DES 6.5 Released

[Apologies for multiple receptions]

Hoping and wishing the best in current circumstances, this
is a mail just for informing that the new release

Datalog Educational System version 6.5

has been launched on April, 10th, 2020, and tested for

SICStus Prolog 4.4.1
SWI-Prolog 7.4.2

The current version mainly improves SQL features. First,
automatic type casting has been enhanced for dealing with
values of different data types, both at compile-time and at
run-time. Casting includes matching values of different
types for which compatible values exist (for example, a
string containing a valid date and a date value). Second,
compilations have been improved (more deterministic type
inference, semantic analysis precision for some built-ins,
smaller intermediate relations, …). Third, better error
messages for aggregates are issued. Fourth, support for SQL
has been extended (including both standard and non-standard
features). Finally, other commands have been added, changes
have been made and some bugs have been fixed.

A complete list of enhancements and fixed bugs is attached
to the end of this message.
Please, see for details.

Best regards.

Fernando Saenz Perez
Profesor Titular de Universidad / Associate Professor
Home Page:
Tel: + 34 913947576. Fax: + 34 913947547
Despacho / Office: 435 (4a. planta / 4th floor)
Dept. Ingenieria del Software e Inteligencia Artificial /
Department of Software Engineering and Artificial
Universidad Complutense de Madrid
Facultad de Informatica
C/Profesor Jose Garcia Santesmases, s/n
E - 28040 Madrid. Spain


Version 6.5 of DES (released on April, 10th, 2020)

  • Enhancements:
    o Improved automatic type casting for dealing with values
    of different data types, both at compile-time and at
    o More deterministic type inference, improving analysis
    o Improved SQL semantic analysis precision for some
    built-in predicates
    o Better compilations for some aggregate metapredicates,
    reducing the number of arguments
    o Better SQL compilations by simplifying evaluable goals
    o Better compilations for relations in group_by predicate
    (intermediate predicates with less arguments)
    o Some bad uses of aggregates are issued at compile-time
    (as errors), instead of at run-time (as an exception)
    o SQL grouping error messages extended with column names
    o Left operand of SQL LIKE operator can be a tuple of
    expressions (instead of just constants or columns)
    o SQL strings can include escaped apostrophes with the
    backslash, in addition to the already supported double
    o The SQL ALTER TABLE statement has been extended to deal
    with table columns: redefining a column (both its data
    type and constraints) or only changing its data type
    o ORDER BY expressions can contain aggregates and include
    positional notation
    o Added SQL logical operator XOR
    o Added round function with two arguments, and its
    corresponding predicate
    o Time and datetime formatting (in addition to the already
    supported date formatting). Enabled by default and set
    with the command /format_datetime
    o The command /date_format admits date formats delimited
    by single quotes
    o New commands:

    • /describe Relation Synonym for /db_schema Relation,
      where Relation can only be either a table or a view,
      possibly qualified with the database name (as
    • /tapi_log Display whether TAPI logging is enabled. If
      enabled, both TAPI commands and their results are not
    • /tapi_log Switch Enable or disable TAPI logging (on or
      off, resp.) If enabled, both TAPI commands and their
      results are not logged
  • Changes:
    o Changing the type casting mode recompiles views in the
    local database
    o TAPI inputs and their results are not logged by default
    o Most types from external databases are shown normalized,
    instead using their particular naming
    o Normalized name types for ODBC connections

  • Fixed bugs:
    o A case in simplifying goals was incorrect, dealing to
    incorrect translations and semantic deductions
    o The CASCADE modifier parsing was included in version 6.4
    but its processing was not implemented
    o Wrong partial reduction when unfolding some
    metapredicates for disjunctions
    o A non-valid date format specified by the command
    /date_format would lead to non-termination
    o Incorrect type error when comparing a string constant
    with a limited-size string type
    o Incorrect exception in SQL truncate function
    o ODBC varchar type sizes were not correctly retrieved
    o In SICStus distros, nulls were not grounded for external
    o Some SQL error messages about bad groupings were not
    o Logging information was duplicated in /status

// ACIDE 0.17 Release Notes //
// September, 10th 2015 //

  • Enhancements, changes and fixed bugs:
    o Localization to French
    o Multiple editors for new files
    o New Reset and Refresh buttons for the Database panel
    o The Datalog query for Trace Datalog becomes single-lined
    o Keyboard shortcut (F9) for Play
    o Rule (SQL statement, resp.) location becomes disabled
    by-default in Trace Datalog (Trace SQL, resp.)
    o New Debug SQL panel but with incomplete functionality
    o Bug fixes in several panels (Console, Database, …) but
    presumably others added.

o Ctrl+Mouse Wheel for resizing font display may take long
time depending on the number of open file editors.
o Opening medium-sized text files may take long time due
to lexical analysis. No progress indicators are provided.
Only when all editor windows are processed they are
o As an alpha version, there are expected many bugs and
incomplete functionalities. Please report them to