坚持在android studio上创建外键

Question

外键在Android中不起作用。我试过了：

@Override
public void onConfigure(SQLiteDatabase db) 
{
    super.onOpen(db);
    if (!db.isReadOnly()) {
        // Enable foreign key constraints
        //db.execSQL("PRAGMA foreign_keys=ON;");
        //(OR)
        db.setForeignKeyConstraintsEnabled (true);
    }
}

这就是我创建表格的方式：

db.execSQL("CREATE TABLE " + TABLE_NAME + 
    "(_id INTEGER PRIMARY AUTOINCREMENT,
    NAME TEXT, 
    SURNAME TEXT,
    MARKS INTEGER,
    SDATE TEXT )"
);

db.execSQL("CREATE TABLE " + 
    SCHOOL_TABLE_NAME +
    "(_id INTEGER PRIMARY KEY AUTOINCREMENT,
    SCHOOL TEXT, 
    LOCATION TEXT, 
    S_id INTEGER, 
    FOREIGN KEY(S_id) REFERENCES" + TABLE_NAME + "(" + COL_1 + ")" )
);

仍然没有外键。我错过了什么？请帮忙