Updating item in DynamoDB fails for the UpdateExpression syntax - amazon-dynamodb

Question

My table data looks like below one
{
"id": {
"S": "alpha-rocket"
},
"images": {
"SS": [
"apple/value:50",
"Mango/aa:284_454_51.0.0",
"Mango/bb:291",
"Mango/cc:4"
]
},
"product": {
"S": "fruit"
}
}
Below is my code to update table. The variables I am passing to function has values product_id has alpha-rocket, image_val has 284_454_53.0.0 and image has Mango/aa:284_454_53.0.0.
I am trying to update value of Mango/aa from 284_454_51.0.0 to 284_454_53.0.0 but getting an error "The document path provided in the update expression is invalid for update"
def update_player_score(product_id, image_val, image):
dynamo = boto3.resource('dynamodb')
tbl = dynamo.Table('<TableName>')
result = tbl.update_item(
expression_attribute_names: {
"#image_name" => "image_name"
},
expression_attribute_values: {
":image_val" => image_val,
},
key: {
"product" => "fruit",
"id" => product_id,
},
return_values: "ALL_NEW",
table_name: "orcus",
update_expression: "SET images.#image_val = :image_val",
}
Is there a way to update the value of Mango/aa or replace full string "Mango/aa:284_454_51.0.0" to "Mango/aa:284_454_53.0.0"

Answer 1

You cannot update a string in a list by matching the string. If you know the index of it you can replace the value of the string by index:
SET images[1] = : image_val
It seems like maybe what you want is not a list of strings, but another map. So instead of your data looking like it does you'd make it look like this, which would allow you to do the update you're looking for:
{
"id": {
"S": "alpha-rocket"
},
"images": {
"M": {
"apple" : {
"M": {
"value": {
"S": "50"
}
},
"Mango" : {
"M": {
"aa": {
"S": "284_454_51.0.0"
},
"bb": {
"S": "291"
},
"cc": {
"S": "4"
}
}
}
},
"product": {
"S": "fruit"
}
}
I would also consider putting the different values in different "rows" in the table and using queries to build the objects.