如何为列添加默认值？

Question

I want to add the column Season ID to the Team table with the default referencing the None value in the Season table (I don't want to say default = 'None', rather the SeasonID of the row that has 'None' as the Season Year), place a foreign key constraint on that column. Finally I need to add the Fall 2012 foreign key value into the Season ID column.

Here is my team table

teamID      teamName
----------- ---------------
100         No Winner      
101         Purple Pilots  
102         Red Devils     
103         Silver Lions   
104         Blue Jackets   
105         Green Hornets  
106         Gold Dragons   

Here is my Season table

SeasonID    SeasonName Year
----------- ---------- ----
100         None       0000
101         Fall       2012
102         Winter     2012

Here is what i tried to do but I can handle the referencing for another table as for default value

alter table team
add SeasonID int not null;

alter table team
add default 'None'
for SeasonID

alter table team
add constraint team_seasonid_fk foreign key (SeasonID)
references Season(SeasonID)
on update cascade
on delete cascade;


update team
set SeasonID = 101
where SeasonID = 'None';

How can I do it correctly?

Answer 1

Your column is of type int so you cant assign 'none' as it's default value. I suggest you to have a trigger on table and after insert find the default record from Season table and update the inserted record, or writing instead of insert trigger to do it at once.