dotnet add package Azure.ResourceManager.Sql
dotnet add package Azure.Identity

AZURE_SUBSCRIPTION_ID=<your-subscription-id>
# For service principal auth (optional)
AZURE_TENANT_ID=<tenant-id>
AZURE_CLIENT_ID=<client-id>
AZURE_CLIENT_SECRET=<client-secret>

using Azure.Identity;
using Azure.ResourceManager;
using Azure.ResourceManager.Sql;

// Always use DefaultAzureCredential
var credential = new DefaultAzureCredential();
var armClient = new ArmClient(credential);

// Get subscription
var subscriptionId = Environment.GetEnvironmentVariable("AZURE_SUBSCRIPTION_ID");
var subscription = armClient.GetSubscriptionResource(
    new ResourceIdentifier($"/subscriptions/{subscriptionId}"));

ArmClient
└── SubscriptionResource
    └── ResourceGroupResource
        └── SqlServerResource
            ├── SqlDatabaseResource
            ├── ElasticPoolResource
            │   └── ElasticPoolDatabaseResource
            ├── SqlFirewallRuleResource
            ├── FailoverGroupResource
            ├── ServerBlobAuditingPolicyResource
            ├── EncryptionProtectorResource
            └── VirtualNetworkRuleResource

using Azure.ResourceManager.Sql;
using Azure.ResourceManager.Sql.Models;

// Get resource group
var resourceGroup = await subscription
    .GetResourceGroupAsync("my-resource-group");

// Define server
var serverData = new SqlServerData(AzureLocation.EastUS)
{
    AdministratorLogin = "sqladmin",
    AdministratorLoginPassword = "YourSecurePassword123!",
    Version = "12.0",
    MinimalTlsVersion = SqlMinimalTlsVersion.Tls1_2,
    PublicNetworkAccess = ServerNetworkAccessFlag.Enabled
};

// Create server (long-running operation)
var serverCollection = resourceGroup.Value.GetSqlServers();
var operation = await serverCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-sql-server",
    serverData);

SqlServerResource server = operation.Value;

var databaseData = new SqlDatabaseData(AzureLocation.EastUS)
{
    Sku = new SqlSku("S0") { Tier = "Standard" },
    MaxSizeBytes = 2L * 1024 * 1024 * 1024, // 2 GB
    Collation = "SQL_Latin1_General_CP1_CI_AS",
    RequestedBackupStorageRedundancy = SqlBackupStorageRedundancy.Local
};

var databaseCollection = server.GetSqlDatabases();
var dbOperation = await databaseCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-database",
    databaseData);

SqlDatabaseResource database = dbOperation.Value;

var poolData = new ElasticPoolData(AzureLocation.EastUS)
{
    Sku = new SqlSku("StandardPool")
    {
        Tier = "Standard",
        Capacity = 100 // 100 eDTUs
    },
    PerDatabaseSettings = new ElasticPoolPerDatabaseSettings
    {
        MinCapacity = 0,
        MaxCapacity = 100
    }
};

var poolCollection = server.GetElasticPools();
var poolOperation = await poolCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "my-elastic-pool",
    poolData);

ElasticPoolResource pool = poolOperation.Value;

var databaseData = new SqlDatabaseData(AzureLocation.EastUS)
{
    ElasticPoolId = pool.Id
};

await databaseCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "pooled-database",
    databaseData);

// Allow Azure services
var azureServicesRule = new SqlFirewallRuleData
{
    StartIPAddress = "0.0.0.0",
    EndIPAddress = "0.0.0.0"
};

var firewallCollection = server.GetSqlFirewallRules();
await firewallCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "AllowAzureServices",
    azureServicesRule);

// Allow specific IP range
var clientRule = new SqlFirewallRuleData
{
    StartIPAddress = "203.0.113.0",
    EndIPAddress = "203.0.113.255"
};

await firewallCollection.CreateOrUpdateAsync(
    WaitUntil.Completed,
    "AllowClientIPs",
    clientRule);

// List all servers in subscription
await foreach (var srv in subscription.GetSqlServersAsync())
{
    Console.WriteLine($"Server: {srv.Data.Name} in {srv.Data.Location}");
}

// List databases in a server
await foreach (var db in server.GetSqlDatabases())
{
    Console.WriteLine($"Database: {db.Data.Name}, SKU: {db.Data.Sku?.Name}");
}

// List elastic pools
await foreach (var ep in server.GetElasticPools())
{
    Console.WriteLine($"Pool: {ep.Data.Name}, DTU: {ep.Data.Sku?.Capacity}");
}

// Build connection string (server FQDN is predictable)
var serverFqdn = $"{server.Data.Name}.database.windows.net";
var connectionString = $"Server=tcp:{serverFqdn},1433;" +
    $"Initial Catalog={database.Data.Name};" +
    "Persist Security Info=False;" +
    $"User ID={server.Data.AdministratorLogin};" +
    "Password=<your-password>;" +
    "MultipleActiveResultSets=False;" +
    "Encrypt=True;" +
    "TrustServerCertificate=False;" +
    "Connection Timeout=30;";

using Azure;

try
{
    var operation = await serverCollection.CreateOrUpdateAsync(
        WaitUntil.Completed, serverName, serverData);
}
catch (RequestFailedException ex) when (ex.Status == 409)
{
    Console.WriteLine("Server already exists");
}
catch (RequestFailedException ex) when (ex.Status == 400)
{
    Console.WriteLine($"Invalid request: {ex.Message}");
}
catch (RequestFailedException ex)
{
    Console.WriteLine($"ARM Error: {ex.Status} - {ex.ErrorCode}: {ex.Message}");
}