[ZBXNEXT-435] Add Oracle TNSNAMES connect support (https://support.zabbix.com/browse/ZBXNEXT-435)
--- frontends/php/include/db.inc.php.orig	2019-06-27 08:00:56.526205359 +0300
+++ frontends/php/include/db.inc.php	2019-06-27 08:07:56.811265040 +0300
@@ -113,6 +113,8 @@
 					if ($DB['DATABASE']) {
 						$connect .= '/'.$DB['DATABASE'];
 					}
+				} else {
+					$connect = $DB['DATABASE'];
 				}
 
 				$DB['DB'] = @oci_connect($DB['USER'], $DB['PASSWORD'], $connect, 'UTF8');
--- src/libs/zbxdb/db.c.orig	2019-06-27 08:08:12.444044037 +0300
+++ src/libs/zbxdb/db.c	2019-06-27 08:11:40.680099796 +0300
@@ -443,16 +443,20 @@
 
 	zbx_vector_ptr_create(&oracle.db_results);
 
-	/* connection string format: [//]host[:port][/service name] */
-
-	if ('\0' != *host)
+	if (NULL != host && '\0' != *host)
 	{
+		/* connection string format: [//]host[:port][/service name] */
 		connect = zbx_strdcatf(connect, "//%s", host);
 		if (0 != port)
 			connect = zbx_strdcatf(connect, ":%d", port);
 		if (NULL != dbname && '\0' != *dbname)
 			connect = zbx_strdcatf(connect, "/%s", dbname);
 	}
+	else if (NULL != dbname && '\0' != *dbname)
+	{
+		/* use tnsname */
+		connect = strdup(dbname);
+	}
 	else
 		ret = ZBX_DB_FAIL;