Tables :: 2 Similar Tables / One Takes Too Long To Append Data

I have being playing with ms access but I really don't know much about it or databases in general.I have created a very simple database to gather twitter following/followers data for research purposes.One table (table01) has a field for the "boss" user (=the user who I gather data for), another field for "client" (=bosses followers or friends).Both fields are numeric and contain the users id's.In order to distinguish if the link is follower or friend there is a third field, called type which can be either 1 (=follower) or 2 (=friend).So the data would look like this:

boss - client - type
12345, 67890, 1
12345, 54321, 2

If user with user id 12345 had a follower (type 1) with user id 67890 and a friend with user id 54321...In order to avoid getting duplicate rows I also added a unique identifier which is of the form boss_id-user_id-type.So the above row looks like this:

12345-67890-1, 12345, 67890, 1
12345-54321-2, 12345, 54321, 2

That works just fine.For several reasons I also needed data of the form source - target.So I also made another table (table02) of this form.

67890, 12345
12345, 54321
...

In table 2 you don't need the "type" field since the position of the user id shows the type of relationship.Still, you need a unique identifier in order to avoid duplicates, so I added on with the form: source_id-client_id..So table02 lookes like this

67890-12345, 67890, 12345
12345-54321, 12345, 54321
...

Both tables also have a date/time stamp for each line.As you can see, table01, having also a type field is bigger than table02.The problem is when I try to append data, exactly the same data in both tables.Appending data to table01 is ok, while appending data to table02 (which is smaller, having one less field) takes a really long time, maybe 10 times as long as appending data to table01.To make sure that no query's are causing the problem I have tried first creating temporary tables with the data to be appended, no duplicates, nothing that would cause the database to make extra calculations and used a simple update query with no filters to append data.Still I get the same result, table02 takes a very long time to finish while table01 finishes in no time.