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. Requires Java JDK 1.8

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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 files des and des_start,
  typically with:
    chmod +x ./bin/des
    chmod +x ./bin/des_start
  or from the file explorer.
- Check unixodbc is installed
- Start ACIDE from a terminal with:
  java -jar des_acide.jar  
  Requires Java JDK 1.8

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Linux/MacOSX Binary Distribution
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- Add execute permission to files des and des_start,
  typically with:
    chmod +x ./bin/des
    chmod +x ./bin/des_start
  or from the file explorer.
- Check unixodbc is installed
- 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.io/html/download.html
- http://des.sourceforge.io


Version Devel of DES (released on March, 10th, 2026)
 
* Enhancements:
  o SQL semantic checking of inconsistent and tautological conditions 
    is extended to dependent views
  o Foreign keys can omit the referenced column names, assuming the 
    primary key columns of the referenced table to be the external key
  o Extended SQL CASE for dealing with expressions as arguments
  o Compile-time type checking for arguments of SQL built-ins 
    COALESCE, GREATEST, LEAST, NVL, NVL2, IIF and CASE
  o Supported OFFSET and LIMIT clauses in SQL hints
  o Absorption rules added for conjunction and disjunction, enabling 
    more optimization opportunities
  o Added BIGINT SQL type
  o New commands:
    - /cls Clear the console screen by issuing ANSI escape sequences, 
      which must be supported and enabled by the console 
    - /sql_semantic_check_data Display whether SQL semantic check 
      based on actual data is enabled (disabled by default). If enabled,
      data from tables are used for consistency checks and query 
      simplifications
    - /sql_semantic_check_data Switch Enable or disable actual data 
      for SQL semantic check (on or off, resp.) If enabled, data from 
      tables are used for consistency checks and query simplifications

* Changes:
  o SQL queries that include FROM dual or are FROM-less are now 
    displayed without a FROM clause on DBMS's that support it; in 
    particular, for DES
  o SQL queries that include a top-N clause are now displayed with its
    simplified version SELECT TOP N on DBMS's that support it; in 
    particular, for DES
  
* Fixed bugs:
  o Some translations of projections to canonical RA in the 
    compilation of SQL queries were omitted. This might lead to 
    compilation errors
  o The operator != was not accepted in DRC
  o Type conversion failed in some corner cases involving disjunctions
    ('$eq' was not treated as an infix comparison)