My experiments with DynamoDB:

Been playing with this amazing machine called the Amazon Echo and I too am blown away at the way the future has talked back to me.

During the course of my travels, I discovered that while the documentation is extensive, I've come face to face with a paucity of good examples on how to do CRUD operations in DynamoDB.

My experiments involved maps, lists and sets and here are some snippets from what I could get to work by going thru the documentation and the limited content available out there. All examples were tried via Lambda functions executing in AWS, writing and reading from a DynamoDB instance in AWS.

Here is the table structure against which these were performed:

With lists:

Create:

from __future__ import print_function

import logging,time

import boto3

import botocore

import json

import decimal

import sys

from boto3.dynamodb.conditions import Key, Attr

from botocore.exceptions import ClientError

dynamodb = boto3.resource('dynamodb')

table = dynamodb.Table('Test2')

def insert_data():

    actors=["A","B","C"]

    response = table.update_item(

   Key={

        "name":"SOME_RANDOM_KEY"

   },

   UpdateExpression="set partners = :v",

   ExpressionAttributeValues={

       ':v': actors

   },

   ReturnValues="UPDATED_NEW"

    )

    print ("Insert successful!",response)

def lambda_handler(event, context):

    # TODO implement

    insert_data()

    return 'Hello from Lambda'

..gives us...

Modify:

from __future__ import print_function

import logging,time

import boto3

import botocore

import json

import decimal

import sys

from boto3.dynamodb.conditions import Key, Attr

from botocore.exceptions import ClientError

dynamodb = boto3.resource('dynamodb')

table = dynamodb.Table('Test2')

def modify_data():

    response = table.update_item(

        Key={

             "name":"SOME_RANDOM_KEY"

        },

        UpdateExpression="SET #p = list_append(#p, :v)",  

        ExpressionAttributeNames={

            '#p': 'partners'

        },

        ExpressionAttributeValues={

            ':v': ["99"]

        },

        ReturnValues="UPDATED_NEW"

    )

    print ("Update successful!",response)

def lambda_handler(event, context):

    # TODO implement

    modify_data()

    return 'Hello from Lambda'

..gives us...

Delete:

from __future__ import print_function
import logging,time
import boto3
import botocore
import json
import decimal
import sys
from boto3.dynamodb.conditions import Key, Attr
from botocore.exceptions import ClientError
dynamodb = boto3.resource('dynamodb')
table = dynamodb.Table('Test2')
def remove_data():
    response = table.update_item(
        Key={
             "name":"SOME_RANDOM_KEY"
        },
        UpdateExpression="REMOVE partners[1]",
        ReturnValues="UPDATED_NEW"
    )
    print ("Del successful!",response)
 
def lambda_handler(event, context):
    # TODO implement
    remove_data()
    return 'Hello from Lambda'

..gives us...

With Sets:

Create:

from __future__ import print_function

import logging,time

import boto3

import botocore

import json

import decimal

import sys

from boto3.dynamodb.conditions import Key, Attr

from botocore.exceptions import ClientError

dynamodb = boto3.resource('dynamodb')

table = dynamodb.Table('Test2')

def insert_data():

    actors={"A","B","C"}

    response = table.update_item(

   Key={

        "name":"SOME_RANDOM_KEY"

   },

   UpdateExpression="set partners = :v",

   ExpressionAttributeValues={

       ':v': actors

   },

   ReturnValues="UPDATED_NEW"

    )

    print ("Insert successful!",response)

    

def lambda_handler(event, context):

    # TODO implement

    insert_data()

    return 'Hello from Lambda'

..gives us..

Modify:

from __future__ import print_function

import logging,time

import boto3

import botocore

import json

import decimal

import sys

from boto3.dynamodb.conditions import Key, Attr

from botocore.exceptions import ClientError

dynamodb = boto3.resource('dynamodb')

table = dynamodb.Table('Test2')

def modify_data():

    response = table.update_item(

        Key={

             "name":"SOME_RANDOM_KEY"

        },

        UpdateExpression="ADD partners :v",  

        ExpressionAttributeValues={

            ':v': {"99"}

        },

        ReturnValues="UPDATED_NEW"

    )

    print ("Update successful!",response)

def lambda_handler(event, context):

    # TODO implement

    modify_data()

    return 'Hello from Lambda'

..gives us..

Delete:

from __future__ import print_function

import logging,time

import boto3

import botocore

import json

import decimal

import sys

from boto3.dynamodb.conditions import Key, Attr

from botocore.exceptions import ClientError

dynamodb = boto3.resource('dynamodb')

table = dynamodb.Table('Test2')

def remove_data():

    response = table.update_item(

    Key={

        "name":"SOME_RANDOM_KEY"

    },

    UpdateExpression="DELETE partners  :v ",  

    ExpressionAttributeValues={

       ':v': {"A"}    

    } ,

    ReturnValues="UPDATED_NEW"

)

    print ("Del successful!",response)

    

def lambda_handler(event, context):

    # TODO implement

    remove_data()

    return 'Hello from Lambda'

...gives us..