SET expression for adding/changing in DynamoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the SET expression do in DynamoDB UpdateItem?

The SET expression updates existing attributes or adds new attributes to an item in DynamoDB.

beginner

How do you add a new attribute using a SET expression?

Use SET with the attribute name and value. If the attribute doesn't exist, DynamoDB creates it with the given value.

intermediate

Can SET expression change multiple attributes at once?

Yes, you can separate multiple attribute updates with commas in a single SET expression.

intermediate

Example: How to increment a numeric attribute 'count' by 1 using SET?

Use: SET count = count + :incr where :incr is 1 in ExpressionAttributeValues.

beginner

What happens if you use SET on an attribute that already exists?

The existing attribute value is replaced with the new value specified in the SET expression.

What does the SET expression do in DynamoDB UpdateItem?

A Reads an item

B Deletes an item

C Adds or updates attributes in an item

D Creates a new table

SET expression is used to add or update attributes in an existing item.

How do you update multiple attributes in one SET expression?

A Separate attribute updates with commas in one SET expression

B Use DELETE expression

C Use multiple SET expressions separately

D Use a batch update

Multiple attributes can be updated by separating them with commas in a single SET expression.

What happens if you SET an attribute that does not exist?

A Nothing happens

B DynamoDB throws an error

C The item is deleted

D The attribute is created with the given value

If the attribute does not exist, SET creates it with the specified value.

How to increment a numeric attribute 'score' by 5 using SET?

A SET score = 5

B SET score = score + :val with :val = 5

C DELETE score

D ADD score 5

You increment by setting score = score + :val where :val is 5.

Can SET expression be used to change string attributes?

A Yes, it replaces the string value

B Only for list attributes

C Only for boolean attributes

D No, only numeric attributes

SET can update string attributes by replacing their values.

Explain how the SET expression works for adding or changing attributes in DynamoDB.

Think about how you change or add info in a notebook.

Describe how to increment a numeric attribute using SET expression in DynamoDB.

Like adding points to a score.