Below are frequently asked questions for DateWise FileCompare.  For other questions, visit our Postings page or email

DateWise FileCompare Frequently Asked Questions:

Q1: How can FileCompare know where the dates are, if one does not tell the tool where they are?

A1: The DateWise FileCompare tool does not know where the dates are without additional input. That additional input is the two files being compared.   It utilizes artificial intelligence techniques to search for dates.  In fact, if it is provided two files one of which is an aged version of the other and ask it what the difference between the two files it will typically provide answers such as they differ by either 365 days or 1 year.  (The tool can actually calculate the difference between aged files, even if one of the files has some dates reformatted.)

Q2: How many date formats will the DateWise FileCompare tool recognize?

A2: This tool uses a parsing technique for recognizing dates. It will recognize literally thousands of date formats. This includes those with characters, numbers, separators and/or optional elements in binary, encoding or plain text.

Q3: I use a proprietary format for my dates of the number of days since January 1, 1850, can the DateWise FileCompare tool work for me?

A3: Yes, it will. Unless you converted to a different format, the base date does not matter since the tool is only interested in the quantity of time between two dates (which is the same for any base date).  If you did convert to another format, there is an option to enter the conversion factor.

Q4: What optional features have not been added to DateWise FileCompare?

A4: Semantic aging and time stamp handling will be added at specific customer requests.  The reason for this is that there are many switches which could be implemented for these, most of which would never be used by anyone.  Furthermore, implimenting semantic aging for the comparison tool would miss leap year problems in the data.  We have decided that we will implement those which are actually needed upon request.

Q5: I have packed four digits of the year in the same space as the original two digit year, will the DateWise FileCompare tool work for me?

A5: Yes, but it will require some fine tuning by the manufacturer from the standard version. Contact us with the specifics of your methodology.

Q6: What if there are two possible interpretations of a date from each file that match. How can the DateWise FileCompare tool accurately identify which one is correct?

A6: When the dates really do match, this situation actually happens frequently.  For example, if a date with a 2-digit year matches and 1-digit years are enable, there will almost always be multiple matches for dates in the ten year range of the 1-digit year.  The algorithm handles the problem in the most sure way. There is a slim chance of a single pair of mismatched dates being declared as matches by the program.

There is a corresponding possibility of bad data passing as good in any testing, just based on the data passed to the program. For example, consider a function to calculate squares of any value. If the program is mis-typed slightly, using a single "*" (for multiplication) rather than the proper symbol "**" (for exponentiation) and tested with the data values "0" and "2", it would pass testing. This is no different with the DateWise FileCompare tool. Certain combinations of data will pass testing, others will not.

Utilizing the switches we provide with the tool, we are usually able to make the comparison almost as tight as a comparison done by manually identifying record types, location and format of dates.  It is surprisingly powerful to specify that all the dates in the regression file contain dates with 2-digit years that fall between 1900 and 1999, dates with 1-digit years that fall between 1989 and 1998, and there are no dates with 3-digit or 0-digit years without specifying anything about the second file, for example.  Alternatively, specifying that the numeric dates in the second file are standardized on 7-digit Julian dates, or dates of the format CCYYMMDD and not specify anything about the first file.  For a very tight tight compare, one could specify information on both files.

For this reason, in any testing effort, some diversity of data or test scenarios is expected when using this tool.

Q7: How does the process work?

A7: Well, internal details are proprietary but a demo is available freely by completing an industry standard non-disclosure agreement, so you can freely verify for yourself it does work using your own data.  For a copy of the demo, email your request to

Q8: What are the limitations of the process?

A8: The following is a list of all known limitations:

Time stamps not currently handled The tool currently has limited facility for handling time stamps.  That will be added as formats for time stamps are identified
Native formats (Such as BDAM, ISAM, etc) Not currently supported except by copying the file to a sequential format.   This is a limitation of wanting to maintain a single source file initially.
Expects multiple records of each type to help catch errors Reduces the chance that some random value will pass the comparison test.
Expects the dates to be aged by a constant number of days or skipped in aging All dates in reference file are expected to differ by a constant number of days from the base file.