I have a coulumn named Status which can have only three values:
1. Available (Default)
How can I add this functionality while creating the table? i.e. while creating the table itself how can i specify that the column can hold only these 3 values and populate all rows with the default value?
Pretty much as mentioned the constraints are the way to go. You can use a lookup table to easily do this as well. So you have your lkp_Status table, just with those 3 values. And you can create a primary foreign key constraint as well. This way in the future if a value is added and there needs to be 4 values you can just add the value in the lookup table and the primary foreign key relationship remains the same. It doesn't need to change.