====SetInitialValue====

The **SetInitialValue** function sets the value of a specific data point //before the query range begins//.

It's part of the [[histhelper|HistoryFill]] class, and is used to provide boundary-filling functionality to ARDI drivers.

Industrial historians and high-quality time-series databases will often ensure that you get 'bounding values' around the time-range you request. For example, if you query data between 9:12 and 9:50, you'll get values at those times //even if there weren't recordings at those exact times//.

ARDI **expects** this behaviour from drivers, where possible. It's one of the reasons we suggest you avoid using relational databases for time-series information, as this step is time-consuming and computationally expensive.

For systems that don't natively extract boundary data in a single query, the **SetInitialValue** command allows you to set the starting values for each of the points with a distinct query.

For example....

<code python>
#We have loaded an array of values from before the requested range, 
#  in an array of 'Point Name' => 'Value' pairs...
for d in dta:
   history.SetInitialValue(d,dta[d])
</code>