DynamoDB Read data

DynamoDB থেকে data read

1️⃣ AWS CLI

DynamoDB তে data read করার জন্য প্রধানত 3 operation আছে:

GetItem → Primary key দিয়ে এক record fetch
Query → Partition Key (and optionally Sort Key) দিয়ে multiple records fetch
Scan → Table এর সব record fetch (expensive, use carefully)

1.1 GetItem

aws dynamodb get-item \
  --table-name Users \
  --key '{"user_id": {"S": "1"}}' \
  --endpoint-url http://localhost:8000

Explanation:

--table-name → Table name
--key → Primary key in JSON format (Partition + Sort key if applicable)
--endpoint-url → Local Docker DynamoDB

1.2 Query (Partition Key)

aws dynamodb query \
  --table-name Users \
  --key-condition-expression "user_id = :uid" \
  --expression-attribute-values '{":uid":{"S":"1"}}' \
  --endpoint-url http://localhost:8000

Query multiple items with same Partition Key (and optional Sort Key)

Returns items in a list

1.3 Scan (Full table read)

aws dynamodb scan \
  --table-name Users \
  --endpoint-url http://localhost:8000

Table এর সব rows return করবে

Large table হলে expensive → avoid in production

2️⃣ Python

Python boto3 দিয়ে read operations অনেক সহজ:

2.1 GetItem

import boto3

dynamodb = boto3.resource('dynamodb', endpoint_url='http://localhost:8000', region_name='us-east-1')
table = dynamodb.Table('Users')

response = table.get_item(
    Key={'user_id': '1'}
)

item = response.get('Item')
print(item)

Partition Key + Sort Key (if any) দিতে হবে

Returns dict object

2.2 Query (Partition Key + optional Sort Key)

from boto3.dynamodb.conditions import Key

response = table.query(
    KeyConditionExpression=Key('user_id').eq('1')
)

items = response['Items']
print(items)

KeyConditionExpression দিয়ে filter by primary key

Returns list of items

2.3 Scan (Full table read)

response = table.scan()
items = response['Items']
print(items)

Table এর সব rows return করে

Large table এ performance cost বেশি

✅ Summary / Recommendation

Operation	AWS CLI	Python boto3	Use case
Single record	`get-item`	`get_item()`	Primary key দিয়ে fetch
Multiple records by PK	`query`	`query()`	Partition Key + optional Sort Key
Full table	`scan`	`scan()`	Debug / small table

💡 Pro Tip:

Query always preferred over Scan (fast & cheap)

Python boto3 gives more control + CLI not required

Header Ads