Technical Tips

Real Time eXecutives, Inc.

Technical Tips

Adjusting the Historical Database Time Stamp

There are times when it is advantageous to adjust the apparent time stamp of the data in the RTXHDB database.  For example, daily average values are posted at the end of the day; the value posted at 4/1/2002 00:00:00 is the average of the values collected for the previous day (3/31/2002 from 00:00:00 to 23:59:59).  When viewed with a trending program, such as Trend Link – and especially when the graph type is ‘stair-step’ – it appears that the value reported at 4/1/2002 applies to the whole day 4/1/2002.  In fact, as stated, it applies to the day of 3/31/2002.

 Recognizing this issue, RTX has provided a means of artificially changing the data’s time stamp by means of a ‘time adjustment interval’.  Using our previous example, above, for a daily average database adjusting the apparent time stamp back one day makes the 4/1/2002 data have the time stamp of 3/31/2002 00:00:00.  Thus, when it is shown on a trend chart in a ‘stair-step’ mode, the step change will appear at the beginning of the period and hold through to the end of the period, reflecting the average value over that period.

The Time Adjustment Interval

The Time Adjustment Interval applies to a database.  That is, all data reporting for that database will be adjusted by the specified interval.  This will affect all variable reporting for that database, the time span reporting for that database, and the subset time span reporting for that database.  It will affect all RTXHDB client applications, including Trend Link, Excel Add-in, ODBC data retrieval, reports, etc.  It will not affect the data in the database in any way, nor does it affect propagations to and from that database.  The time adjustment interval can be changed at any time and will have an immediate affect on all variables viewed from that database.

Setting the Time Adjust Interval

Use the HDBMAINT program to set the Time Adjustment Interval.  From the HDBMAINT main dialog box, select ‘Databases’.  From the Databases dialog box, select the database to be changed and click the ‘Modify’ button to see the Database Definition dialog box.  From that dialog box, select the ‘Advanced’ tab and type in the adjustment interval.  For a six-minute database, for example, enter ‘-6’ and select the ‘Minutes’ time units.  Then close the dialog box.  Now, when Trend Link is initiated, it will recognize the time adjustment accordingly. 

 Last updated 04/08/2002 15:55:00

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