INSERT multiple rows with the same ID and different value in Python SQlite3

i am using SQLite3 and pyodbc on Windows with python.

i have an ID(321) wich has multiple neighbours (0-3 neighbours).

    ID             320
         322  327  325
    321  323  238  329

What i want is a list in my SQlite db wich looks like

321 322 327 320
321 322 327 325
321 323 328 329

To get the next neighbour i have to execute a query wich returns the next neighbours and stores it in a seperat database. I have to do this step 3 times to get all neighbours i need.

The Problem at the moment is, that i´m saving the neighbours by executing an Update Statement in the database, wich returns me only one neighbour.

Example: 321 323 328 329

That´s how i get the next neighbour (get_neighbours()):

    cursor = conn.cursor()
    cursor.execute("""SELECT m2.link_id, m1.link_id
            FROM database1.rdf_link AS m1 
            INNER JOIN database2.rdf_link AS m2 
            ON m1.nonref_node_id = m2.ref_node_id
            WHERE m1.link_id IN {}""".format(get_link0()))
    rows = cursor.fetchall()
    return rows

database1 and database2 are the same database i´m just INNER JOIN, because i need to check nonref with ref (neighbour1.ref = neighbour2.nonref) That´s how i can check for neighbours

After executing i get something like that:

   [(64438719, 67618608), (727938246, 727938245)]

I insert the values with the UPDATE Statement(wich only inserts the last Value):

    cursor = conn2.cursor()
    cursor.executemany("""UPDATE database SET link_id1 = ? WHERE link_id = ?""", get_neighbours())
    conn2.commit()

I also tried with the INSERT Statement but it inserted the values into new rows. The script works fine if there is only one neighbour but if i have more than one i only collect the last updatet statement and i need every neighbour.

Thanks for your help