check _db for NULL

diff --git a/zmd/backend/dbsource/DbAccess.cc b/zmd/backend/dbsource/DbAccess.cc
index 78f3d46..fdc9f24 100644 (file)
--- a/zmd/backend/dbsource/DbAccess.cc
+++ b/zmd/backend/dbsource/DbAccess.cc
@@ -401,7 +401,8 @@ DbAccess::openDb( bool for_writing )
     }
 
     int rc = sqlite3_open (_dbfile.c_str(), &_db);
-    if (rc != SQLITE_OK) {
+    if (rc != SQLITE_OK
+       || _db == NULL) {
        ERR << "Can not open SQL database: " << sqlite3_errmsg (_db) << endl;
        return false;
     }