Working with DynamoDB using Python (Hash Key, Range Key and Indexes Explained)

ddb.ipynb

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   "source": [
    "# Working with DynamoDB using Python\n",
    "\n",
    "\n",
    "- [DynamoDB Core Components](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.CoreComponents.html)\n",
    "- [Indexes in DynamoDB](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/SecondaryIndexes.html)\n",
    "\n",
    "- [Boto3 Configuration](https://boto3.amazonaws.com/v1/documentation/api/latest/guide/configuration.html)\n",
    "\n",
    "- [DynamoDB boto3](https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/dynamodb.html)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Attributes:\n",
    "- student_id\n",
    "- course\n",
    "- year\n",
    "- grade\n",
    "\n",
    "### Key Schema:\n",
    "- Hash key: student_id\n",
    "- Range key: course\n",
    "\n",
    "\n",
    "### Global Secondary Indexes:\n",
    "- course-year-index\n",
    "    - Hash key: course\n",
    "    - Range key: year\n",
    "    \n",
    "### Local Secondary Indexes:\n",
    "- year-index\n",
    "    - Range key: year\n",
    "    \n",
    "### Operations:\n",
    "- Put item\n",
    "- Get item\n",
    "- Get all records for a student_id\n",
    "- Get all records for a student_id from a given year\n",
    "- Get all records for a given course and year"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import boto3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "ddb = boto3.resource('dynamodb', \n",
    "                     aws_access_key_id='xxxxxxxxxxxxxxx', \n",
    "                     aws_secret_access_key='xxxxxxxxxxxxxxxxxxxxxxxxxx')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "table = ddb.Table('AcademicRecords')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "items = [\n",
    "    {\n",
    "        'student_id': 'nikhil',\n",
    "        'course': 'Science',\n",
    "        'year': '2015',\n",
    "        'grade': 9\n",
    "    },\n",
    "    {\n",
    "        'student_id': 'nikhil',\n",
    "        'course': 'English',\n",
    "        'year': '2016',\n",
    "        'grade': 10\n",
    "    },\n",
    "    {\n",
    "        'student_id': 'ravi',\n",
    "        'course': 'English',\n",
    "        'year': '2016',\n",
    "        'grade': 9\n",
    "    }\n",
    "]\n",
    "\n",
    "for item in items:\n",
    "    table.put_item(Item=item)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'Items': [{'year': '2016',\n",
       "   'student_id': 'ravi',\n",
       "   'grade': Decimal('9'),\n",
       "   'course': 'English'},\n",
       "  {'year': '2016',\n",
       "   'student_id': 'nikhil',\n",
       "   'grade': Decimal('10'),\n",
       "   'course': 'English'},\n",
       "  {'year': '2015',\n",
       "   'student_id': 'nikhil',\n",
       "   'grade': Decimal('9'),\n",
       "   'course': 'Science'}],\n",
       " 'Count': 3,\n",
       " 'ScannedCount': 3,\n",
       " 'ResponseMetadata': {'RequestId': 'EER3IDEK54PQ9MRNMQ1EGVUMEJVV4KQNSO5AEMVJF66Q9ASUAAJG',\n",
       "  'HTTPStatusCode': 200,\n",
       "  'HTTPHeaders': {'server': 'Server',\n",
       "   'date': 'Sat, 15 Feb 2020 16:55:12 GMT',\n",
       "   'content-type': 'application/x-amz-json-1.0',\n",
       "   'content-length': '316',\n",
       "   'connection': 'keep-alive',\n",
       "   'x-amzn-requestid': 'EER3IDEK54PQ9MRNMQ1EGVUMEJVV4KQNSO5AEMVJF66Q9ASUAAJG',\n",
       "   'x-amz-crc32': '683477306'},\n",
       "  'RetryAttempts': 0}}"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "table.scan()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'year': '2015',\n",
       " 'student_id': 'nikhil',\n",
       " 'grade': Decimal('9'),\n",
       " 'course': 'Science'}"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "table.get_item(Key={\n",
    "    'student_id': 'nikhil',\n",
    "    'course': 'Science'\n",
    "})['Item']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[{'year': '2016',\n",
       "  'student_id': 'nikhil',\n",
       "  'grade': Decimal('10'),\n",
       "  'course': 'English'},\n",
       " {'year': '2015',\n",
       "  'student_id': 'nikhil',\n",
       "  'grade': Decimal('9'),\n",
       "  'course': 'Science'}]"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "table.query(KeyConditionExpression=\"student_id = :student_id\", \n",
    "            ExpressionAttributeValues={\n",
    "                ':student_id': 'nikhil'\n",
    "            })['Items']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[{'year': '2016',\n",
       "  'student_id': 'nikhil',\n",
       "  'grade': Decimal('10'),\n",
       "  'course': 'English'}]"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "table.query(IndexName='year-index', \n",
    "            KeyConditionExpression=\"student_id = :student_id and #year = :year\",\n",
    "            ExpressionAttributeNames={\n",
    "                '#year': 'year'\n",
    "            },\n",
    "            ExpressionAttributeValues={\n",
    "                ':student_id': 'nikhil',\n",
    "                ':year': '2016'\n",
    "            })['Items']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[{'year': '2016',\n",
       "  'grade': Decimal('9'),\n",
       "  'student_id': 'ravi',\n",
       "  'course': 'English'},\n",
       " {'year': '2016',\n",
       "  'grade': Decimal('10'),\n",
       "  'student_id': 'nikhil',\n",
       "  'course': 'English'}]"
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "table.query(IndexName='course-year-index', \n",
    "            KeyConditionExpression=\"course = :course and #year = :year\",\n",
    "            ExpressionAttributeNames={\n",
    "                '#year': 'year'\n",
    "            },\n",
    "            ExpressionAttributeValues={\n",
    "                ':course': 'English',\n",
    "                ':year': '2016'\n",
    "            })['Items']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
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   "source": []
  }
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