Tips and tricks


If there is a large number of values in the database, the TIMERANGE() function method is recommended for querying small time intervals. After the SELECT method, first the entire database is read out and then all the values except the ones in question are rejected again. This takes unnecessary time.

Not advisable

Since, as mentioned above, the current and archived data is saved separately, there are some formats that do not make sense:

  • SELECT '_alert_hdl.._value'

  • SELECT ALERT '_online.._value'

  • dpQueryConnect...('_alert_hdl')


Querying data point details or attributes must be carried out carefully. So _u_range, for example, can only be queried (e.g. min/max), id specified in the data point detail:

SELECT '_online.._value', '_u_range.1.max' FROM '{test1,test2}'

No correct query without the detail number !