Answers for "alter table to allow nulls to be inserted sql"

set column to not null mysql

ALTER TABLE Person MODIFY P_Id INT(11) NOT NULL;

alter column to not null with default value sql server

ALTER TABLE SomeTable
        ADD SomeCol Bit NULL --Or NOT NULL.
 CONSTRAINT D_SomeTable_SomeCol --When Omitted a Default-Constraint Name is autogenerated.
    DEFAULT (0)--Optional Default-Constraint.
WITH VALUES --Add if Column is Nullable and you want the Default Value for Existing Records.