lsi | lsi command provides an easy way | Command Line Interface library

I think you're off to a great start. Here's my take on implementing your first three access patterns. Keep in mind that there are many ways to model data in DynamoDB and this is just one of them.

I'm implementing your access patterns using two global secondary indexes. The base table looks like this:

The base table will implement your "get posts by region" access pattern.

For your second access pattern, "fetch posts by expiration date", I created GSI2 using the PK of the base table and an SK of the expiration time. This will let you filter for posts in a region based on the expires_at time:

Your third access pattern, "fetch post within a region by status and topic", I've opted to take a slightly different approach. I created a new field named status_topic which concatenates the status and topic fields. I then defined another GSI using the PK of the main table and an SK of status_topic. That view looks like this:

This lets you implement your third access pattern by searching GSI1 where PK = REGION# and SK = OPEN#ASTRONOMY. Notice this pattern also lets you search for posts by status: PK = REGION# and SK begins_with OPEN# or PK = REGION# and SK begins_with CLOSED#

You also mention that you have an access pattern around listing all regions. A simple way to do this would be to create a separate partition that lists all available regions:

If you have access patterns around regions (e.g. fetch region by name) or many regions, you might consider creating an item collection to store the regions:

Notice I replaced the region names with numerical ID's and moved the name into an attribute. This is to illustrate that you can make the region name separate from the unique primary key.

Hope this helps get you unstuck!

If I understand what you're asking for I think you're going to need another record for that data. What you want is a single AsOfDate for each user/product combination, where the AsOfDate is the most recent. If you add a record that is keyed on UserID and Product then you'll have exactly one record for each. To make that work you'll likely need to change your table structure to support the single table design pattern (or store this data in a different table). In a single table design you might have something like this:

Then, to get all the most recent records you query for pk = userId and begins_with(sk, 'MostRecent|'). To get the other records you query for pk = userId and begins_with(sk, 'Purchase|'). Your access pattern requirements might have you changing that some, but the idea should be similar to this.

Whenever you do a new "Purchase" you would insert the new row for that, and update the "MostRecent" row as well (you can do that in a transaction if you need to, or use a DynamoDB stream to do that update).

Yes, every time you train LDA, it forgets what it has learned so far.

Some suggestions and comments that may help you to get better results:

• Make sure that you've preprocessed the text appropriately. This usually includes removing punctuation and numbers, removing stopwords and words that are too frequent or rare, (optionally) lemmatizing the text. Preprocessing is dependent on the language and the domain of the texts.
• About the hyperparameters, you can use the "auto" mode for alpha and beta, letting the model learn the best values of alpha and beta. If you want to fix them, usually values lower than 1 are suggested. Check this
• LDA is a probabilistic model, which means that if you re-train it with the same hyperparameters, you will get different results each time.

From what I gather you have a two entities:

• Restaurant
  • ID
  • Name
• Beer
  • Name

Each restaurant may have multiple beers and each bear is either bottled or tap and also has a price.

You want to enable these access patterns:

1. Get a list of restaurants
2. Get a list of beers per restaurant
3. Get a list of beers in all restaurants

I propose a single table with a Global Secondary Index (GSI1) that looks like this:

1. To get a list of all restaurants you do a query against GSI1 with PK=RESTAURANTS

Do you try to use VMware Converter Tool ? I think that is the easy way to move your server to VMware. You can download the tool it is free. https://www.vmware.com/products/converter.html

Yes...

GSI

In a DynamoDB table, each key value must be unique. However, the key values in a global secondary index do not need to be unique.

LSI

In a DynamoDB table, the combined partition key value and sort key value for each item must be unique. However, in a local secondary index, the sort key value does not need to be unique for a given partition key value.

Input data represent complex structure. We need to extract only information of interest.

This can be achieved by utilizing an arrays with fields of interest. As the data placed into an array we have to loop through the arrays.

Please investigate following code with compliance for your task.

Lets first define all the required functionality

As we know, in typescript an enum is like a plain old javascript object(at-least what the playground js-output is showing or the log showing):

one way is using a function which generates a new object with {value:value} structure like below: