While customizing your import, the first thing to decide is whether to overwrite existing data. This means that the data contained in your .CSV file will permanently replace data already stored in your database.
If you check the box, the data contained in your .CSV file will permanently replace data already stored in your database. This 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 check the box 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.
Clarifications to the overwrite existing data rule
The logic around how tags are imported is not based on whether you check the "overwrite existing data" checkbox. In most imports, tags will be appended to a person's profile. If you map to the "tag_list" field in a donation import, the donor's tag list will be overwritten by the tags imported.
The "overwrite existing data" checkbox only applies to signup fields, i.e. data directly connected to a person's profile. Individual donations exist in a separate table from profile information. Using the donation import, you can add new donation records to your nation's database and you can update existing donation records. If you choose to update existing donation records by mapping to an existing NationBuilder donation ID, the import will overwrite existing financial information. This is true whether or not you check the "overwrite existing data" checkbox.
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 is available in donation and membership imports. It refers to signup fields, not to information related to a donation or membership.
Existing data cannot be cleared by importing empty fields. Imports can overwrite data with new information, they 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 contact your organizer. Our services team may be able to help you.