c# - DELETE fails with "foreign key constraint failed" even though ON DELETE CASCADE is specified -

i'm working on c# project , i'm using system.data.sqlite. have 3(relevent) tables created with

create table students(     _id integer primary key,     fname text not null,     lname text not null,     st_number integer not null unique,     level integer not null,     class integer, foreign key (class) references classes(_id) on delete cascade on update cascade, foreign key (level) references levels(_id) on delete cascade on update cascade)  create table payments(     _id integer primary key,     student integer not null,     amount integer not null,     recieve_date text not null,     type text not null, foreign key(student) references students(st_number) on update cascade on delete cascade)  create table signups(     _id integer primary key,     student integer not null,     service integer not null, foreign key(student) references students(st_number) on update cascade on delete cascade, foreign key(service) references services(_id) on update cascade on delete cascade) 

now when try delete record students table fk violation error while i'm expecting delete connected entries payments , signups table.

it might connected way turn on fk support in sqlite. turn on in connection string

@"data source=" + dbpath + ";version=3;foreign_keys = 1;" 

sorry long create statements. appreciated.

@"data source=" + dbpath + ";version=3;foreign_keys = 1;" 

looks typo, , should changed to:

@"data source=" + dbpath + ";version=3;foreign keys = 1;" 

i changed _ blank space.