How to paste list of values to a table column with lookup cells

[mojopin]

Hi,

I'm building my first Access database and have a newbie problem.
I have two tables with geographical locations. All sub-regions in table 2 are contained in the regions in table 1.

Table 1:
[Region ID] [Region number] [Region name]

Table 2:
[Sub-region ID] [Sub-region number] [Sub-region name] [Region name]

I've related the tables using the wizard, and created the [Region name] column as a "lookup-column" in Table 2. Everything seems fine. I can choose regions from the dropdown list in the fourth column of Table 2, and the chosen sub-regions then appear as a "child" of the chosen "parent" in Table 1.

But as Table 2 consist of 20 000 sub-regions, I can't choose a region from the dropdown list for every record. But when pasting values to the fourth (the lookup) column of Table 2, I get the error:

"You cannot add or change a record because a related record is required in Table 1".

What am I doing wrong? All the regions I'm pasting already exist in Table 1 (i.e. I'm not adding new regions), and the formating is the same.

[ranman256]

you cant overwrite child key records if they have a parent.
you can run an update query on the child's other fields, but not the keys

[mojopin]

I'm not sure I understand. I guess my question in too elementary.

There are currently no data in the column related to the parent table. How should I import data to this column for the first time? I can't be expected to choose a value from the dropdown list for all of the 20 000 records? Should I first import the values, and then relate the two tables?