When imports overwrite existing data

Imports are matched to existing records using unique identifiers. Once a unique ID connects an imported record to an existing record, decisions are made whether to retain or overwrite the data. 

When importing a CSV, the first step is to map fields for import. The next step is deciding whether to overwrite existing data.

overwrite existing data checkbox on imports

This checkbox refers to signup fields in your import. Signup fields are directly connected to a person's profile. If you check the box to overwrite existing data, the signup data contained in your .CSV file will permanently replace data already stored in your database.

Tags and addresses are not affected by this checkbox.

Donation imports usually add new transaction records to your financial database. Membership imports always update a person's membership information. 


Decide where the most accurate data is

Overwriting existing data is a good option if:

  • You invite people to an event and they give you their current contact information. You place this information in a spreadsheet and then upload it to your nation.
  • You attend a conference, meeting in person with people you previously only contacted online. They give you their personal contact details. You place this information in a spreadsheet and upload it to your nation.

Ultimately, you're completely confident that the information you are importing into your nation was gathered more recently and is more accurate than the information that already exists in your database.

You should not overwrite existing data if:

  • You're importing a list of people who signed a petition six months ago.
  • You're importing an event attendee list from a year ago.
  • You're importing information from a defunct chapter of your organization that hasn't been active in three years.

Basically, if you aren't confident that the information being imported is more recent and more accurate than the information in your nation, do not overwrite existing data.  

Existing data cannot be cleared by importing empty fields. With the exception of addresses, imports cannot remove data without replacing it. A few fields can be cleared using batch update. If you need help removing information from your nation, please email help@nationbuilder.com. Our services team may be able to help you.  


Importing tags

Tags will be appended to a person's profile during most imports. Tags are appended to a person's profile during a one-time import, a voter file import, and a voter history import. If you map to the "tag_list" field in a donation import, the donor's tag list will be overwritten by the tags imported. You cannot map to the "tag_list" field during a membership import.

Tags added to every record imported using the "Add tags to each person" text box on the import screen will always be appended to a profile.


Address imports

Regardless of whether the "overwrite non-blank fields" checkbox is checked, an entire address will be overwritten if one of the following fields is mapped: address1, street_name, city, zip5, or country_code.

If only registered state is imported, it will not update the registered address. The registered state imported will be used, along with the state file ID, as a unique identifier.

If only registered county and registered state are imported, the registered address will not be updated. These fields, along with the county file ID, will be used as a unique identifier.


Donation imports

In a donation import, the "overwrite existing data" checkbox refers to signup fields being imported, not to donations.

Individual donations exist in a separate table from profile information. Most donation imports will add new transactions to a nation's financial database. If you include a NationBuilder donation ID on an imported donation record, an existing donation will be updated. Mapping to a NationBuilder donation ID will always overwrite existing financial information. This is true whether or not you check the "overwrite existing data" checkbox. 


Membership imports

Similarly, membership information exists in a separate table from profile information. A person can have multiple membership types, but only one membership per type. Therefore, membership imports always update membership information associated with a person. 

The "overwrite existing data" checkbox in a membership import refers to signup fields, not to information related to a membership.


Fields available for import

Unique identifiers

Primary address and importing addresses

How to map fields for import

How to import donations

How to import memberships


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