diff --git a/build/database/repo/formation.php b/build/database/repo/formation.php
index 6989427..875fda1 100644
--- a/build/database/repo/formation.php
+++ b/build/database/repo/formation.php
@@ -13,37 +13,84 @@ use database\core\Repo_i;
 
 class formation extends Repo_i {
 
-	public function create(string $label, bool $isInternal) : int{
-		$st = $this->pdo->prepare("INSERT INTO Formation (labelFormation, isInternal) VALUE (:label,:isInternal);");
+	/* (1) Creates a new formation
+	*
+	* @label<String>					The formation label
+	* @isInternal<bool>					Whether the formation is internal
+	*
+	* @return form_id<int>				The formation UID (or NULL on error)
+	*
+	---------------------------------------------------------*/
+	public function create(string $label, bool $isInternal) : ?int{
 
-		$st->execute([
-			"label" => $label,
-			"isInternal" => $isInternal? 1 : 0
+		/* (1) Prepare statement */
+		$st = $this->pdo->prepare("INSERT INTO `Formation` (`labelFormation`, `isInternal`) VALUE (:label, :isInternal);");
+
+		/* (2) Bind params and execute statement */
+		if( is_bool($st) ) return NULL;
+		$success = $st->execute([
+			':label'      => $label,
+			':isInternal' => $isInternal ? 1 : 0
 		]);
 
+		/* (3) Manage error */
+		if( !$success )
+			return NULL;
+
+		/* (4) Return inserted ID */
 		return $this->pdo->lastInsertId();
+
 	}
 
-	public function exists(string $label) : int{
-		$st = $this->pdo->prepare("SELECT idFormation FROM Formation WHERE labelFormation = :label");
 
-		$st->execute([
-			"label" => $label
-		]);
 
-		return $st->fetch()["idFormation"]?: 0;
+	/* (2) Check if a formation exists (by its label)
+	*
+	* @label<String>					The formation label
+	*
+	* @return form_id<int>				The formation UID (or NULL on error)
+	*
+	---------------------------------------------------------*/
+	public function exists(string $label) : ?int{
+
+		/* (1) Prepare statement */
+		$st = $this->pdo->prepare("SELECT `idFormation` FROM `Formation` WHERE `labelFormation` = :label");
+
+		/* (2) Bind params and execute statement */
+		if( is_bool($st) ) return NULL;
+		$success = $st->execute([ ':label' => $label ]);
+
+		/* (3) Manage error */
+		if( !$success )
+			return NULL;
+
+		/* (4) Return if we have a result */
+
+		return $st->fetch()['idFormation'] ?: 0;
+
 	}
 
+
+	/* (3) Deletes a formation
+	*
+	* @return deleted<bool>				Whether the formation have been deleeted successfully
+	*
+	---------------------------------------------------------*/
 	public function delete(int $id) : bool{
-		$st = $this->pdo->prepare("DELETE FROM Formation WHERE idFormation = :id");
 
-		return $st->execute([
-			"id" => $id
-		]);
+		/* (1) Prepare statement */
+		$st = $this->pdo->prepare("DELETE FROM `Formation` WHERE `idFormation` = :id");
+
+		/* (2) Bind params and execute request */
+		if( is_bool($st) ) return false;
+
+		/* (3) Dispatch the execution status */
+		return $st->execute([ ':id' => $id ]);
+
 	}
 
 
-	/* (x) Gets a formation by its ID || getAll
+	/* (4) Gets a formation by its ID || getAll
 	*
 	* @form_id<int>							[OPT] The formation id, if not set, getAll()
 	*
@@ -84,4 +131,44 @@ class formation extends Repo_i {
 
 	}
 
+
+	/* (5) Gets all professors who teaches a formation by ids (array)
+	*
+	* @form_id<int>							The formation id
+	*
+	* @return professors<array>				The professors' UID matching the @form_id formation
+	*
+	---------------------------------------------------------*/
+	public function getProfessors(int $form_id) : array{
+
+		/* (1) Prepare statement */
+		$st = $this->pdo->prepare("SELECT p.idProfesseur
+			FROM Professeur p, Formation f
+			WHERE (
+				   p.idProfesseur IN ( SELECT p_cr.idProfesseur FROM Professeur p_cr, UE ue, Cours c WHERE c.Professeur_idProfesseur = p_cr.idProfesseur AND c.UE_code = ue.code AND ue.Formation_idFormation = f.idFormation )
+				OR p.idProfesseur IN ( SELECT p_td.idProfesseur FROM Professeur p_td, UE ue, TD t WHERE t.Professeur_idProfesseur = p_td.idProfesseur    AND t.UE_code = ue.code AND ue.Formation_idFormation = f.idFormation )
+				OR p.idProfesseur IN ( SELECT p_tp.idProfesseur FROM Professeur p_tp, UE ue, TP t WHERE t.Professeur_idProfesseur = p_tp.idProfesseur    AND t.UE_code = ue.code AND ue.Formation_idFormation = f.idFormation )
+			)
+			AND f.idFormation = :form_id;");
+
+		/* (2) Bind params and execute statement */
+		if( is_bool($st) ) return [];
+		$success = $st->execute([ ':form_id' => $form_id ]);
+
+		/* (3) Manage error */
+		if( !$success )
+			return [];
+
+		/* (4) Get data */
+		$fetched = $st->fetchAll();
+
+		/* (5) Return [] on no result */
+		if( $fetched === false )
+			return [];
+
+		/* (6) Return data */
+		return $fetched;
+
+	}
+
 }
\ No newline at end of file