diff --git a/htdocs/core/db/mssql.class.php b/htdocs/core/db/mssql.class.php
index 1c9b8f97ba6..0be65dfe2e6 100644
--- a/htdocs/core/db/mssql.class.php
+++ b/htdocs/core/db/mssql.class.php
@@ -41,7 +41,7 @@ class DoliDBMssql extends DoliDB
 	var $forcecollate='latin1_swedish_ci';      // Can't be static as it may be forced with a dynamic value
 	//! Version min database
 	const VERSIONMIN='2000';
-	//! Resultset of last query
+	/** @var resource Resultset of last query */
 	private $_results;
 
     /**
diff --git a/htdocs/core/db/mysql.class.php b/htdocs/core/db/mysql.class.php
index 87f05dee7f6..30a7780afdf 100644
--- a/htdocs/core/db/mysql.class.php
+++ b/htdocs/core/db/mysql.class.php
@@ -37,7 +37,7 @@ class DoliDBMysql extends DoliDB
 	const LABEL='MySQL';
 	//! Version min database
 	const VERSIONMIN='4.1.0';
-	//! Resultset of last query
+	/** @var resource Resultset of last query */
 	private $_results;
 
 	/**
diff --git a/htdocs/core/db/mysqli.class.php b/htdocs/core/db/mysqli.class.php
index 0a46e70e2ba..591789fcd89 100644
--- a/htdocs/core/db/mysqli.class.php
+++ b/htdocs/core/db/mysqli.class.php
@@ -37,7 +37,7 @@ class DoliDBMysqli extends DoliDB
     const LABEL='MySQL';
     //! Version min database
     const VERSIONMIN='4.1.3';
-	//! Resultset of last query
+	/** @var mysqli_result Resultset of last query */
 	private $_results;
 
     /**
diff --git a/htdocs/core/db/pgsql.class.php b/htdocs/core/db/pgsql.class.php
index d4866daa1c2..0466c2ad96b 100644
--- a/htdocs/core/db/pgsql.class.php
+++ b/htdocs/core/db/pgsql.class.php
@@ -45,7 +45,7 @@ class DoliDBPgsql extends DoliDB
     var $forcecollate='';			// Can't be static as it may be forced with a dynamic value
 	//! Version min database
 	const VERSIONMIN='8.4.0';	// Version min database
-	//! Resultset of last query
+	/** @var resource Resultset of last query */
 	private $_results;
 
 	public $unescapeslashquot;
diff --git a/htdocs/core/db/sqlite.class.php b/htdocs/core/db/sqlite.class.php
index d4762da4e96..647cd3a6798 100644
--- a/htdocs/core/db/sqlite.class.php
+++ b/htdocs/core/db/sqlite.class.php
@@ -37,7 +37,7 @@ class DoliDBSqlite extends DoliDB
     const LABEL='PDO Sqlite';
     //! Version min database
     const VERSIONMIN='3.0.0';
-	//! Resultset of last query
+	/** @var PDOStatement Resultset of last query */
 	private $_results;
 
     /**
diff --git a/htdocs/core/db/sqlite3.class.php b/htdocs/core/db/sqlite3.class.php
index d40aed006dc..68d7ab672db 100644
--- a/htdocs/core/db/sqlite3.class.php
+++ b/htdocs/core/db/sqlite3.class.php
@@ -38,8 +38,8 @@ class DoliDBSqlite3 extends DoliDB
     const LABEL='Sqlite3';
     //! Version min database
     const VERSIONMIN='3.0.0';
-    //! Resultset of last query
-    private $_results;
+	/** @var SQLite3Result Resultset of last query */
+	private $_results;
 
     const WEEK_MONDAY_FIRST=1;
     const WEEK_YEAR = 2;