Key-value and document store model in DynamoDB

Introduction

This model helps you store and find data quickly using keys. It is easy to save whole documents like JSON without strict tables.

When you want to save user profiles with different details for each user.

When you need to quickly find a product by its unique ID in an online store.

When storing session data for a website where each session has different information.

When you want to keep flexible data that changes often without redesigning tables.

Syntax

DynamoDB

PutItem
{
  "TableName": "TableName",
  "Item": {
    "PrimaryKey": { "S": "key_value" },
    "Attribute1": { "S": "value1" },
    "Attribute2": { "N": "123" }
  }
}

GetItem
{
  "TableName": "TableName",
  "Key": {
    "PrimaryKey": { "S": "key_value" }
  }
}

Use PutItem to add or replace an item with a unique key.

Use GetItem to retrieve an item by its key quickly.

Examples

This saves a user with ID 'user123' and their name and age.

DynamoDB

PutItem
{
  "TableName": "Users",
  "Item": {
    "UserID": { "S": "user123" },
    "Name": { "S": "Alice" },
    "Age": { "N": "30" }
  }
}

This fetches the user with ID 'user123'.

DynamoDB

GetItem
{
  "TableName": "Users",
  "Key": {
    "UserID": { "S": "user123" }
  }
}

This stores a product with nested details as a document.

DynamoDB

PutItem
{
  "TableName": "Products",
  "Item": {
    "ProductID": { "S": "p001" },
    "Details": { "M": {
      "Name": { "S": "Laptop" },
      "Price": { "N": "999" },
      "Specs": { "M": {
        "RAM": { "S": "16GB" },
        "Storage": { "S": "512GB" }
      }}
    }}
  }
}

Sample Program

This example saves a book with its ISBN as key and then retrieves it.

DynamoDB

PutItem
{
  "TableName": "Books",
  "Item": {
    "ISBN": { "S": "978-1234567890" },
    "Title": { "S": "Learn DynamoDB" },
    "Author": { "S": "Jane Doe" },
    "Details": { "M": {
      "Pages": { "N": "250" },
      "Publisher": { "S": "Tech Books" }
    }}
  }
}

GetItem
{
  "TableName": "Books",
  "Key": {
    "ISBN": { "S": "978-1234567890" }
  }
}

Important Notes

Keys must be unique in the table to avoid overwriting data.

Document attributes can store nested data like JSON objects.

This model is great for flexible and fast lookups but not for complex joins.

Summary

Key-value and document store model uses unique keys to save and find data fast.

It allows storing flexible documents like JSON with nested details.

Ideal for simple, fast access to data without complex relationships.