arangod> db._executeTransaction({
  collections: { },
  action: "function (params) { return params[1]; }",
  params: [ 1, 2, 3 ]
});



arangod> db._executeTransaction({
  collections: { 
    write: "users",
    read: [ "c1", "c2" ]
  },
  action: "function (params) { var db = require('internal').db; var doc = db.c1.document(params['c1Key']); db.users.save(doc); doc = db.c2.document(params['c2Key']); db.users.save(doc);}",
  params: {
    c1Key: "user1",
    c2Key: "user2"
  }
});