chore(bigquery): update object table docs

bigquery/biglake/bigquery_create_object_table/main.tf

@@ -13,33 +13,39 @@
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
-/*
-* This sample demonstrates how to create an Object Table in BigQuery.
-* For more information please refer to:
-* https://cloud.google.com/bigquery/docs/object-table-introduction
-* https://cloud.google.com/bigquery/docs/object-tables
-*/
+/**
+ * This Terraform example creates an object table in BigQuery.
+ * For more information, see
+ * https://cloud.google.com/bigquery/docs/object-table-introduction
+ * and
+ * https://cloud.google.com/bigquery/docs/object-tables
+ */
 
 # [START bigquery_create_object_table]
+# This queries the provider for project information.
+data "google_project" "main" {}
+
+# This creates a connection in the US region named "my-connection-id".
+# This connection is used to access the bucket.
 resource "google_bigquery_connection" "default" {
   connection_id = "my-connection-id"
   location      = "US"
   cloud_resource {}
 }
 
-data "google_project" "project" {}
-
+# This grants the previous connection IAM role access to the bucket.
 resource "google_project_iam_member" "default" {
   role    = "roles/storage.objectViewer"
-  project = data.google_project.project.project_id
+  project = data.google_project.main.project_id
   member  = "serviceAccount:${google_bigquery_connection.default.cloud_resource[0].service_account_id}"
 }
 
+# This defines a Google BigQuery dataset.
 resource "google_bigquery_dataset" "default" {
   dataset_id = "my_dataset_id"
 }
 
-# Cloud Storage bucket name must be unique
+# This creates a bucket in the US region named "my-bucket" with a pseudorandom suffix.
 resource "random_id" "bucket_name_suffix" {
   byte_length = 8
 }
@@ -50,6 +56,7 @@ resource "google_storage_bucket" "default" {
   uniform_bucket_level_access = true
 }
 
+# This defines a BigQuery object table with manual metadata caching.
 resource "google_bigquery_table" "default" {
   deletion_protection = false
   table_id            = "my-table-id"
@@ -59,13 +66,11 @@ resource "google_bigquery_table" "default" {
     autodetect    = false
     # REQUIRED for object tables.
     object_metadata = "SIMPLE"
-
+    # This defines the source for the prior object table.
     source_uris = [
       "gs://${google_storage_bucket.default.name}/*",
     ]
 
-    # `MANUAL` for manual metadata refresh
-    # `AUTOMATIC` for automatic metadata refresh.
     metadata_cache_mode = "MANUAL"
   }
 
@@ -74,9 +79,8 @@ resource "google_bigquery_table" "default" {
   # Interval literal: https://cloud.google.com/bigquery/docs/reference/standard-sql/lexical#interval_literals
   # max_staleness = "0-0 0 10:0:0"
 
-  # Ensure the connection can access the bucket before table creation.
-  # Without this dependency, Terraform may try to create the table when
-  # the connection does not have the correct IAM Role resulting in failures.
+  # This ensures that the connection can access the bucket
+  # before Terraform creates a table.
   depends_on = [
     google_project_iam_member.default
   ]