PutItem (creating items) in DynamoDB - Step-by-Step Execution

Concept Flow - PutItem (creating items)

Start PutItem Request

↓

Check Table Exists

↓

Validate Item Format

↓

Insert or Replace Item

↓

Return Success Response

↓

End

The PutItem operation starts by checking the table, validates the item, inserts or replaces it, then returns success.

Execution Sample

DynamoDB

PutItem {
  TableName: 'Users',
  Item: { 'UserID': '123', 'Name': 'Alice' }
}

This command adds a new item with UserID 123 and Name Alice to the Users table.

Execution Table

Step	Action	Input/Condition	Result/Output
1	Receive PutItem request	{TableName: 'Users', Item: {UserID:'123', Name:'Alice'}}	Request accepted
2	Check if table 'Users' exists	Table 'Users' exists	Proceed
3	Validate item format	Item has UserID and Name	Valid item
4	Insert or replace item in table	Item UserID='123'	Item added/replaced
5	Return success response	Operation successful	Success message sent
6	End	No more steps	PutItem operation complete

💡 PutItem completes after inserting or replacing the item and returning success.

Variable Tracker

Variable	Start	After Step 2	After Step 4	Final
TableName	undefined	'Users'	'Users'	'Users'
Item	undefined	{UserID:'123', Name:'Alice'}	{UserID:'123', Name:'Alice'}	{UserID:'123', Name:'Alice'}
OperationStatus	undefined	pending	success	success

Key Moments - 2 Insights

Why does PutItem replace an existing item with the same key instead of adding a new one?

PutItem uses the primary key to identify items. If an item with the same key exists, it replaces it. See execution_table step 4 where the item is added or replaced.

What happens if the table does not exist?

PutItem will fail at step 2 when checking the table. The operation stops and returns an error because the table must exist to insert items.

Visual Quiz - 3 Questions

Look at the execution_table, what is the result after step 3?

A Item is invalid

B Table does not exist

C Item is valid

D Operation failed

💡 Hint

Check the 'Result/Output' column for step 3 in execution_table

At which step does the item get inserted or replaced in the table?

A Step 3

B Step 4

C Step 2

D Step 5

💡 Hint

Look for the action 'Insert or replace item' in execution_table

If the table 'Users' did not exist, what would happen?

A PutItem would fail at step 2

B PutItem would create the table automatically

C PutItem would skip validation and insert anyway

D PutItem would return success without inserting

💡 Hint

Refer to key_moments about table existence and execution_table step 2

Concept Snapshot

PutItem adds or replaces an item in a DynamoDB table.
You must specify the table name and the item with its primary key.
If the item key exists, it replaces the old item.
If the table doesn't exist, the operation fails.
PutItem returns success after inserting or replacing the item.

Full Transcript

The PutItem operation in DynamoDB starts by receiving a request with a table name and an item to add. It first checks if the specified table exists. If the table is found, it validates the item format to ensure it has the required primary key. Then, it inserts the item into the table or replaces an existing item with the same key. Finally, it returns a success response to confirm the operation completed. If the table does not exist, the operation stops and returns an error. This process ensures items are correctly added or updated in the database.