Operational historian

[1] Historian software is often embedded or used in conjunction with standard DCS and PLC control systems to provide enhanced data capture, validation, compression, and aggregation capabilities.

Front-end tools for trending process data over time are the most common interfaces to these databases.

Because these applications are typically deployed next to or near the source of their process data, these are often marketed and sold as 'real-time database systems.'

This distinction varies among vendors who often have to make development choices between performance in capturing and presenting data vs. application and analysis functionality.

In most of such implementations, the dialect does not follow the SQL standard in order to provide syntax for specifying data access operations parameters.