diff --git a/htdocs/product/inventory/class/inventory.class.php b/htdocs/product/inventory/class/inventory.class.php
index bb55bc1b143..f0157e52009 100644
--- a/htdocs/product/inventory/class/inventory.class.php
+++ b/htdocs/product/inventory/class/inventory.class.php
@@ -266,7 +266,7 @@ class Inventory extends CommonObject
 
 		if ($this->status == self::STATUS_DRAFT) {
 			// Delete inventory
-			$sql = 'DELETE FROM '.MAIN_DB_PREFIX.'inventorydet WHERE fk_inventory = '.((int) $this->id);
+			$sql = 'DELETE FROM '.$this->db->prefix().'inventorydet WHERE fk_inventory = '.((int) $this->id);
 			$resql = $this->db->query($sql);
 			if (!$resql) {
 				$this->error = $this->db->lasterror();
@@ -277,9 +277,9 @@ class Inventory extends CommonObject
 			// Scan existing stock to prefill the inventory
 			$sql = 'SELECT ps.rowid, ps.fk_entrepot as fk_warehouse, ps.fk_product, ps.reel,';
 			$sql .= ' pb.batch, pb.qty';
-			$sql .= ' FROM '.MAIN_DB_PREFIX.'product_stock as ps';
-			$sql .= ' LEFT JOIN '.MAIN_DB_PREFIX.'product_batch as pb ON pb.fk_product_stock = ps.rowid,';
-			$sql .= ' '.MAIN_DB_PREFIX.'product as p, '.MAIN_DB_PREFIX.'entrepot as e';
+			$sql .= ' FROM '.$this->db->prefix().'product_stock as ps';
+			$sql .= ' LEFT JOIN '.$this->db->prefix().'product_batch as pb ON pb.fk_product_stock = ps.rowid,';
+			$sql .= ' '.$this->db->prefix().'product as p, '.$this->db->prefix().'entrepot as e';
 			$sql .= ' WHERE p.entity IN ('.getEntity('product').')';
 			$sql .= ' AND ps.fk_product = p.rowid AND ps.fk_entrepot = e.rowid';
 			if (empty($conf->global->STOCK_SUPPORTS_SERVICES)) {
@@ -349,7 +349,7 @@ class Inventory extends CommonObject
 		$this->db->begin();
 
 		// Delete inventory
-		$sql = 'DELETE FROM '.MAIN_DB_PREFIX.'inventorydet WHERE fk_inventory = '.((int) $this->id);
+		$sql = 'DELETE FROM '.$this->db->prefix().'inventorydet WHERE fk_inventory = '.((int) $this->id);
 		$resql = $this->db->query($sql);
 		if (!$resql) {
 			$this->error = $this->db->lasterror();
@@ -642,7 +642,7 @@ class Inventory extends CommonObject
 	{
 		$sql = 'SELECT rowid, date_creation as datec, tms as datem, date_validation as datev,';
 		$sql .= ' fk_user_creat, fk_user_modif, fk_user_valid';
-		$sql .= ' FROM '.MAIN_DB_PREFIX.$this->table_element.' as t';
+		$sql .= ' FROM '.$this->db->prefix().$this->table_element.' as t';
 		$sql .= ' WHERE t.rowid = '.((int) $id);
 		$result = $this->db->query($sql);
 		if ($result) {