IIUG Software Repository Files

Examples in Hierarchical Data Structures
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The accompanying shell scripts, ACE report and SQL files can be used to
demonstrate how to handle hierarchical data structures (eg Bill of
Materials or Organisation Chart) in SQL.

The Bill of Materials (BoM) solutions (partexp1..partexp4) illustrate
the use of Breadth-First-Search.  The Organisation Chart (OC) solution
(hier2) illustrates Depth-First-Search.  Note that neither solution is
neat and tidy, though the BoM is simply iterative whereas the OC
solution requires a recursively defined table structure.

The solutions use my program SQLCMD as an SQL command interpreter.  The
equivalent effect can more or less be achieved using either ISQL or
DBACCESS, but it is not as easy, and some cases would require the output
from ISQL/DBACCESS to be reformatted to retain the data one row per
line.  (Where the command is of the form sqlcmd -d dbase -e "SQL stmt",
use echo "SQL stmt" | isql dbase -; where the command is of the form
sqlcmd -d dbase -f file.sql, use isql dbase file; where the command is
of the form sqlcmd -d dbase file1.sql file2.sql, use cat file1.sql
file2.sql | isql dbase -; when -D is used, set DBDELIMITER to the
argument value.  When -F unload is used, change the last SELECT
statement into an unload statement.)  Contact me for source to SQLCMD.

The Makefile has the targets all, dbase and runit.  All makes the
requisite files, dbase creates and loads the database, and runit runs
the various programs.  A sample output is included called runit.log.

Note that both sets of data have random number sequences.  The OC code
was initially developed with a neat and tidy (non-random) sequence for
the identifiers, and a neat and tidy solution was the result.  When the
numbers were randomised, that solution fell to bits, so the current
hier2 solution was developed.  Beware when adapting the code of this
potential problem; simple sample data may easily mislead you.

Jonathan Leffer
Informix Software
@(#)README	1.1 93/03/03