UPDATE

Synopsis

UPDATE tablename
    update_expression
    [ KEYS IN primary_keys ]
    [ WHERE expression ]
    [ USING index ]
    [ RETURNS (NONE | ( ALL | UPDATED) (NEW | OLD)) ]

Examples

UPDATE foobars SET foo = 'a';
UPDATE foobars SET foo = 'a', bar = bar + 4 WHERE id = 1 AND foo = 'b';
UPDATE foobars SET foo = if_not_exists(foo, 'a') RETURNS ALL NEW;
UPDATE foobars SET foo = list_append(foo, 'a') WHERE size(foo) < 3;
UPDATE foobars ADD foo 1, bar 4;
UPDATE foobars ADD fooset (1, 2);
UPDATE foobars REMOVE old_attribute;
UPDATE foobars DELETE fooset (1, 2);

Description

Update items in a table

Parameters

tablename
The name of the table
RETURNS
Return the items that were operated on. Default is RETURNS NONE. See the Amazon docs for UpdateItem for more detail.

Update expression

All update syntax is pulled directly from the AWS docs:

http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Modifying.html

In general, you may use any syntax mentioned in the docs, but you don’t need to worry about reserved words or passing in data as variables like :var1. DQL will handle that for you.

WHERE and KEYS IN

Both of these expressions are the same as in SELECT. Note that using KEYS IN is more efficient because DQL can perform the writes without doing a query first.