we have come to two ways to approach the problem. Both these would be done through T-Sql scripts.
- Create a temp table via select into, drop the old table and recreate the table with the proper datatypes. Recreate the indexes.
- Alter the current table/data types via
ALTER TABLE x ALTER COLUMN Y datetime2and then rebuild or recreate the indexes.
Because I am confident the data will convert cleanly, I am leaning towards #2. My colleague and a DBA friend prefer #1 but my colleague can't remember why they trained him that way. The DBA friend is on vacation so I didn't ask him why.
Can someone provide insight on which option they think is better and why? Ultimately it is my decision and I am wondering why #1 would be preferred over #2?