1) I am using the NewID() to generate the random numbers for one column in sql database table. Does it check for the uniqueness in the database table? This is how I am generating the random number and in the table the column's datatype is given as int.
ABS(CAST(CAST(NEWID() AS VARBINARY) AS INT))
2) On my WebPage, if user edits something, I want to keep track of old data and new data as well. So, What I am doing is , I am just inserting a new record in to the table. Is there any other best way to do this? Something like audit, Which will have everything in it, like what was changed and when was it changed?