1# Azure SQL Database
2 
3Managed relational database with ACID compliance and full SQL Server compatibility.
4 
5## When to Use
6 
7- Relational data with ACID requirements
8- Complex queries and joins
9- Existing SQL Server workloads
10- Reporting and analytics
11- Strong schema enforcement
12 
13## Authentication
14 
15**Default:** Entra-only authentication (recommended)
16- Required for subscriptions with Entra-only policies
17- More secure than SQL authentication
18- Eliminates password management
19 
20## Required Supporting Resources
21 
22| Resource | Purpose |
23|----------|---------|
24| Key Vault | Store connection strings |
25| Private Endpoint | Secure access (optional) |
26 
27## SKU Selection
28 
29| Tier | Use Case | Features |
30|------|----------|----------|
31| **Basic** | Dev/test, light workloads | 5 DTUs, 2GB |
32| **Standard** | Production workloads | 10-3000 DTUs |
33| **Premium** | High-performance | In-memory OLTP |
34| **Serverless** | Variable workloads | Auto-pause, auto-scale |
35| **Hyperscale** | Large databases | 100TB+, instant backup |
36 
37## Environment Variables
38 
39| Variable | Value | When to Set |
40|----------|-------|-------------|
41| `AZURE_PRINCIPAL_ID` | Current user's object ID | After `azd init`, before `azd provision` |
42| `AZURE_PRINCIPAL_NAME` | Current user's display name | After `azd init`, before `azd provision` |
43| `SQL_SERVER` | `{server}.database.windows.net` | Runtime (from Bicep outputs) |
44| `SQL_DATABASE` | Database name | Runtime (from Bicep outputs) |
45| `SQL_CONNECTION_STRING` | Full connection string (Key Vault) | Runtime (from Bicep outputs) |
46 
47**Set principal variables:**
48```bash
49PRINCIPAL_INFO=$(az ad signed-in-user show --query "{id:id, name:displayName}" -o json)
50azd env set AZURE_PRINCIPAL_ID $(echo $PRINCIPAL_INFO | jq -r '.id')
51azd env set AZURE_PRINCIPAL_NAME $(echo $PRINCIPAL_INFO | jq -r '.name')
52```
53 
54## References
55 
56- [Bicep Patterns](bicep.md)
57- [Entra ID Auth](auth.md)
58- [SDK Patterns](sdk.md)
59