Using PI-ODBC Server users can store process information in the PI-Data Archive that is ideal for storing time-oriented data and then use standard ODBC calls to access values. Relational databases contain tables that are generally used for applications not directly related to continuous data collection, such as raw material control, production scheduling, and monitoring product quality versus customer specifications. Typically these applications include summary data of the process because a relational database is not designed to accommodate the raw data. With PI-ODBC, the data resides in the PI-Data Archive and the desired summary data are actually a "virtual table" created on demand when a call is executed. PI-ODBC supports the following summary "tables" , which can be applied to most variables for any time period:
Standard deviation (pistd)
Time weighted average (piavg)
Arithmetic average (pimean)
The PI-SQL subsystem prepares and executes SQL statements directed at the PI Server. The primary user of this subsystem is the PI-ODBC Driver.
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