主数据库中的外键引用附加数据库(Foreign key in main database referencing attached database)

 在SQLite3中是否有任何方法在主数据库中有一个引用附加数据库中的列的外键（反之亦然？） 
 
 我希望在多个进程之间共享附加的（只读）数据库，每个进程都有自己的（读/写）主数据库。 
 
 我像这样创建父表（在数据库'ParentDB'中）： 
 
create table Parent (id integer primary key);
 
 现在我在主数据库中尝试这个： 
 
attach 'parent.sqlite3' as ParentDB;
create table Child (id integer not null references Parent (id),
                    constraint PK_Child primary key (id));
insert into ParentDB.Parent (id) values (42);
 
 当我尝试它时，它创建没有错误的外键。 现在我尝试在子表中插入一行： 
 
insert into Child (id) values (42);
 
 我收到这个错误： 
 
Error: no such table: main.Parent
 
 所以它似乎总是假设父表和子表属于同一个数据库。 
 
 外键语法也不允许您指定父表所属的数据库 。 
 
 有解决方法吗？ 
 
 
 这个问题是相关的，但是这里父表和子表都在同一个附加数据库中，而我将它们放在不同的数据库中。 

Is there any way in SQLite3 to have a foreign key in the main database that references columns in an attached database (or vice-versa?)
 
I hope to share the attached (read-only) database between multiple processes, each of which has its own (read/write) main database.
 
I create the parent table like this (in database 'ParentDB'):
 
create table Parent (id integer primary key);
 
Now I try this in the main database:
 
attach 'parent.sqlite3' as ParentDB;
create table Child (id integer not null references Parent (id),
                    constraint PK_Child primary key (id));
insert into ParentDB.Parent (id) values (42);
 
When I try it it creates the foreign key with no errors. Now I try to insert a row into the child table:
 
insert into Child (id) values (42);
 
And I get this error:
 
Error: no such table: main.Parent
 
So it seems it always assumes the parent and child tables belong to the same database.
 
Also the foreign key syntax does not allow you to specify which database the parent table belongs to.
 
Is there a workaround?
 
 
This question is related, but here both the parent and child tables are in the same attached database, whereas I have them in separate databases.

原文：https://stackoverflow.com/questions/22289837