Datalog Educational System Files

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  | DES INSTALLATION (quick guide) |
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Windows Binary Distribution with ACIDE GUI
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- Double-click on des_acide.jar for starting the 
  ACIDE GUI

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Windows Binary Distribution
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- Double-click on deswin.exe for starting the Windows
  application
- Execute des.exe for starting the console application

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Linux/MacOSX Binary Distribution with ACIDE GUI
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- Add execute permission to file des, typically with:
  chmod +x ./bin/des
  or from the file explorer.
- Start ACIDE from a terminal with:
  java -jar des_acide.jar  

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Linux/MacOSX Binary Distribution
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- Add execute persmission to file des, typically with:
  chmod +x ./des
  or from the file explorer.
- Start ./des in a terminal from its installation path

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Windows Source Distributions
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1. Create a shortcut in the desktop for running the Prolog 
   interpreter of your choice. 
2. Modify the start directory in the "Properties" dialog box 
   of the shortcut to the installation directory for DES. 
   This allows the system to consult the needed files at startup.
3. Append the following options to the Prolog executable complete 
   filename, depending on the Prolog interpreter you use:
   (a) SICStus Prolog: -l des.pl
   (b) SWI Prolog: -g "ensure_loaded(des)" (remove --win_app if 
     present)
Another alternative is to write a batch file similar to the 
script file described just in the above section.
    
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Linux/MacOSX Source Distributions
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You can write a script for starting DES according to the 
selected Prolog interpreter, as follows:
(a) SICStus Prolog: 
    $SICSTUS -l des.pl 
    Provided that $SICSTUS is the variable which holds 
    the absolute filename of the SICStus Prolog executable.
(b) SWI Prolog: 
    $SWI -g "ensure_loaded(des)"
    Provided that $SWI is the variable which holds the 
    absolute filename of the SWI Prolog executable.

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More Information: 
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- See User Manual
  'Documentation' entry in 
  http://des.sourceforge.net/html/download.html
- http://des.sourceforge.net


Version 4.2 of DES (released on September, 25th, 2016)
 
* Enhancements:
  o Date and time-related data types date, time and datetime (also 
    timestamp following standard SQL) for relations (Datalog and SQL)
  o Evaluable expressions (in both Datalog and SQL) also support 
    string and date/time/datetime types (evaluable expressions were only
    arithmetic up to previous version)
  o Built-in Datalog predicates for string handling ($concat/3, 
    $length/2, $like/2, $like/3, $lower/2, $substr/4, $upper/2)
  o Built-in Datalog predicates for date/time/datetime handling 
    ($year/2, $month/2, $day/2, $current_date/1, $current_time/1, 
    $current_timestamp/1)
  o Functions and operators for string handling (concat, length, 
    like-escape, lower, substr, upper, ||, +)
  o Functions for date/time/datetime handling (year, month, day, hour,
    minute, second, current_time, current_date, current_datetime). 
  o The SQL standard function extract is also available (for SQL, RA, 
    TRC and DRC), which extracts the value of the given field from a 
    date/time/timestamp value
  o Overloading for the operators +, - which can be applied to number,
    string, and date/time/timestamp types
  o Comparison operators also range on date and time values
  o Time and date value inputs are normalized
  o Datalog and SQL date, time and timestamp constants as, e.g.:
    - date(2016,08,31) and DATE '2016-08-31', both representing August
      31st 2016 for Datalog and SQL respectively
    - time(18,30,44) and TIME '18:30:44', in 24 hour format for the 
      same time for Datalog and SQL respectively
    - datetime(2016,08,31,18,30,44) , DATETIME '2016-08-31 18:30:44', 
      TIMESTAMP '2016-08-31 18:30:44', all three representing the same 
      timestamp (first one for Datalog and the others for SQL)
  o Function (cast) and predicate ('$cast'/3) for type casting between
    appropriate types
  o Added an ACIDE lexicon for DRC and TRC
  o New SQL DDL statement CREATE TABLE Name AS Statement
  o Added trunc as a synonym for truncate

  
* Fixed bugs:
  o Some exceptions did not clear the asserted answer rules
  o Evaluating a compound arithmetic expression of a variable bound to
    a null failed for aggregates providing this value