Using Database Toolbox to connect to and query Cosmos DB

I am new to Matlab's Database Toolbox and have limited experiences with databases in general. There is an Azure Cosmos DB that I would like to connect to and run SQL queries against. I saw MATLAB Interface for Azure Cosmos DB, but it's complex and I'm hoping there's a way to connect straight from the Database Toolbox. I am using R2020a, could update if needed though there doesn't seem to any mention of improvements related to Cosmos in the Database Toolbox release notes.

Any help on setting up the connection to the database, and running an example SQL query, would be much appreciated.

Answer 1

[KAE]

In case it helps someone else: I got extensive help from Mathworks on using the MATLAB Interface for Azure Cosmos DB and am now able to run SQL queries on my Cosmos DB and pull the results into MATLAB. Below is example code based on modifying what Mathworks provided. You can only run this after you install all the third party software required by the Interface.

%% Add Azure Cosmos DB SQL paths
% Change next line to the directory where you installed the Azure startup.m file
myAzurePath = ['C:\MyAzureInstallDirectory\matlab-azure-cosmos-db-master\' ...
    'matlab-azure-cosmos-db-master\Software\MATLAB\SQL\']; 
run([myAzurePath 'startup.m']) % Should see "Adding Azure Cosmos DB SQL Paths"

%% Set up the client & config
databaseId = 'MyDatabaseName'; % Change to your database name 
database = azure.documentdb.Database(databaseId);
docClient = azure.documentdb.DocumentClient(); % Create a document client

%% Confirm that you can connect to database
options = azure.documentdb.RequestOptions();
databaseLink = ['/dbs/',database.getId()];
if docClient.existsDatabase(databaseLink, options)
    disp('Connected successfully to database')
end

collectionId = 'MyContainerName'; % Change to your container name
collectionLink = ['/dbs/',databaseId,'/colls/',collectionId];
% Can ignore any log complaints that appear here

%% Query to retrieve first few database records
options = azure.documentdb.FeedOptions(); 
options.setEnableCrossPartitionQuery(true);

% Edit this example query, which retrieves the first 10 records
queryStr = ['SELECT TOP 10 * FROM MyContainerName c'];
response = docClient.queryDocuments(collectionLink, queryStr, options);
responseCellArray = response.getQueryCellArray();
iRecord = 1; % Get the first of the 10 records retreived
FirstRecord = jsondecode(responseCellArray{iRecord}.toJson); % Output structure containing first record

[Andrew Janke]

Hi Kae,

When creating an Azure Cosmos DB account (in the Azure Portal etc), you have to select which API to use with that account, e.g. Core (SQL), MongoDB, Cassandra, Azure Table, or Gremlin. Am I reading it right that you're using the "Core (SQL)" API here?

[Karthik]

Hi Kae, We're trying to follow the instructions listed for cosmodb connection and this is the error message we keep getting when we try to run the code with the connection settings that you have recommended

Unable to resolve the name 'com.microsoft.azure.documentdb.Database'

Please let me know if there's anything else we need to check. Thank you !!

[KAE]

I would say, contact [e-mail] for additional help since I am using this somewhat blindly. There are many details that seem to have to be correct for it to work so their help can save you time.