Adding a new column
ALTER TABLE tbl_status ADD COLUMN status_default TEXT;
This will cause an error if the column already exists. To check if a column already exists first you can use:
which will return a table listing the columns of the table. However many people use the built in PRAGMA user_version) to store an incremental number which you increment as you update the database design (its starts from zero for a new database nless you specify it).