DynamoDB PutItem does not create new item - amazon-web-services

Question

I use a lambda to detect if there is any isActive record in my table and put_item to update the id if there is.
For example, I have a placeholder record with ID 999999999, if my table query detected there's an active record (isActive = True), it will put_item with the real session_id and other data.
Table record:
My lambda has the following section (from my cloudwatch the if...else statement is working as intended to verify the logic). Please ignore indentation hiccups when i copy and paste, the code runs with no issue.
##keep "isActive = True" when there's already an active status started from other source, just updating the session_id to from 999999999 to real session_id
else:
count_1 = query["Items"][0]["count_1"] <<< from earlier part of code to retrieve from current count_1 value from the table.
print(count_1) << get the right '13' value from the current table id = '999999999'
table.put_item(
Item={
'session_id': session_id,
'isActive': True,
'count_1': count_1,
'count_2': count_2
},
ConditionExpression='session_id = :session_id AND isActive = :isActive',
ExpressionAttributeValues={
':session_id': 999999999,
':isActive': True
}
)
However my table is not getting new item nor the primary key session_id is updated. Table still stays as the image above.
I understand from the documentation that
You cannot use UpdateItem to update any primary key attributes.
Instead, you will need to delete the item, and then use PutItem to
create a new item with new attributes.
but even if put_item is not able to update primary key, at least I am expecting a new item being created from my code when there isn't any error code thrown?
Does anybody know what is happening? thanks

Answer 1

I resolved it with different specification for ConditionExpression. Did multiple troubleshooting ways and pinpoint the issue comes from ConditionExpression:
What i did instead -
add imports of boto3.dynamodb.conditions import Key & Attr
and use ConditionExpression with ConditionExpression=Attr("session_id").ne(999999999)
and delete old id item
table.delete_item(
Key={
'session_id': 999999999
}
)
Other conditions available here https://boto3.amazonaws.com/v1/documentation/api/latest/reference/customizations/dynamodb.html#ref-dynamodb-conditions
If anyone has any other better and easier way would like to learn