fix: fetch document lines via $expand instead of standalone queries

The BC API v2.0 requires line entities (salesInvoiceLines, etc.) to be
accessed through their parent document - they cannot be queried directly.
Use OData $expand on parent documents to include lines inline, e.g.
salesInvoices?$expand=salesInvoiceLines

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

bc-export.ps1

@@ -18,22 +18,12 @@ $bcCompanyName = $env:BC_COMPANY_NAME  # optional: filter to specific company
 
 $baseUrl = "https://api.businesscentral.dynamics.com/v2.0/$tenantId/$environmentName/api/v2.0"
 
-# Entities to extract - critical business data
+# Standalone entities to extract
 $entities = @(
     "accounts",
     "customers",
     "vendors",
     "items",
-    "salesInvoices",
-    "salesInvoiceLines",
-    "salesOrders",
-    "salesOrderLines",
-    "salesCreditMemos",
-    "salesCreditMemoLines",
-    "purchaseInvoices",
-    "purchaseInvoiceLines",
-    "purchaseOrders",
-    "purchaseOrderLines",
     "generalLedgerEntries",
     "bankAccounts",
     "employees",
@@ -46,6 +36,16 @@ $entities = @(
     "countriesRegions"
 )
 
+# Document entities with line items - fetched with $expand to include lines
+# Lines cannot be queried standalone; they require a parent document ID
+$documentEntities = @{
+    "salesInvoices"     = "salesInvoiceLines"
+    "salesOrders"       = "salesOrderLines"
+    "salesCreditMemos"  = "salesCreditMemoLines"
+    "purchaseInvoices"  = "purchaseInvoiceLines"
+    "purchaseOrders"    = "purchaseOrderLines"
+}
+
 function Write-Log {
     param([string]$Message, [string]$Level = "INFO")
     $timestamp = Get-Date -Format "yyyy-MM-dd HH:mm:ss"
@@ -158,6 +158,48 @@ function Export-EntityData {
     }
 }
 
+function Export-DocumentWithLines {
+    param(
+        [string]$Token,
+        [string]$CompanyId,
+        [string]$CompanyName,
+        [string]$DocumentEntity,
+        [string]$LineEntity,
+        [string]$OutputDir
+    )
+
+    $entityUrl = "$baseUrl/companies($CompanyId)/$DocumentEntity" + '?$expand=' + $LineEntity
+
+    Write-Log "  Exporting $DocumentEntity (with $LineEntity)..."
+
+    try {
+        $data = Get-BCData -Token $Token -Url $entityUrl
+        $docCount = 0
+        $lineCount = 0
+        if ($data) {
+            $docCount = $data.Count
+            foreach ($doc in $data) {
+                if ($doc.$LineEntity) {
+                    $lineCount += $doc.$LineEntity.Count
+                }
+            }
+        }
+
+        # Save the documents (with lines embedded)
+        $outputFile = Join-Path $OutputDir "$DocumentEntity.json"
+        $data | ConvertTo-Json -Depth 10 | Out-File -FilePath $outputFile -Encoding utf8
+
+        Write-Log "  $DocumentEntity : $docCount documents, $lineCount lines"
+        return ($docCount + $lineCount)
+    }
+    catch {
+        Write-Log "  Failed to export ${DocumentEntity} with lines: $_" "WARN"
+        $outputFile = Join-Path $OutputDir "$DocumentEntity.json"
+        "[]" | Out-File -FilePath $outputFile -Encoding utf8
+        return 0
+    }
+}
+
 # Main execution
 try {
     Write-Log "========================================="
@@ -165,7 +207,7 @@ try {
     Write-Log "========================================="
     Write-Log "Environment: $environmentName"
     Write-Log "Output Path: $OutputPath"
-    Write-Log "Entities to extract: $($entities.Count)"
+    Write-Log "Entities to extract: $($entities.Count + $documentEntities.Count) ($($documentEntities.Count) with line items)"
 
     # Create output directory
     $exportDir = $OutputPath
@@ -217,6 +259,7 @@ try {
             New-Item -ItemType Directory -Path $companyDir -Force | Out-Null
         }
 
+        # Export standalone entities
         foreach ($entity in $entities) {
             $count = Export-EntityData `
                 -Token $token `
@@ -232,6 +275,26 @@ try {
                 $failedEntities += "$companyName/$entity"
             }
         }
+
+        # Export document entities with their line items via $expand
+        foreach ($docEntity in $documentEntities.Keys) {
+            $lineEntity = $documentEntities[$docEntity]
+
+            $count = Export-DocumentWithLines `
+                -Token $token `
+                -CompanyId $companyId `
+                -CompanyName $companyName `
+                -DocumentEntity $docEntity `
+                -LineEntity $lineEntity `
+                -OutputDir $companyDir
+
+            $totalRecords += $count
+            $totalEntities++
+
+            if ($count -eq 0) {
+                $failedEntities += "$companyName/$docEntity"
+            }
+        }
     }
 
     # Save export metadata