Passing the AZ-203 exam - Part 3

April 19, 2020

Develop Azure Infrastructure as a Service Solutions

This is Part 3 of the AZ-203 study guide. In this post we'll cover:

Azure Storage

Familiarize yourself on how to query data and apply filters from C# with TableQuery.GenerateFilterCondition and TableQuery.Where

public static async Task<List<User>> FindUsersAsync(CloudTable table, string name)
    // ⚠️ Remember how to create filters!
    var filterCondition = TableQuery.GenerateFilterCondition(
    var query = new TableQuery<User>.Where(filterCondition);
    var results = await table.ExecuteQuerySegmentedAsync(query, null);    
    return results.ToList();

Do checkout the other methods such as TableOperation.Retrieve, TableOperation.Delete

Cosmos DB

Create a Cosmos DB account

az cosmosdb create
    -g "my-resource-group-name"
    --name "cosmosDBaccountname"
    --kind GlobalDocumentDB  # MongoDB | Cassandra | Gremlin

Create a database

az cosmosdb database create
    - g "my-resource-group-name"
    --name "cosmosDBaccountname"
    --db-name "my-database"

Consistency Models

Read up on the different Azure Cosmos DB Consistency Levels and know when to use them, specially the Strong and Bounded Staleness (the most expensive ones, by the way).

Azure Cosmos DB Consistency Levels

# ⚠️ How do you ensure reads reflect the most recent write". 
With a strong consistency level.

Blob Storage

The exam tends to ask questions about concurrency control in blobs. This involves using leases to checkout and block files so only you can update.

var leaseId = Guid.NewGuid().ToString();

cloudBlockBlob.AcquireLease(TimeSpan.FromSeconds(30), leaseId);

await cloudBlockBlob.ReleaseLeaseAsync(new AccessCondition()
    LeaseId = leaseId

Next up...

Go to Part 4 of the series on Azure Security

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Written by Carlos Torres a software engineer who loves building things Follow him on Twitter