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A Building Primer

Written by Greg Gimlick Get started with the basics Feature As seen in the October 2020 issue of Model Aviation 01. The is the author and his Old School Model Works Comet. 02. The Comet looks great in the air. I’ve received many questions lately about building kits and scratch-building. One of the clubs that I belong to regularly held meetings for people who hadn’t built before to learn from those who had. Obviously, those have been suspended, but they continue as best they can with online sessions. They encourage all sorts of construction methods, but I…

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( ! ) Fatal error: Uncaught TypeError: Drupal\Core\Database\StatementWrapperIterator::__construct(): Argument #2 ($clientConnection) must be of type object, null given, called in /var/www/html/web/core/lib/Drupal/Core/Database/Connection.php on line 441 and defined in /var/www/html/web/core/lib/Drupal/Core/Database/StatementWrapperIterator.php on line 38
( ! ) TypeError: Drupal\Core\Database\StatementWrapperIterator::__construct(): Argument #2 ($clientConnection) must be of type object, null given, called in /var/www/html/web/core/lib/Drupal/Core/Database/Connection.php on line 441 in /var/www/html/web/core/lib/Drupal/Core/Database/StatementWrapperIterator.php on line 38
Call Stack
#TimeMemoryFunctionLocation
14.421528709048_drupal_exception_handler( $exception = class TypeError { protected $message = 'Drupal\\Core\\Database\\StatementWrapperIterator::__construct(): Argument #2 ($clientConnection) must be of type object, null given, called in /var/www/html/web/core/lib/Drupal/Core/Database/Connection.php on line 441'; private string ${Error}string = ''; protected $code = 0; protected string $file = '/var/www/html/web/core/lib/Drupal/Core/Database/StatementWrapperIterator.php'; protected int $line = 38; private array ${Error}trace = [0 => [...], 1 => [...], 2 => [...], 3 => [...], 4 => [...], 5 => [...], 6 => [...], 7 => [...], 8 => [...], 9 => [...], 10 => [...]]; private ?Throwable ${Error}previous = NULL } ).../bootstrap.inc:0
24.422828629208_drupal_exception_handler_additional( $exception = class TypeError { protected $message = 'Drupal\\Core\\Database\\StatementWrapperIterator::__construct(): Argument #2 ($clientConnection) must be of type object, null given, called in /var/www/html/web/core/lib/Drupal/Core/Database/Connection.php on line 441'; private string ${Error}string = ''; protected $code = 0; protected string $file = '/var/www/html/web/core/lib/Drupal/Core/Database/StatementWrapperIterator.php'; protected int $line = 38; private array ${Error}trace = [0 => [...], 1 => [...], 2 => [...], 3 => [...], 4 => [...], 5 => [...], 6 => [...], 7 => [...], 8 => [...], 9 => [...], 10 => [...]]; private ?Throwable ${Error}previous = NULL }, $exception2 = class TypeError { protected $message = 'Drupal\\Core\\Database\\StatementWrapperIterator::__construct(): Argument #2 ($clientConnection) must be of type object, null given, called in /var/www/html/web/core/lib/Drupal/Core/Database/Connection.php on line 441'; private string ${Error}string = ''; protected $code = 0; protected string $file = '/var/www/html/web/core/lib/Drupal/Core/Database/StatementWrapperIterator.php'; protected int $line = 38; private array ${Error}trace = [0 => [...], 1 => [...], 2 => [...], 3 => [...], 4 => [...], 5 => [...], 6 => [...], 7 => [...], 8 => [...], 9 => [...], 10 => [...], 11 => [...], 12 => [...]]; private ?Throwable ${Error}previous = NULL } ).../bootstrap.inc:126
34.422828629208error_displayable( $error = ??? ).../bootstrap.inc:142
44.422828629208_drupal_get_error_level( ).../errors.inc:118
54.422828629208Drupal::config( $name = 'system.logging' ).../errors.inc:331
64.422828629208Drupal\Core\Config\ConfigFactory->get( $name = 'system.logging' ).../Drupal.php:421
74.422828629208Drupal\Core\Config\ConfigFactory->doGet( $name = 'system.logging', $immutable = ??? ).../ConfigFactory.php:89
84.422828629424Drupal\Core\Config\ConfigFactory->doLoadMultiple( $names = [0 => 'system.logging'], $immutable = TRUE ).../ConfigFactory.php:104
94.422828629536Drupal\Core\Config\CachedStorage->readMultiple( $names = [0 => 'system.logging'] ).../ConfigFactory.php:165
104.422828630160Drupal\Core\Cache\DatabaseBackend->getMultiple( $cids = [0 => 'system.logging'], $allow_invalid = ??? ).../CachedStorage.php:87
114.422828631320Drupal\Core\Database\Connection->query( $query = 'SELECT [cid], [data], [created], [expire], [serialized], [tags], [checksum] FROM {cache_config} WHERE [cid] IN ( :cids[] ) ORDER BY [cid]', $args = [':cids[]' => [0 => 'system.logging']], $options = ??? ).../DatabaseBackend.php:131
124.422928632368Drupal\Core\Database\Connection->prepareStatement( $query = 'SELECT [cid], [data], [created], [expire], [serialized], [tags], [checksum] FROM {cache_config} WHERE [cid] IN ( :cids__0 ) ORDER BY [cid]', $options = ['fetch' => enum Drupal\Core\Database\Statement\FetchAs::Object, 'allow_delimiter_in_query' => FALSE, 'allow_square_brackets' => FALSE, 'pdo' => []], $allow_row_count = ??? ).../Connection.php:664
134.422928632880Drupal\Core\Database\StatementWrapperIterator->__construct( $connection = class Drupal\mysql\Driver\Database\mysql\Connection { protected $target = 'default'; protected $key = 'default'; protected $logger = NULL; protected $driverClasses = ['PagerSelectExtender' => 'PagerSelectExtender']; protected $statementWrapperClass = 'Drupal\\Core\\Database\\StatementWrapperIterator'; protected $transactionalDDLSupport = FALSE; protected $connection = NULL; protected $connectionOptions = ['database' => 'dpl_jsvvhikdao', 'username' => 'vdmompnaig', 'password' => 'jC21cXfOuRnJw5HFKE', 'host' => 'devpanel-cluster-agebjmjp-aurora-cluster.cluster-coyf2dezrpfe.us-east-2.rds.amazonaws.com', 'port' => '3306', 'driver' => 'mysql', 'prefix' => '', 'collation' => 'utf8mb4_general_ci', 'namespace' => 'Drupal\\mysql\\Driver\\Database\\mysql', 'autoload' => 'core/modules/mysql/src/Driver/Database/mysql/', 'pdo' => [...], 'init_commands' => [...]]; protected $schema = class Drupal\mysql\Driver\Database\mysql\Schema { protected $connection = ...; protected $placeholder = 6; protected $defaultSchema = 'public'; protected $uniqueIdentifier = '34bc5cd799dcdae8afe672f7'; protected $mysqlStringTypes = [...] }; protected string $prefix = ''; protected array $tablePlaceholderReplacements = [0 => '"', 1 => '"']; protected $escapedTables = ['cache_container' => 'cache_container', 'cache_page' => 'cache_page', 'cache_config' => 'cache_config', 'config' => 'config', 'cache_discovery' => 'cache_discovery', 'cache_bootstrap' => 'cache_bootstrap', 'path_alias' => 'path_alias', 'cache_data' => 'cache_data', 'router' => 'router', 'cache_entity' => 'cache_entity', 'cache_routes' => 'cache_routes', 'magazine_paywall_anon_views' => 'magazine_paywall_anon_views', 'cache_dynamic_page_cache' => 'cache_dynamic_page_cache', 'cache_render' => 'cache_render', 'comment_field_data' => 'comment_field_data', 'comment' => 'comment', 'comment__comment_body' => 'comment__comment_body', 'cache_default' => 'cache_default', 'node_field_data' => 'node_field_data', 'node__field_articles' => 'node__field_articles', 'media' => 'media', 'media_field_data' => 'media_field_data', 'media_revision' => 'media_revision', 'media__field_media_image' => 'media__field_media_image', 'file_managed' => 'file_managed', 's3fs_file' => 's3fs_file', 'semaphore' => 'semaphore', 'key_value' => 'key_value', 'cache_menu' => 'cache_menu', 'menu_tree' => 'menu_tree', 'node_revision' => 'node_revision', 'users_data' => 'users_data', 'cachetags' => 'cachetags']; protected $escapedFields = ['' => '', 'collection' => '"collection"', 'name' => '"name"', 'config.name' => '"config"."name"', 'base_table.status' => '"base_table"."status"', 'base_table.alias' => '"base_table"."alias"', 'base_table.langcode' => '"base_table"."langcode"', 'base_table.id' => '"base_table"."id"', 'base_table.path' => '"base_table"."path"', 'cid' => '"cid"', 'expire' => '"expire"', 'created' => '"created"', 'tags' => '"tags"', 'checksum' => '"checksum"', 'data' => '"data"', 'serialized' => '"serialized"', 'table_schema' => '"table_schema"', 'table_name' => '"table_name"', 'table_type' => '"table_type"', 'viewer_key' => '"viewer_key"', 'viewed' => '"viewed"', 'v.nid' => '"v"."nid"', 'v.viewed' => '"v"."viewed"', 'c.entity_id' => '"c"."entity_id"', 'c.entity_type' => '"c"."entity_type"', 'c.field_name' => '"c"."field_name"', 'c.default_langcode' => '"c"."default_langcode"', 'c.status' => '"c"."status"', 'c.cid' => '"c"."cid"', 'thread_order' => '"thread_order"', 'base.cid' => '"base"."cid"', 'base.comment_type' => '"base"."comment_type"', 'base.uuid' => '"base"."uuid"', 'base.langcode' => '"base"."langcode"', '[comment_field_data].[cid]' => '"comment_field_data"."cid"', 'comment_field_data.langcode' => '"comment_field_data"."langcode"', 'comment__comment_body.comment_body_value' => '"comment__comment_body"."comment_body_value"', 'comment__comment_body.comment_body_format' => '"comment__comment_body"."comment_body_format"', 'node_field_data.status' => '"node_field_data"."status"', 'node_field_data.created' => '"node_field_data"."created"', 'node_field_data.nid' => '"node_field_data"."nid"', 'node_field_data_created' => '"node_field_data_created"', 'bundle' => '"bundle"', 'uuid' => '"uuid"', 'prompt' => '"prompt"', 'operation_type' => '"operation_type"', 'provider' => '"provider"', 'model' => '"model"', 'output_text' => '"output_text"', 'configuration' => '"configuration"', 'extra_data' => '"extra_data"', 'tokens_input' => '"tokens_input"', 'tokens_output' => '"tokens_output"', 'tokens_total' => '"tokens_total"', 'tokens_reasoning' => '"tokens_reasoning"', 'tokens_cached' => '"tokens_cached"', 'response_text' => '"response_text"', 'entity_id' => '"entity_id"', 'revision_id' => '"revision_id"', 'delta' => '"delta"', 'langcode' => '"langcode"', 'tags_value' => '"tags_value"', 'base_table.uuid' => '"base_table"."uuid"', 'media_field_data.default_langcode' => '"media_field_data"."default_langcode"', 'base_table.vid' => '"base_table"."vid"', 'base_table.mid' => '"base_table"."mid"', 'base.mid' => '"base"."mid"', 'revision.vid' => '"revision"."vid"', 'revision.langcode' => '"revision"."langcode"', 'revision.revision_user' => '"revision"."revision_user"', 'revision.revision_created' => '"revision"."revision_created"', 'revision.revision_log_message' => '"revision"."revision_log_message"', 'revision.revision_default' => '"revision"."revision_default"', 'base.bundle' => '"base"."bundle"', '[media_field_data].[mid]' => '"media_field_data"."mid"', 'media_field_data.langcode' => '"media_field_data"."langcode"', 'media__field_media_image.field_media_image_target_id' => '"media__field_media_image"."field_media_image_target_id"', 'media__field_media_image.field_media_image_alt' => '"media__field_media_image"."field_media_image_alt"', 'media__field_media_image.field_media_image_title' => '"media__field_media_image"."field_media_image_title"', 'media__field_media_image.field_media_image_width' => '"media__field_media_image"."field_media_image_width"', 'media__field_media_image.field_media_image_height' => '"media__field_media_image"."field_media_image_height"', 'base.fid' => '"base"."fid"', 'base.uid' => '"base"."uid"', 'base.filename' => '"base"."filename"', 'base.uri' => '"base"."uri"', 'base.filemime' => '"base"."filemime"', 'base.filesize' => '"base"."filesize"', 'base.status' => '"base"."status"', 'base.created' => '"base"."created"', 'base.changed' => '"base"."changed"', 'value' => '"value"', 'uri' => '"uri"', 'nid' => '"nid"', 'n.created' => '"n"."created"', 'route_name' => '"route_name"', 'route_param_key' => '"route_param_key"', 'menu_name' => '"menu_name"', 'menu_tree.menu_name' => '"menu_tree"."menu_name"', 'menu_tree.route_name' => '"menu_tree"."route_name"', 'menu_tree.route_parameters' => '"menu_tree"."route_parameters"', 'menu_tree.url' => '"menu_tree"."url"', 'menu_tree.title' => '"menu_tree"."title"', 'menu_tree.description' => '"menu_tree"."description"', 'menu_tree.parent' => '"menu_tree"."parent"', 'menu_tree.weight' => '"menu_tree"."weight"', 'menu_tree.options' => '"menu_tree"."options"', 'menu_tree.expanded' => '"menu_tree"."expanded"', 'menu_tree.enabled' => '"menu_tree"."enabled"', 'menu_tree.provider' => '"menu_tree"."provider"', 'menu_tree.metadata' => '"menu_tree"."metadata"', 'menu_tree.class' => '"menu_tree"."class"', 'menu_tree.form_class' => '"menu_tree"."form_class"', 'menu_tree.id' => '"menu_tree"."id"', 'depth' => '"depth"', 'weight' => '"weight"', 'id' => '"id"', 'base_table.nid' => '"base_table"."nid"', 'subquery_base_table.nid' => '"subquery_base_table"."nid"', 'module' => '"module"', 'uid' => '"uid"', 'expanded' => '"expanded"', 'has_children' => '"has_children"', 'enabled' => '"enabled"', 'parent' => '"parent"', 'tag' => '"tag"', 'type' => '"type"', 'message' => '"message"', 'variables' => '"variables"', ...]; protected $escapedAliases = ['name' => '"name"', 'config' => '"config"', 'id' => '"id"', 'path' => '"path"', 'alias' => '"alias"', 'langcode' => '"langcode"', 'base_table' => '"base_table"', 'nid' => '"nid"', 'viewed' => '"viewed"', 'v' => '"v"', 'expression' => '"expression"', 'c' => '"c"', 'cid' => '"cid"', 'thread_order' => '"thread_order"', 'comment_type' => '"comment_type"', 'uuid' => '"uuid"', 'base' => '"base"', 'comment_field_data' => '"comment_field_data"', 'comment_field_data__langcode' => '"comment_field_data__langcode"', 'comment_body_value' => '"comment_body_value"', 'comment_body_format' => '"comment_body_format"', 'comment__comment_body' => '"comment__comment_body"', 'node_field_data_created' => '"node_field_data_created"', 'node_field_data' => '"node_field_data"', 'node__field_articles' => '"node__field_articles"', 'vid' => '"vid"', 'mid' => '"mid"', 'media_field_data' => '"media_field_data"', 'revision_user' => '"revision_user"', 'revision_created' => '"revision_created"', 'revision_log_message' => '"revision_log_message"', 'revision_default' => '"revision_default"', 'bundle' => '"bundle"', 'isDefaultRevision' => '"isDefaultRevision"', 'revision' => '"revision"', 'media_field_data__langcode' => '"media_field_data__langcode"', 'field_media_image_target_id' => '"field_media_image_target_id"', 'field_media_image_alt' => '"field_media_image_alt"', 'field_media_image_title' => '"field_media_image_title"', 'field_media_image_width' => '"field_media_image_width"', 'field_media_image_height' => '"field_media_image_height"', 'media__field_media_image' => '"media__field_media_image"', 'fid' => '"fid"', 'uid' => '"uid"', 'filename' => '"filename"', 'uri' => '"uri"', 'filemime' => '"filemime"', 'filesize' => '"filesize"', 'status' => '"status"', 'created' => '"created"', 'changed' => '"changed"', 's' => '"s"', 'n' => '"n"', 'menu_name' => '"menu_name"', 'route_name' => '"route_name"', 'route_parameters' => '"route_parameters"', 'url' => '"url"', 'title' => '"title"', 'description' => '"description"', 'parent' => '"parent"', 'weight' => '"weight"', 'options' => '"options"', 'expanded' => '"expanded"', 'enabled' => '"enabled"', 'provider' => '"provider"', 'metadata' => '"metadata"', 'class' => '"class"', 'form_class' => '"form_class"', 'menu_tree' => '"menu_tree"', 'maximum_revision_id' => '"maximum_revision_id"', 'subquery_base_table' => '"subquery_base_table"', 'sq_base_table' => '"sq_base_table"', 'ud' => '"ud"', 'cachetags' => '"cachetags"']; protected $identifierQuotes = [0 => '"', 1 => '"']; private array ${Drupal\Core\Database\Connection}enabledEvents = []; protected Drupal\Core\Database\Transaction\TransactionManagerInterface $transactionManager = class Drupal\mysql\Driver\Database\mysql\TransactionManager { private ?string ${Drupal\Core\Database\Transaction\TransactionManagerBase}rootId = '96eabbab1a06549884e97ca9'; private array ${Drupal\Core\Database\Transaction\TransactionManagerBase}stack = [...]; private array ${Drupal\Core\Database\Transaction\TransactionManagerBase}voidedItems = [...]; private array ${Drupal\Core\Database\Transaction\TransactionManagerBase}postTransactionCallbacks = [...]; private Drupal\Core\Database\Transaction\ClientConnectionTransactionState ${Drupal\Core\Database\Transaction\TransactionManagerBase}connectionTransactionState = enum Drupal\Core\Database\Transaction\ClientConnectionTransactionState::Committed; public bool $triggerWarningWhenUnpilingOnVoidTransaction = FALSE; protected readonly Drupal\Core\Database\Connection $connection = ... }; private $serverVersion = NULL }, $clientConnection = NULL, $query = 'SELECT "cid", "data", "created", "expire", "serialized", "tags", "checksum" FROM "cache_config" WHERE "cid" IN ( :cids__0 ) ORDER BY "cid"', $options = [], $rowCountEnabled = FALSE ).../Connection.php:441