Updating a document can alter one or more attributes already present within the document itself, or can add a new attribute. Let's pretend we made a mistake inserting Amy's year of birth and we want to change the value from 1998 to 1997; we can update the related document using the following query:

r.table('people').get('f1664276-1aad-4998-8240-410a82883115').update({"yearOfBirth": 1997})

First, we get the correct document using its primary key. Then we call the update() command, passing it a JSON document that contains the changes. In this case, the change is as follows:

({"yearOfBirth": 1997}

If we now query the database searching for Amy's document, we can see that year of birth has, in fact, been updated correctly:

Sometimes, you may want to add a new field to an existing document that has already been saved in the database. If this is the case, the update() command comes to the rescue once again. You can add a new attribute and value by passing the corresponding JSON as an argument to the update() command.

For example, we may want to add a nationality field to every document in the people table. We can do so by running the following query:

r.table('people').update({"nationality": "English"})

Note that first, we select every document by not providing a filter, and then, we chain the update() command at the end of the query. Let's edit the data once again and change Alex's nationality to Spanish:

r.table('people').filter(r.row("name").eq("Alex")).update({"nationality": "Spanish"})

Finally, we can print the name and nationality attributes of all the documents in the table to make sure that the updates have succeeded:

As you can see from the preceding screenshot, the nationality field has been added correctly, and Alex's nationality has been set to Spanish.

Now that you've learned how to insert, update, and query data, let's look at how we can remove documents from a table.