PutItem (creating items) in DynamoDB - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the PutItem operation do in DynamoDB?

PutItem adds a new item or replaces an old item with a new one in a DynamoDB table.

beginner

Which key attribute must you always include when using PutItem?

You must include the primary key attribute(s) defined for the table, such as the partition key and optionally the sort key.

intermediate

What happens if you use PutItem with an item that has the same primary key as an existing item?

The existing item is completely replaced by the new item you provide.

intermediate

How can you prevent overwriting an existing item when using PutItem?

Use a condition expression to check that the item does not already exist before inserting.

beginner

Give an example of a simple PutItem request in DynamoDB.

Example: {"TableName": "Users", "Item": {"UserId": {"S": "123"}, "Name": {"S": "Alice"}}}

What does PutItem do if the item key already exists in the table?

A It replaces the entire existing item with the new item.

B It deletes the old item and inserts the new one.

C It updates only the specified attributes.

D It returns an error and does nothing.

PutItem replaces the entire existing item with the new item if the primary key matches.

Which attribute is mandatory in the Item you provide to PutItem?

A The primary key attribute(s) of the table.

B Any attribute you want to add.

C A timestamp attribute.

D A condition expression.

The primary key attribute(s) must be included to uniquely identify the item.

How can you avoid overwriting an existing item when using PutItem?

A Delete the item first.

B Use UpdateItem instead.

C Use a condition expression to check item existence.

D PutItem always overwrites; you cannot avoid it.

A condition expression can prevent PutItem from overwriting if the item already exists.

What is the minimum required parameter for a PutItem request?

A TableName only.

B TableName and Item.

C Item only.

D ConditionExpression.

You must specify the table name and the item to insert.

If you want to add a new user with ID '101' and name 'Bob', which is a valid PutItem Item format?

A {"UserId": {"N": "101"}, "Name": {"S": "Bob"}}

B {"UserId": "101", "Name": "Bob"}

C {"UserId": 101, "Name": "Bob"}

D {"UserId": {"S": "101"}, "Name": {"S": "Bob"}}

DynamoDB expects attribute values with types, e.g., {"S": "string"} for strings.

Explain how PutItem works in DynamoDB and what happens if the item key already exists.

Think about inserting and overwriting items.

Describe how to prevent overwriting an existing item when using PutItem.

Conditions can control when PutItem succeeds.