Amazon Web Services (AWS) is a powerful expansive cloud infrastructure platform for building modern web applications.

AWS provides services for data, presentation, authentication, security, video encoding, and much more. Offering over 175 fully-featured services from data centers globally, AWS powers a large percentage of the internet.

**View and Contribute to the [Community Notes](https://github.com/eggheadio-projects/learn-aws-dynamodb-from-scratch)!**

Amazon DynamoDB is a fully managed non-relational (NoSQL) database service that provides fast and predictable performance with seamless scalability.

In other words - DynamoDB is entirely managed by AWS (so it's scaled for us, even if our startup has millions of users), it's a NoSQL database so we don't have to start by defining a detailed schema like in a relational database and it's used by companies like AirBnB, Lyft and Samsung in production.

In this lesson we're going to learn how to create a brand new DynamoDB table from scratch using AWS Console

Create a new DynamoDB table in AWS Console

An empty DynamoDB table is not really useful, the goal of a database is to... well, store data

In this lesson we're going to learn how to add a new item in a DynamoDB table, what kind of fields can we have within a a table, what does it mean that DynamoDB is an NoSQL database and how to edit an item

Add and edit an item in a DynamoDB table using AWS Console

In this quick lesson we're going to learn how to add a new DynamoDB item using a text create item menu in order to use JSON to define fields in newly added items.

As a bonus we're also going to learn what DynamoDB JSON is.

Add a new item to a DynamoDB table in AWS Console using JSON editor

Scan is the simplest type of an operation we can perform on a DynamoDB table in order to receive items from it - it's going to go through the **entire** table and return **all the items** in it (up to 1MB).

It's easy to understand but it's always a good idea to think twice before using it, since it may use your entire read capacity in one go (and this is something you may not want).

In general using `Scan` is okay when:
- you have a very small table (like the one in this video)
- you're exporting all items in your table to another storage system
- you have a very specific use case (and you know what you're doing!)

In this lesson we're going to learn how to use the `Scan` operation in AWS DynamoDB console as well as how to avoid the common misconception when it comes to using the `filter` option for `Scan` - it will **always** go through the entire table, and you can only filter the results you'll receive. Therefore, it cannot be used to "optimize" the Scan operation.



Use a DynamoDB Scan operation (carefully) in AWS Console

AWS Console is really useful but in vast majority of cases - we want to interact with our database programatically.

In this lesson we're going to learn how to create a brand new AWS Lambda function in which we'll perform a `scan` operation on a DynamoDB table.

There are quite a few topics that we'll cover:
- creating a new AWS Lambda function
- creating a brand new IAM Role with required permissions for Lambda function to read data from a DynamoDB table
- creating an environment variable within the AWS Lambda Console to store the name of the DynamoDB table
- using `AWS.DynamoDB.DocumentClient` API in order to call a `scan` operation on a DynamoDB table

Create a an AWS Lambda function to scan a DynamoDB table using DocumentClient

Learn AWS DynamoDB from scratch

https://app.egghead.io/api/v1/lessons/aws-create-a-new-dynamodb-table-in-aws-console/subtitles

Instructor: [0:00] To get started with DynamoDB, first login to your AWS account. Afterwards you can find DynamoDB under services and database. You can always search for it using this search box. I'm going to click on DynamoDB.

[0:13] I will be showing a DynamoDB landing page, because I don't yet have any DynamoDB tables on this account. What we are going to see over here is basically that DynamoDB is a fast and flexible NoSQL database service for all applications that need consistent, single-digit millisecond latency at any scale.

[0:30] What that means is that you can start small without having to create a detailed schema, because it is a NoSQL database. Once you reach a millions of users in your startup, you will still maintain the single-digit millisecond latency at any scale.

[0:43] With that being said, let me go ahead and click on create table. Next we need to provide the name for this table. I will be creating a database for all my egghead lessons. I'm going to call it myEggheadLessons.

[0:55] Next, we need to define a primary key. A primary key is made up of one of two attributes that uniquely identify items, partition the data, and sort the data within each partition.

[1:04] What that means, is that we have to be able to uniquely identify each lesson with this key. Each egghead lesson has a unique title. I'm going to specify my primary key as a LessonTitle.

[1:14] Afterwards, there's many tables that we can define, but I'm going to leave everything as default. What that means is that I will be using no secondary indexes in this table.

[1:22] The provisions capacity will bet set to five reads and writes, which is more than enough for this sample example. We will have some basic allowance for this table, and we're going to also use the default encryption type for this database.

[1:32] Next, click on Create to create our first DynamoDB table. Right now, we can see that our table is being created. This is going to take a couple of seconds, but afterwards we're going to see our freshly-created DynamoDB table.

[1:43] Now our table has been created. We can see in the table, these are sections that the table Dynamo specified as myEggheadLessons. The primary partition key was set to LessonTitle, which is a string. We don't have a sort key right now. We also provisioned five read and write capacity units for this database.

[1:59] If we go ahead and switch to the items section, we will notice that we don't have any items right now, because by default, every DynamoDB table starts completely fresh, there's nothing in it.

https://app.egghead.io/api/v1/lessons/aws-create-a-new-dynamodb-table-in-aws-console/transcript

https://app.egghead.io/api/v1/lessons/aws-add-and-edit-an-item-in-a-dynamodb-table-using-aws-console/transcript

https://app.egghead.io/api/v1/lessons/aws-add-a-new-item-to-a-dynamodb-table-in-aws-console-using-json-editor/transcript

https://app.egghead.io/api/v1/lessons/aws-use-a-dynamodb-scan-operation-carefully-in-aws-console/transcript

https://app.egghead.io/api/v1/lessons/aws-create-a-an-aws-lambda-function-to-scan-a-dynamodb-table-using-documentclient/subtitles

Instructor: [00:00] Scan operation wouldn't be terrible useful if we could only perform it via the console. Luckily, we can use code, for instance a Lambda function, to scan our table.

[00:08] In order to do that, we're going to go to Services and Lambda, and we're going to create a brand-new Lambda function in order to scan our table. I'm going to call it scanaDynamoDBTable and we are going to use no [inaudible] . Before we move on, we have to ensure that our function has the required permissions.

[00:25] By default, a Lambda function gets a basic Lambda permissions, which do not give it access to read data from a DynamoDB table. We're going to create a new customer role in order for us to be able to read the data from a table. To do that, go to Identity and Access Management console and we're going to create a brand-new role that we are also going to use in the future lessons.

[00:43] I have to create our role for the Lambda function, so I'm going to click over here. Next click on Permissions. There are two types of permissions that I need to attach to this role. First up, I need to attach basic Lambda permissions. I'm going to search for Lambda, and it is going to be over here, AWSLambdaBasicExecutionRole.

[00:59] Afterwards, I need to also attach DynamoDBReadOnlyAccess, because I would like this function to be able to only read the data from a DynamoDB table. Remember, AWS follows the principle of this privilege. The idea is that the resources have only the access to the things that they need.

[01:15] As an example, in this case, we are not going to give this function a DynamoDB full-access permissions, which are over here, because I don't want this function to be able to, for instance, delete a DynamoDB table or write data to it. I just want it to be able to read something.

[01:28] Next up, I'm going to click on Tags. For the time being, I'm not going to add any, so click on Review. We can see those two policies that we've just attached, so AWSLambdaBasicExecutionRole and AmazonDynamoDBReadOnlyAccess. I'm going to call this role DynamoDBReadOnlyLambda. This is going to allow Lambda function to read data from DynamoDB table. Now we are able to go ahead and create the role.

[01:53] Now we can see that our role has been successfully created. Let's go back to the Lambda function. Over here, instead of creating a new role with basic Lambda permissions, instead I'm going to use an existing role that we've just created. I'm going to search for DynamoDBReadOnlyLambda role. Next up, click on Create Function. Now our function has been successfully created.

[02:10] Let's go down a bit in order to implement it. In order to interact with DynamoDB from Node.js, we're going to use a DynamoDB DocumentClient, which is a high-level API that allows us to interact with DynamoDB API, without going in too deeply into different quirks of DynamoDB, so with accent for create, read, update, and delete operations.

[02:27] First up, we're going to import the AWS SDK, so const aws = require('aws-sdk'). Afterwards, I'm going to create a new DocumentClient, so const dynamo = new AWS.DynamoDB.DocumentClient, like this.

[02:43] Next, we're going to create a new function, which is going to be called, getAllLessons. This is going to be an async function and it's going to scan the entire table, so const scanResult = await dynamo.scan. Scan takes an object as an argument. Basically, we need to provide only the table name. I'm going to provide a table name, which is called my_egghead_lessons.

[03:08] Actually, a better approach would be not to hard code this table name inside of this Lambda function, and instead scrolling down a bit and using the environment variables to do that. I'm going to quickly create a new environment variable, which I'm going to call it tablename, and I'm going to pass in the value of my_egghead_lessons. Let me save that.

[03:24] Now, instead of using this hard-coded value, I'm going to do, process.env tablename. Using await requires a promise, so we have to call that promise at the end of this scan call. Afterwards, I'm going to return the scanResult.

[03:38] Let me go ahead and call this function over here. I'm going to do const data = await getAllLessons. I'm going to return this data as a response from this Lambda function. Instead of this hard-coded "Hello from Lambda" string, I'm going to simply JSON.stringify data.

[03:54] Let me go ahead and save this function, and let's test if it works. Click on Test in order to create a test event. Right now, we don't really care about what's inside of this test event, because we are not using any of it. I'm just going to clear this out, and I'm going to call it myTestEvent, scroll down and click on Create.

[04:09] One thing, there's a typo in this code. Both D and B in DynamoDB are upper case, so let me go ahead and fix that. Click on Save and let's test this function. Click on Test, and we can see the response over here. The response contains in the body all the items that we have in our database.

[04:25] To recap, in order to use a Lambda function in order to get data from DynamoDB table, first up, we need to attach a proper execution role to this function, so that it has access to a DynamoDB table resources in the first place.

[04:36] Next, we can use the DynamoDB DocumentClient API, which allows us to call different functions on a DynamoDB table, such as scan, that we see in this lesson, in order to get data from a DynamoDB table.

https://app.egghead.io/api/v1/lessons/aws-create-a-an-aws-lambda-function-to-scan-a-dynamodb-table-using-documentclient/transcript

Learn AWS DynamoDB from scratch

Tomasz Łakomy

Course Content