diff --git a/src/Ampersand/Plugs/MysqlDB/MysqlDB.php b/src/Ampersand/Plugs/MysqlDB/MysqlDB.php
index 6ef2ff752..62a201b7f 100644
--- a/src/Ampersand/Plugs/MysqlDB/MysqlDB.php
+++ b/src/Ampersand/Plugs/MysqlDB/MysqlDB.php
@@ -45,32 +45,32 @@ class MysqlDB implements ConceptPlugInterface, RelationPlugInterface, IfcPlugInt
      * Logger
      */
     private LoggerInterface $logger;
-    
+
     /**
      * A connection to the mysql database
      */
     protected \mysqli $dbLink;
-    
+
     /**
      * Host/server of mysql database
      */
     protected string $dbHost;
-    
+
     /**
      * Username for mysql database
      */
     protected string $dbUser;
-    
+
     /**
      * Password for mysql database
      */
     protected string $dbPass;
-    
+
     /**
      * Database name
      */
     protected string $dbName;
-    
+
     /**
      * Specifies if database transaction is active
      */
@@ -100,7 +100,7 @@ class MysqlDB implements ConceptPlugInterface, RelationPlugInterface, IfcPlugInt
      * Attribute is reset to 0 on start of (new) transaction
      */
     protected int $queryCount = 0;
-    
+
     /**
      * Constructor
      *
@@ -118,18 +118,18 @@ public function __construct(string $dbHost, string $dbUser, string $dbPass, stri
 
         $this->debugMode = $debugMode;
         $this->productionMode = $productionMode;
-        
+
         try {
             // Enable mysqli errors to be thrown as Exceptions
             mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
-            
+
             // Connect to MYSQL database
             $this->dbLink = mysqli_init();
-            
+
             // Flag MYSQLI_CLIENT_FOUND_ROWS -> https://www.codepuppet.com/2014/02/16/mysql-affected-rows-vs-rows-matched/
             $this->dbLink->real_connect($this->dbHost, $this->dbUser, $this->dbPass, '', 0, '', MYSQLI_CLIENT_FOUND_ROWS);
             $this->dbLink->set_charset("utf8mb4");
-            
+
             // Set sql_mode to ANSI
             $this->dbLink->query("SET SESSION sql_mode = 'ANSI,TRADITIONAL'");
         } catch (Exception $e) {
@@ -156,7 +156,7 @@ protected function selectDB(): void
             }
         }
     }
-    
+
     /**
      * Function to create new database. Drops database (and loose all data) if already exists
      */
@@ -165,7 +165,7 @@ protected function createDB(): void
         // Drop database
         $this->logger->info("Drop database if exists: '{$this->dbName}'");
         $this->doQuery("DROP DATABASE IF EXISTS {$this->dbName}");
-        
+
         // Create new database
         $this->logger->info("Create new database: '{$this->dbName}'");
         $this->doQuery("CREATE DATABASE {$this->dbName} DEFAULT CHARACTER SET UTF8MB4 COLLATE UTF8MB4_NOPAD_BIN");
@@ -203,7 +203,7 @@ public function getInstalledModelHash(): string
 
         return current($result)['checksum'];
     }
-    
+
     /**
      * Return escaped mysql representation of Atom (identifier) according to Ampersand technical types (TTypes)
      *
@@ -214,7 +214,7 @@ protected function getDBRepresentation(Atom $atom): mixed
         if (is_null($atom->getId())) {
             throw new InvalidOptionException("Atom identifier MUST NOT be NULL");
         }
-        
+
         switch ($atom->concept->type) {
             case TType::ALPHANUMERIC:
             case TType::BIGALPHANUMERIC:
@@ -251,7 +251,7 @@ protected function getDBRepresentation(Atom $atom): mixed
                 throw new MetaModelException("Unknown/unsupported ttype '{$atom->concept->type->value}' for concept '[{$atom->concept}]'");
         }
     }
-    
+
     /**
      * Execute query on database. Function replaces reserved words by their corresponding value (e.g. _SESSION)
      *
@@ -270,7 +270,7 @@ public function execute(string $query): bool|array
         } elseif ($result === true) {
             return true;
         }
-        
+
         $arr = [];
         while ($row = mysqli_fetch_assoc($result)) {
             $arr[] = $row;
@@ -288,7 +288,7 @@ public function prepare(string $query): \mysqli_stmt
 
         return $statement;
     }
-    
+
     /**
      * Execute query on database.
      * Set multiQuery if query is a single command or multiple commands concatenated by a semicolon
@@ -298,7 +298,7 @@ protected function doQuery(string $query, bool $multiQuery = false): mixed
         $this->lastQuery = $query;
         try {
             $this->queryCount++; // multi queries are counted as 1
-            
+
             if ($multiQuery) {
                 // MYSQLI_REPORT_STRICT mode doesn't throw Exceptions for multi_query execution,
                 // therefore we throw exceptions
@@ -342,7 +342,7 @@ protected function doQuery(string $query, bool $multiQuery = false): mixed
             }
         }
     }
-    
+
     /**
      * Escape identifier for use in database queries
      *
@@ -358,12 +358,12 @@ public function escape(string $escapestr): ?string
         }
     }
 
-/**************************************************************************************************
- *
- * Implementation of StorageInterface methods (incl. database transaction handling)
- *
- *************************************************************************************************/
-    
+    /**************************************************************************************************
+     *
+     * Implementation of StorageInterface methods (incl. database transaction handling)
+     *
+     *************************************************************************************************/
+
     /**
      * Returns name of storage implementation
      */
@@ -371,7 +371,7 @@ public function getLabel(): string
     {
         return "MySQL database {$this->dbHost} - {$this->dbName}";
     }
-    
+
     /**
      * Function to start/open a database transaction to track of all changes and be able to rollback
      */
@@ -384,7 +384,7 @@ public function startTransaction(Transaction $transaction): void
             $this->dbTransactionActive = true; // set flag dbTransactionActive
         }
     }
-    
+
     /**
      * Function to commit the open database transaction
      */
@@ -395,7 +395,7 @@ public function commitTransaction(Transaction $transaction): void
         $this->dbTransactionActive = false;
         $this->logger->info("{$this->queryCount} queries executed in this transaction");
     }
-    
+
     /**
      * Function to rollback changes made in the open database transaction
      */
@@ -406,32 +406,32 @@ public function rollbackTransaction(Transaction $transaction): void
         $this->dbTransactionActive = false;
         $this->logger->info("{$this->queryCount} queries executed in this transaction");
     }
-    
-/**************************************************************************************************
- *
- * Implementation of ConceptPlugInterface methods
- *
- *************************************************************************************************/
+
+    /**************************************************************************************************
+     *
+     * Implementation of ConceptPlugInterface methods
+     *
+     *************************************************************************************************/
 
     /**
-    * Check if atom exists in database
-    */
+     * Check if atom exists in database
+     */
     public function atomExists(Atom $atom): bool
     {
         $tableInfo = $atom->concept->getConceptTableInfo();
         $firstCol = current($tableInfo->getCols());
         $atomId = $this->getDBRepresentation($atom);
-        
+
         $query = "SELECT \"{$firstCol->getName()}\" FROM \"{$tableInfo->getName()}\" WHERE \"{$firstCol->getName()}\" = '{$atomId}'";
         $result = $this->execute($query);
-        
+
         if (empty($result)) {
             return false;
         } else {
             return true;
         }
     }
-    
+
     /**
      * Get all atoms for given concept
      *
@@ -440,7 +440,7 @@ public function atomExists(Atom $atom): bool
     public function getAllAtoms(Concept $concept): array
     {
         $tableInfo = $concept->getConceptTableInfo();
-        
+
         // Query all atoms in table
         if (isset($tableInfo->allAtomsQuery)) {
             $query = $tableInfo->allAtomsQuery;
@@ -448,7 +448,7 @@ public function getAllAtoms(Concept $concept): array
             $firstCol = current($tableInfo->getCols()); // We can query an arbitrary concept col for checking the existence of an atom
             $query = "SELECT DISTINCT \"{$firstCol->getName()}\" as \"atomId\" FROM \"{$tableInfo->getName()}\" WHERE \"{$firstCol->getName()}\" IS NOT NULL";
         }
-        
+
         $arr = [];
         foreach ((array)$this->execute($query) as $row) {
             $tgtAtom = new Atom($row['atomId'], $concept);
@@ -457,79 +457,79 @@ public function getAllAtoms(Concept $concept): array
         }
         return $arr;
     }
-    
+
     /**
      * Add atom to database
      */
     public function addAtom(Atom $atom): void
     {
         $atomId = $this->getDBRepresentation($atom);
-                        
+
         // Get table properties
         $conceptTableInfo = $atom->concept->getConceptTableInfo();
         $conceptTable = $conceptTableInfo->getName();
         $conceptCols = $conceptTableInfo->getCols(); // Concept are registered in multiple cols in case of specializations. We insert the new atom in every column.
-        
+
         // Create query string: "<col1>", "<col2>", etc
         $allConceptCols = '"' . implode('", "', $conceptTableInfo->getColNames()) . '"';
-        
-        
+
+
         // Create query string: '<newAtom>', '<newAtom', etc
         $atomIdsArray = array_fill(0, count($conceptCols), $atomId);
-        $allValues = "'".implode("', '", $atomIdsArray)."'";
-        
+        $allValues = "'" . implode("', '", $atomIdsArray) . "'";
+
         $str = '';
         foreach ($conceptCols as $col) {
             $str .= ", \"{$col->getName()}\" = '{$atomId}'";
         }
         $duplicateStatement = substr($str, 1);
-        
+
         $this->execute("INSERT INTO \"$conceptTable\" ($allConceptCols) VALUES ($allValues)"
-                  ." ON DUPLICATE KEY UPDATE $duplicateStatement");
-        
+            . " ON DUPLICATE KEY UPDATE $duplicateStatement");
+
         // Check if query resulted in an affected row
         $this->checkForAffectedRows();
     }
-    
+
     /**
      * Removing an atom as member from a concept set
      */
     public function removeAtom(Atom $atom): void
     {
         $atomId = $this->getDBRepresentation($atom);
-        
+
         // Get table and col for WHERE clause
         $conceptTable = $atom->concept->getConceptTableInfo();
         $conceptCol = $atom->concept->getConceptTableInfo()->getFirstCol();
-        
+
         // Get cols for UPDATE clause
         $colNames = [];
         $colNames[] = $conceptCol->getName(); // also update the concept col itself
         foreach ($atom->concept->getSpecializations() as $specConcept) {
             $colNames[] = $specConcept->getConceptTableInfo()->getFirstCol()->getName();
         }
-        
+
         // Create query string: "<col1>" = '<atom>', "<col2>" = '<atom>', etc
         $queryString = "\"" . implode("\" = NULL, \"", $colNames) . "\" = NULL";
-        
+
         $this->execute("UPDATE \"{$conceptTable->getName()}\" SET $queryString WHERE \"{$conceptCol->getName()}\" = '{$atomId}'");
-        
+
         // Check if query resulted in an affected row
         $this->checkForAffectedRows();
     }
-    
+
     /**
      * Delete atom from concept table in the database
      */
     public function deleteAtom(Atom $atom): void
     {
         $atomId = $this->getDBRepresentation($atom);
-        
+
         // Delete atom from concept table
         $conceptTable = $atom->concept->getConceptTableInfo();
         $query = "DELETE FROM \"{$conceptTable->getName()}\" WHERE \"{$conceptTable->getFirstCol()->getName()}\" = '{$atomId}' LIMIT 1";
         $this->execute($query);
-        
+
         // Check if query resulted in an affected row
         $this->checkForAffectedRows();
     }
@@ -538,44 +538,44 @@ public function executeCustomSQLQuery(string $query): bool|array
     {
         return $this->execute($query);
     }
-    
-/**************************************************************************************************
- *
- * Implementation of RelationPlugInterface methods
- *
- *************************************************************************************************/
-    
+
+    /**************************************************************************************************
+     *
+     * Implementation of RelationPlugInterface methods
+     *
+     *************************************************************************************************/
+
     /**
-    * Check if link exists in database
-    */
+     * Check if link exists in database
+     */
     public function linkExists(Link $link): bool
     {
         $relTable = $link->relation()->getMysqlTable();
         $srcAtomId = $this->getDBRepresentation($link->src());
         $tgtAtomId = $this->getDBRepresentation($link->tgt());
-        
+
         $result = $this->execute("SELECT * FROM \"{$relTable->getName()}\" WHERE \"{$relTable->srcCol()->getName()}\" = '{$srcAtomId}' AND \"{$relTable->tgtCol()->getName()}\" = '{$tgtAtomId}'");
-        
+
         if (empty($result)) {
             return false;
         } else {
             return true;
         }
     }
-    
+
     /**
-    * Get all links given a relation
-    *
-    * If src and/or tgt atom is specified only links are returned with these atoms
-    * @return \Ampersand\Core\Link[]
-    */
+     * Get all links given a relation
+     *
+     * If src and/or tgt atom is specified only links are returned with these atoms
+     * @return \Ampersand\Core\Link[]
+     */
     public function getAllLinks(Relation $relation, ?Atom $srcAtom = null, ?Atom $tgtAtom = null): array
     {
         $relTable = $relation->getMysqlTable();
-        
+
         // Query all atoms in table
         $query = "SELECT \"{$relTable->srcCol()->getName()}\" as \"src\", \"{$relTable->tgtCol()->getName()}\" as \"tgt\" FROM \"{$relTable->getName()}\"";
-        
+
         // Construct WHERE-clause if applicable
         if (isset($srcAtom)) {
             $query .= " WHERE \"{$relTable->srcCol()->getName()}\" = '{$this->getDBRepresentation($srcAtom)}'";
@@ -588,15 +588,15 @@ public function getAllLinks(Relation $relation, ?Atom $srcAtom = null, ?Atom $tg
         } else {
             $query .= " AND \"{$relTable->tgtCol()->getName()}\" IS NOT NULL";
         }
-        
+
         $links = [];
         foreach ((array)$this->execute($query) as $row) {
             $links[] = new Link($relation, new Atom($row['src'], $relation->srcConcept), new Atom($row['tgt'], $relation->tgtConcept));
         }
-        
+
         return $links;
     }
-    
+
     /**
      * Add link (srcAtom,tgtAtom) into database table for relation r
      */
@@ -605,12 +605,12 @@ public function addLink(Link $link): void
         $relation = $link->relation();
         $srcAtomId = $this->getDBRepresentation($link->src());
         $tgtAtomId = $this->getDBRepresentation($link->tgt());
-        
+
         $relTable = $relation->getMysqlTable();
         $table = $relTable->getName();
         $srcCol = $relTable->srcCol()->getName();
         $tgtCol = $relTable->tgtCol()->getName();
-        
+
         switch ($relTable->inTableOf()) {
             case TableType::Binary: // Relation is administrated in n-n table
                 $this->execute("REPLACE INTO \"{$table}\" (\"{$srcCol}\", \"{$tgtCol}\") VALUES ('{$srcAtomId}', '{$tgtAtomId}')");
@@ -624,11 +624,11 @@ public function addLink(Link $link): void
             default:
                 throw new FatalException("Unsupported TableType '{$relTable->inTableOf()->value}' to addLink for for relation '{$relation}'");
         }
-        
+
         // Check if query resulted in an affected row
         $this->checkForAffectedRows();
     }
-    
+
     /**
      * Delete link (srcAtom,tgtAtom) into database table for relation r
      */
@@ -637,12 +637,12 @@ public function deleteLink(Link $link): void
         $relation = $link->relation();
         $srcAtomId = $this->getDBRepresentation($link->src());
         $tgtAtomId = $this->getDBRepresentation($link->tgt());
-         
+
         $relTable = $relation->getMysqlTable();
         $table = $relTable->getName();
         $srcCol = $relTable->srcCol()->getName();
         $tgtCol = $relTable->tgtCol()->getName();
-         
+
         switch ($relTable->inTableOf()) {
             case TableType::Binary: // Relation is administrated in n-n table
                 $this->execute("DELETE FROM \"{$table}\" WHERE \"{$srcCol}\" = '{$srcAtomId}' AND \"{$tgtCol}\" = '{$tgtAtomId}'");
@@ -664,10 +664,10 @@ public function deleteLink(Link $link): void
             default:
                 throw new FatalException("Unsupported TableType '{$relTable->inTableOf()->value}' to deleteLink for for relation '{$relation}'");
         }
-        
+
         $this->checkForAffectedRows(); // Check if query resulted in an affected row
     }
-    
+
     /**
      * Undocumented function
      *
@@ -679,7 +679,7 @@ public function deleteAllLinks(Relation $relation, Atom $atom, SrcOrTgt $srcOrTg
     {
         $relationTable = $relation->getMysqlTable();
         $atomId = $this->getDBRepresentation($atom);
-        
+
         $whereCol = match ($srcOrTgt) {
             SrcOrTgt::SRC => $relationTable->srcCol(),
             SrcOrTgt::TGT => $relationTable->tgtCol()
@@ -700,7 +700,7 @@ public function deleteAllLinks(Relation $relation, Atom $atom, SrcOrTgt $srcOrTg
             default:
                 throw new FatalException("Unsupported TableType '{$relationTable->inTableOf()->value}' to deleteAllLinks for for relation '{$relation}'");
         }
-        
+
         $this->execute($query);
     }
 
@@ -710,8 +710,9 @@ public function deleteAllLinks(Relation $relation, Atom $atom, SrcOrTgt $srcOrTg
     public function emptyRelation(Relation $relation): void
     {
         $relationTable = $relation->getMysqlTable();
+        $tableOf = $relationTable->inTableOf()->value;
 
-        switch ($relationTable->inTableOf()) {
+        switch ($tableOf) {
             case null: // If n-n table, remove all rows
                 $this->execute("DELETE FROM \"{$relationTable->getName()}\"");
                 break;
@@ -721,17 +722,20 @@ public function emptyRelation(Relation $relation): void
             case 'tgt': // If in table of tgt concept, set src col to null
                 $this->execute("UPDATE \"{$relationTable->getName()}\" SET \"{$relationTable->srcCol()->getName()}\" = NULL");
                 break;
+            case 'binary': // If n-n table, remove all rows
+                $this->execute("DELETE FROM \"{$relationTable->getName()}\"");
+                break;
             default:
-                throw new FatalException("Unknown 'tableOf' option for relation '{$relation}'");
+                throw new FatalException("Unknown 'tableOf' option '{$tableOf}' for relation '{$relation}'");
         }
     }
-    
-/**************************************************************************************************
- *
- * Implementation of PlugInterface methods
- *
- *************************************************************************************************/
-    
+
+    /**************************************************************************************************
+     *
+     * Implementation of PlugInterface methods
+     *
+     *************************************************************************************************/
+
     /**
      * Execute query for given interface expression and source atom
      */
@@ -747,7 +751,7 @@ public function executeIfcExpression(InterfaceExprObject $ifc, Atom $srcAtom): m
         }
         return $this->execute($query);
     }
-    
+
     /**
      * Execute query for giver view segement and source atom
      */
@@ -755,22 +759,22 @@ public function executeViewExpression(ViewSegment $view, Atom $srcAtom): array
     {
         $srcAtomId = $this->getDBRepresentation($srcAtom);
         $viewSQL = $view->getQuery();
-        
+
         if (strpos($viewSQL, '_SRCATOM') !== false) {
             $query = str_replace('_SRCATOM', $srcAtomId, $viewSQL);
         } else {
             $query = "SELECT DISTINCT \"tgt\" FROM ({$viewSQL}) AS \"results\" WHERE \"src\" = '{$srcAtomId}' AND \"tgt\" IS NOT NULL";
         }
-        
+
         return array_column((array) $this->execute($query), 'tgt');
     }
-    
-/**************************************************************************************************
- *
- * Helper functions
- *
- *************************************************************************************************/
-    
+
+    /**************************************************************************************************
+     *
+     * Helper functions
+     *
+     *************************************************************************************************/
+
     /**
      * Check if insert/update/delete function resulted in updated record(s)
      * If not, report warning (or throw exception) to indicate that something is going wrong