You can extract data in full and automatically by eliminating the -begindate, -begintime, -enddate, -endtime parameters in the command line or by using -valueconstraint with no value for the first comparison operator. If the data range to be extracted is restricted using integer values, either the smallest or largest of the last values extracted is saved or updated in the configuration file used. If there are time restrictions on the data range to be extracted, the time of the last data extraction is saved or updated in the configuration file.
The following conditions must be met:
runjdbc2ppm -datasource datasource.xml -valueconstraint ">"
Example 1 (lastreadvalue with default value "0")
-valueconstraint ">="
Only those data records are extracted whose integer value for restricting the data range to be extracted is greater than or equal to the value saved as the last value extracted (lastreadvalue) in the system configuration or data source. If no value is saved, the default value 0 is used (in the example, all data records with integer criterion values >=0 would be extracted). The greatest of the last values extracted (300 in this example) is saved as lastreadvalue according to the default setting (see -save_value_minimum parameter).
Example 2 (lastreadvalue="40")
-valueconstraint ">=" 270 "<="
All data records are extracted that have an integer value of >=40 and <=270 for restricting the data range to be extracted. After the extraction, the value for lastreadvalue is updated, e.g., to 270 if this is really the greatest of the last values extracted.
Example 3 (lastreaddate="19971231" lastreadtime="155959" lastreadvalue="270")
By calling up
runjdbc2ppm -datasource datasource.xml -valueconstraint ">"
again all data records are extracted whose integer value for delimiting the data range to be extracted is greater than 270 and whose time stamp is as old as or more recent than the start time of the data extraction (31.12.1997 15:59:59).
The start time of data extraction is entered as lastreaddate/lastreadtime in the configuration file.
If you eliminate the -begindate/-begintime parameters, you always extract the data records whose time stamps are more recent (greater) than the ones specified and last extracted using lastreaddate/lastreadtime. The current date and time are entered as lastreaddate/lastreadtime if you do not use the -enddate and -endtime parameters.