diff --git a/include/conversation.php b/include/conversation.php
index 6ef2e73aa..5d013014b 100644
--- a/include/conversation.php
+++ b/include/conversation.php
@@ -110,14 +110,21 @@ function item_redir_and_replace_images($body, $images, $cid) {
 /**
  * Render actions localized
  */
-function localize_item(&$item) {
-
+function localize_item(&$item)
+{
 	$extracted = item_extract_images($item['body']);
 	if ($extracted['images']) {
 		$item['body'] = item_redir_and_replace_images($extracted['body'], $extracted['images'], $item['contact-id']);
 	}
 
-	/// @TODO Separted ???
+	/*
+	heluecht 2018-06-19: from my point of view this whole code part is useless.
+	It just renders the body message of technical posts (Like, dislike, ...).
+	But: The body isn't visible at all. So we do this stuff just because we can.
+	Even if these messages were visible, this would only mean that something went wrong.
+	During the further steps of the database restructuring I would like to address this issue.
+	*/
+
 	$xmlhead = "<" . "?xml version='1.0' encoding='UTF-8' ?" . ">";
 	if (activity_match($item['verb'], ACTIVITY_LIKE)
 		|| activity_match($item['verb'], ACTIVITY_DISLIKE)
@@ -125,15 +132,11 @@ function localize_item(&$item) {
 		|| activity_match($item['verb'], ACTIVITY_ATTENDNO)
 		|| activity_match($item['verb'], ACTIVITY_ATTENDMAYBE)) {
 
-		/// @TODO may hurt performance
-		$r = q("SELECT * FROM `item`, `contact`
-			WHERE `item`.`contact-id`=`contact`.`id`
-			AND `item`.`uri`='%s'",
-			dbesc($item['parent-uri']));
-		if (!DBM::is_result($r)) {
+		$fields = ['author-link', 'author-name', 'verb', 'object-type', 'resource-id', 'body', 'plink'];
+		$obj = Item::selectFirst($fields, ['uri' => $item['parent-uri']]);
+		if (!DBM::is_result($obj)) {
 			return;
 		}
-		$obj = $r[0];
 
 		$author  = '[url=' . $item['author-link'] . ']' . $item['author-name'] . '[/url]';
 		$objauthor =  '[url=' . $obj['author-link'] . ']' . $obj['author-name'] . '[/url]';
@@ -189,7 +192,8 @@ function localize_item(&$item) {
 		$links = XML::parseString($xmlhead."<links>".unxmlify($obj->link)."</links>");
 
 		$Bname = $obj->title;
-		$Blink = ""; $Bphoto = "";
+		$Blink = "";
+		$Bphoto = "";
 		foreach ($links->link as $l) {
 			$atts = $l->attributes();
 			switch ($atts['rel']) {
@@ -249,7 +253,7 @@ function localize_item(&$item) {
 
 		// now translate the verb
 		$poked_t = trim(sprintf($txt, "", ""));
-		$txt = str_replace( $poked_t, L10n::t($verb), $txt);
+		$txt = str_replace($poked_t, L10n::t($verb), $txt);
 
 		// then do the sprintf on the translation string
 
@@ -258,18 +262,12 @@ function localize_item(&$item) {
 	}
 
 	if (activity_match($item['verb'], ACTIVITY_TAG)) {
-		/// @TODO may hurt performance "joining" two tables + asterisk
-		$r = q("SELECT * FROM `item`, `contact`
-			WHERE `item`.`contact-id`=`contact`.`id`
-			AND `item`.`uri`='%s'",
-			dbesc($item['parent-uri']));
-
-		if (!DBM::is_result($r)) {
+		$fields = ['author-link', 'author-name', 'verb', 'object-type', 'resource-id', 'body', 'plink'];
+		$obj = Item::selectFirst($fields, ['uri' => $item['parent-uri']]);
+		if (!DBM::is_result($obj)) {
 			return;
 		}
 
-		$obj = $r[0];
-
 		$author  = '[url=' . Contact::magicLinkById($item['author-id']) . ']' . $item['author-name'] . '[/url]';
 		$objauthor =  '[url=' . Contact::magicLinkById($obj['author-id']) . ']' . $obj['author-name'] . '[/url]';
 
@@ -299,8 +297,7 @@ function localize_item(&$item) {
 		$parsedobj = XML::parseString($xmlhead.$item['object']);
 
 		$tag = sprintf('#[url=%s]%s[/url]', $parsedobj->id, $parsedobj->content);
-		$item['body'] = L10n::t('%1$s tagged %2$s\'s %3$s with %4$s', $author, $objauthor, $plink, $tag );
-
+		$item['body'] = L10n::t('%1$s tagged %2$s\'s %3$s with %4$s', $author, $objauthor, $plink, $tag);
 	}
 
 	if (activity_match($item['verb'], ACTIVITY_FAVORITE)) {
@@ -315,13 +312,9 @@ function localize_item(&$item) {
 
 		$obj = XML::parseString($xmlhead.$item['object']);
 		if (strlen($obj->id)) {
-			$r = q("SELECT * FROM `item` WHERE `uri` = '%s' AND `uid` = %d LIMIT 1",
-					dbesc($obj->id),
-					intval($item['uid'])
-			);
-
-			if (DBM::is_result($r) && $r[0]['plink']) {
-				$target = $r[0];
+			$fields = ['author-link', 'author-name', 'plink'];
+			$target = Item::selectFirst($fields, ['uri' => $obj->id, 'uid' => $item['uid']]);
+			if (DBM::is_result($target) && $target['plink']) {
 				$Bname = $target['author-name'];
 				$Blink = $target['author-link'];
 				$A = '[url=' . Contact::magicLink($Alink) . ']' . $Aname . '[/url]';
@@ -1009,7 +1002,7 @@ function format_like($cnt, array $arr, $type, $id) {
 		}
 		if ($total >= MAX_LIKERS) {
 			$str = implode(', ', $arr);
-			$str .= L10n::t('and %d other people', $total - MAX_LIKERS );
+			$str .= L10n::t('and %d other people', $total - MAX_LIKERS);
 		}
 
 		$likers = $str;
diff --git a/include/security.php b/include/security.php
index bcfddf887..e8a03ad0f 100644
--- a/include/security.php
+++ b/include/security.php
@@ -99,11 +99,9 @@ function authenticate_success($user_record, $login_initial = false, $interactive
 	$master_record = $a->user;
 
 	if ((x($_SESSION, 'submanage')) && intval($_SESSION['submanage'])) {
-		$r = dba::fetch_first("SELECT * FROM `user` WHERE `uid` = ? LIMIT 1",
-			intval($_SESSION['submanage'])
-		);
-		if (DBM::is_result($r)) {
-			$master_record = $r;
+		$user = dba::selectFirst('user', [], ['uid' => $_SESSION['submanage']]);
+		if (DBM::is_result($user)) {
+			$master_record = $user;
 		}
 	}
 
@@ -155,10 +153,10 @@ function authenticate_success($user_record, $login_initial = false, $interactive
 		logger('auth_identities refresh: ' . print_r($a->identities, true), LOGGER_DEBUG);
 	}
 
-	$r = dba::fetch_first("SELECT * FROM `contact` WHERE `uid` = ? AND `self` LIMIT 1", $_SESSION['uid']);
-	if (DBM::is_result($r)) {
-		$a->contact = $r;
-		$a->cid = $r['id'];
+	$contact = dba::selectFirst('contact', [], ['uid' => $_SESSION['uid'], 'self' => true]);
+	if (DBM::is_result($contact)) {
+		$a->contact = $contact;
+		$a->cid = $contact['id'];
 		$_SESSION['cid'] = $a->cid;
 	}
 
diff --git a/mod/item.php b/mod/item.php
index f164fb0ae..4c78af6ca 100644
--- a/mod/item.php
+++ b/mod/item.php
@@ -647,13 +647,13 @@ function item_post(App $a) {
 	// This field is for storing the raw conversation data
 	$datarray['protocol'] = PROTOCOL_DFRN;
 
-	$r = dba::fetch_first("SELECT `conversation-uri`, `conversation-href` FROM `conversation` WHERE `item-uri` = ?", $datarray['parent-uri']);
-	if (DBM::is_result($r)) {
+	$conversation = dba::selectFirst('conversation', ['conversation-uri', 'conversation-href'], ['item-uri' => $datarray['parent-uri']]);
+	if (DBM::is_result($conversation)) {
 		if ($r['conversation-uri'] != '') {
-			$datarray['conversation-uri'] = $r['conversation-uri'];
+			$datarray['conversation-uri'] = $conversation['conversation-uri'];
 		}
 		if ($r['conversation-href'] != '') {
-			$datarray['conversation-href'] = $r['conversation-href'];
+			$datarray['conversation-href'] = $conversation['conversation-href'];
 		}
 	}
 
diff --git a/mod/photos.php b/mod/photos.php
index 9cd348274..e823da59f 100644
--- a/mod/photos.php
+++ b/mod/photos.php
@@ -172,7 +172,7 @@ function photos_post(App $a)
 	}
 
 	if (!$can_post) {
-		notice(L10n::t('Permission denied.') . EOL );
+		notice(L10n::t('Permission denied.') . EOL);
 		killme();
 	}
 
@@ -275,7 +275,7 @@ function photos_post(App $a)
 			$str_res = implode(',', $res);
 
 			// remove the associated photos
-			q("DELETE FROM `photo` WHERE `resource-id` IN ( $str_res ) AND `uid` = %d",
+			q("DELETE FROM `photo` WHERE `resource-id` IN ($str_res) AND `uid` = %d",
 				intval($page_owner_uid)
 			);
 
@@ -372,7 +372,7 @@ function photos_post(App $a)
 			if (DBM::is_result($r)) {
 				$Image = new Image($r[0]['data'], $r[0]['type']);
 				if ($Image->isValid()) {
-					$rotate_deg = ( (intval($_POST['rotate']) == 1) ? 270 : 90 );
+					$rotate_deg = ((intval($_POST['rotate']) == 1) ? 270 : 90);
 					$Image->rotate($rotate_deg);
 
 					$width  = $Image->getWidth();
@@ -918,7 +918,7 @@ function photos_content(App $a)
 	require_once 'include/conversation.php';
 
 	if (!x($a->data,'user')) {
-		notice(L10n::t('No photos selected') . EOL );
+		notice(L10n::t('No photos selected') . EOL);
 		return;
 	}
 
@@ -1216,7 +1216,7 @@ function photos_content(App $a)
 			if (DBM::is_result($ph)) {
 				notice(L10n::t('Permission denied. Access to this item may be restricted.'));
 			} else {
-				notice(L10n::t('Photo not available') . EOL );
+				notice(L10n::t('Photo not available') . EOL);
 			}
 			return;
 		}
@@ -1289,15 +1289,15 @@ function photos_content(App $a)
 			];
 
 			// lock
-			$lock = ( ( ($ph[0]['uid'] == local_user()) && (strlen($ph[0]['allow_cid']) || strlen($ph[0]['allow_gid'])
-					|| strlen($ph[0]['deny_cid']) || strlen($ph[0]['deny_gid'])) )
+			$lock = ((($ph[0]['uid'] == local_user()) && (strlen($ph[0]['allow_cid']) || strlen($ph[0]['allow_gid'])
+					|| strlen($ph[0]['deny_cid']) || strlen($ph[0]['deny_gid'])))
 					? L10n::t('Private Message')
 					: Null);
 
 
 		}
 
-		if ( $cmd === 'edit') {
+		if ($cmd === 'edit') {
 			$tpl = get_markup_template('photo_edit_head.tpl');
 			$a->page['htmlhead'] .= replace_macros($tpl,[
 				'$prevlink' => $prevlink,
@@ -1332,7 +1332,8 @@ function photos_content(App $a)
 		// The difference is that we won't be displaying the conversation head item
 		// as a "post" but displaying instead the photo it is linked to
 
-		$linked_items = q("SELECT * FROM `item` WHERE `resource-id` = '%s' $sql_extra LIMIT 1",
+		/// @todo Rewrite this query. To do so, $sql_extra must be changed
+		$linked_items = q("SELECT `id` FROM `item` WHERE `resource-id` = '%s' $sql_extra LIMIT 1",
 			dbesc($datum)
 		);
 
@@ -1340,7 +1341,8 @@ function photos_content(App $a)
 		$link_item = [];
 
 		if (DBM::is_result($linked_items)) {
-			$link_item = $linked_items[0];
+			// This is a workaround to not being forced to rewrite the while $sql_extra handling
+			$link_item = Item::selectFirstForUser(local_user(), [], ['id' => $linked_items[0]['id']]);
 
 			$r = q("SELECT COUNT(*) AS `total`
 				FROM `item` LEFT JOIN `contact` ON `contact`.`id` = `item`.`contact-id`
diff --git a/src/Core/Worker.php b/src/Core/Worker.php
index 4659d2283..8960780e5 100644
--- a/src/Core/Worker.php
+++ b/src/Core/Worker.php
@@ -155,12 +155,7 @@ class Worker
 	 */
 	private static function totalEntries()
 	{
-		$s = dba::fetch_first("SELECT COUNT(*) AS `total` FROM `workerqueue` WHERE `executed` <= ? AND NOT `done`", NULL_DATE);
-		if (DBM::is_result($s)) {
-			return $s["total"];
-		} else {
-			return 0;
-		}
+		return dba::count('workerqueue', ["`executed` <= ? AND NOT `done`", NULL_DATE]);
 	}
 
 	/**
@@ -718,9 +713,7 @@ class Worker
 	 */
 	private static function activeWorkers()
 	{
-		$workers = dba::fetch_first("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'Worker.php'");
-
-		return $workers["processes"];
+		return dba::count('process', ['command' => 'Worker.php']);
 	}
 
 	/**
@@ -973,9 +966,9 @@ class Worker
 
 		self::clearProcesses();
 
-		$workers = dba::fetch_first("SELECT COUNT(*) AS `processes` FROM `process` WHERE `command` = 'worker.php'");
+		$workers = self::activeWorkers();
 
-		if ($workers["processes"] == 0) {
+		if ($workers == 0) {
 			self::callWorker();
 		}
 	}
diff --git a/src/Model/Conversation.php b/src/Model/Conversation.php
index cd51a537e..17f151fe0 100644
--- a/src/Model/Conversation.php
+++ b/src/Model/Conversation.php
@@ -52,8 +52,8 @@ class Conversation
 				$conversation['source'] = $arr['source'];
 			}
 
-			$old_conv = dba::fetch_first("SELECT `item-uri`, `reply-to-uri`, `conversation-uri`, `conversation-href`, `protocol`, `source`
-					FROM `conversation` WHERE `item-uri` = ?", $conversation['item-uri']);
+			$fields = ['item-uri', 'reply-to-uri', 'conversation-uri', 'conversation-href', 'protocol', 'source'];
+			$old_conv = dba::selectFirst('conversation', $fields, ['item-uri' => $conversation['item-uri']]);
 			if (DBM::is_result($old_conv)) {
 				// Don't update when only the source has changed.
 				// Only do this when there had been no source before.
diff --git a/src/Model/Item.php b/src/Model/Item.php
index c3b759f65..f448c6ba7 100644
--- a/src/Model/Item.php
+++ b/src/Model/Item.php
@@ -296,7 +296,7 @@ class Item extends BaseObject
 			'file', 'location', 'coord', 'allow_cid', 'allow_gid', 'deny_cid', 'deny_gid',
 			'private', 'pubmail', 'moderated', 'visible', 'starred', 'bookmark',
 			'unseen', 'deleted', 'origin', 'forum_mode', 'mention',
-			'rendered-hash', 'rendered-html', 'global', 'shadow', 'content-warning',
+			'rendered-hash', 'rendered-html', 'global', 'content-warning',
 			'id' => 'item_id', 'network'];
 
 		$fields['author'] = ['url' => 'author-link', 'name' => 'author-name',
@@ -306,7 +306,7 @@ class Item extends BaseObject
 			'thumb' => 'owner-avatar', 'nick' => 'owner-nick', 'network' => 'owner-network'];
 
 		$fields['contact'] = ['url' => 'contact-link', 'name' => 'contact-name', 'thumb' => 'contact-avatar',
-			'network', 'url', 'name', 'writable', 'self', 'id' => 'cid', 'alias', 'uid' => 'contact-uid',
+			'url', 'name', 'writable', 'self', 'id' => 'cid', 'alias', 'uid' => 'contact-uid',
 			'photo', 'name-date', 'uri-date', 'avatar-date', 'thumb', 'dfrn-id', 'network' => 'contact-network'];
 
 		$fields['parent-item'] = ['guid' => 'parent-guid', 'network' => 'parent-network'];
diff --git a/src/Model/User.php b/src/Model/User.php
index 76769e14c..6754f2207 100644
--- a/src/Model/User.php
+++ b/src/Model/User.php
@@ -211,18 +211,11 @@ class User
 					]
 				);
 			} else {
-				$user = dba::fetch_first('SELECT `uid`, `password`, `legacy_password`
-					FROM `user`
-					WHERE (`email` = ? OR `username` = ? OR `nickname` = ?)
-					AND `blocked` = 0
-					AND `account_expired` = 0
-					AND `account_removed` = 0
-					AND `verified` = 1
-					LIMIT 1',
-					$user_info,
-					$user_info,
-					$user_info
-				);
+				$fields = ['uid', 'password', 'legacy_password'];
+				$condition = ["(`email` = ? OR `username` = ? OR `nickname` = ?)
+					AND NOT `blocked` AND NOT `account_expired` AND NOT `account_removed` AND `verified`",
+					$user_info, $user_info, $user_info];
+				$user = dba::selectFirst('user', $fields, $condition);
 			}
 
 			if (!DBM::is_result($user)) {
diff --git a/src/Protocol/DFRN.php b/src/Protocol/DFRN.php
index 9a24c75e4..a9e836499 100644
--- a/src/Protocol/DFRN.php
+++ b/src/Protocol/DFRN.php
@@ -950,13 +950,13 @@ class DFRN
 		$conversation_uri = $conversation_href;
 
 		if (isset($parent_item)) {
-			$r = dba::fetch_first("SELECT `conversation-uri`, `conversation-href` FROM `conversation` WHERE `item-uri` = ?", $item['parent-uri']);
-			if (DBM::is_result($r)) {
+			$conversation = dba::selectFirst('conversation', ['conversation-uri', 'conversation-href'], ['item-uri' => $item['parent-uri']]);
+			if (DBM::is_result($conversation)) {
 				if ($r['conversation-uri'] != '') {
-					$conversation_uri = $r['conversation-uri'];
+					$conversation_uri = $conversation['conversation-uri'];
 				}
 				if ($r['conversation-href'] != '') {
-					$conversation_href = $r['conversation-href'];
+					$conversation_href = $conversation['conversation-href'];
 				}
 			}
 		}
@@ -1537,13 +1537,11 @@ class DFRN
 		$author["name"] = $xpath->evaluate($element."/atom:name/text()", $context)->item(0)->nodeValue;
 		$author["link"] = $xpath->evaluate($element."/atom:uri/text()", $context)->item(0)->nodeValue;
 
-		$contact_old = dba::fetch_first("SELECT `id`, `uid`, `url`, `network`, `avatar-date`, `avatar`, `name-date`, `uri-date`, `addr`,
-				`name`, `nick`, `about`, `location`, `keywords`, `xmpp`, `bdyear`, `bd`, `hidden`, `contact-type`
-				FROM `contact` WHERE `uid` = ? AND `nurl` = ? AND `network` != ?",
-			$importer["importer_uid"],
-			normalise_link($author["link"]),
-			NETWORK_STATUSNET
-		);
+		$fields = ['id', 'uid', 'url', 'network', 'avatar-date', 'avatar', 'name-date', 'uri-date', 'addr',
+			'name', 'nick', 'about', 'location', 'keywords', 'xmpp', 'bdyear', 'bd', 'hidden', 'contact-type'];
+		$condition = ["`uid` = ? AND `nurl` = ? AND `network` != ?",
+			$importer["importer_uid"], normalise_link($author["link"]), NETWORK_STATUSNET];
+		$contact_old = dba::selectFirst('contact', $fields, $condition);
 
 		if (DBM::is_result($contact_old)) {
 			$author["contact-id"] = $contact_old["id"];
diff --git a/src/Protocol/OStatus.php b/src/Protocol/OStatus.php
index e84dddcea..957f60a2c 100644
--- a/src/Protocol/OStatus.php
+++ b/src/Protocol/OStatus.php
@@ -1971,14 +1971,13 @@ class OStatus
 			$conversation_uri = $conversation_href;
 
 			if (isset($parent_item)) {
-				$r = dba::fetch_first("SELECT `conversation-uri`, `conversation-href` FROM `conversation` WHERE `item-uri` = ?", $parent_item);
-
-				if (DBM::is_result($r)) {
+				$conversation = dba::selectFirst('conversation', ['conversation-uri', 'conversation-href'], ['item-uri' => $parent_item]);
+				if (DBM::is_result($conversation)) {
 					if ($r['conversation-uri'] != '') {
-						$conversation_uri = $r['conversation-uri'];
+						$conversation_uri = $conversation['conversation-uri'];
 					}
 					if ($r['conversation-href'] != '') {
-						$conversation_href = $r['conversation-href'];
+						$conversation_href = $conversation['conversation-href'];
 					}
 				}
 			}