Yandex Maps API. How to track the appearance of objects on the map?

Question

SQL

The task is to make a loading bar for objects on the map. It doesn’t work, as I understand it, because of the promises built into the api. I could not find anything in the documentation, poke your nose, please. Maybe there is some event by which I can track the appearance of objects?

Answer 1

It was not he who wrote the DB, but the request must be made ...
test=# select * from t1
test-# ;
n | b
-------------+---------
help1,help2 | ololosh
help2,help3 | help5
help7,help6 | help5
(3 rows)
test=# select * from t1 where n LIKE'%help1%';
n | b
-------------+---------
help1,help2 | ololosh
(1 row)
test=#

Answer 2

Standard trash, suitable only for the basket.
Read about database normalization.