SQLite3 不支持外键约束吗?

I have created 2 tables persons and orders using the following SQL script:

sqlite> create table Persons(
            P_Id int primary key,
            LastName varchar,
            FirstName varchar,
            Address varchar,
            City varchar
        );

sqlite> create table Orders(
            O_Id int NOT NULL,
            OrderNo int NOT NULL,
            P_Id int, 
            PRIMARY KEY (O_Id),
            FOREIGN KEY (P_Id) REFERENCES Persons(P_Id)
        );

sqlite> insert into Orders values(1,77895,3);

sqlite> select * from Orders;

1|77895|3

sqlite>

即使persons表是空行也可以插入到orders表中.

PRAGMA foreign_keys = ON;