Update item in dynamoDB

Question

I am trying to update items in DynamoDB table. The code that I have written is updating the item but when I add a column with the header "source/target", it is giving a "ValidationException" Exception.

Code used to update -

dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table("test")
response = table.update_item(
        Key={
        'id': "test_id            
        },
        UpdateExpression="set source/target= :st, user_name= :usr",
        ExpressionAttributeValues={
            ':st' : event['source/target'],
            ':usr' : event['user_name']
                },
        ReturnValues="UPDATED_NEW"
    )

The error I get is -

An error occurred (ValidationException) when calling the UpdateItem operation: Invalid UpdateExpression: Syntax error; token: \"/\", near: \"source/target\""

How to solve this?

score 6 · Accepted Answer · edited May 27 '23 at 02:07

Hi you have to use ExpressionAttributeNames when u have any special character as follows

dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table("test")
response = table.update_item(
        Key={
            'id': "test_id"
        },
        UpdateExpression="set #colName= :st, user_name= :usr",
        ExpressionAttributeValues={
            ':st' : event['source/target'],
            ':usr' : event['user_name']
        },
        ExpressionAttributeNames={
            '#colName' : 'source/target'
        },
        ReturnValues="UPDATED_NEW"
    )

score 3 · Answer 2 · edited Jun 23 '22 at 00:48

As you have used a special character in the attribute name, I think you will need to specify a ExpressionAttributeNames.

I don't know the exact syntax but it should be something like:

dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table("test")
response = table.update_item(
        Key={
        'id': "test_id"            
        },
        UpdateExpression="set #src = :st, user_name = :usr",
        ExpressionAttributeValues={
            ':st' : event['source/target'],
            ':usr' : event['user_name']
                },
        ExpressionAttributeNames={
            '#src' : 'source/target'
                },
        ReturnValues="UPDATED_NEW"
    )

Update item in dynamoDB

2 Answers2