DBIx::Repgen - simple report generator from DB-selected data

NAME
SYNOPSIS
DESCRIPTION

new, class constructor

Current report data ��

run, report execution ��
Output
Get, querying of report parameters ��
Set, setting report parameters ��
Abort
Aborted

EXAMPLE

NAME

  DBIx::Repgen - simple report generator from DB-selected data

SYNOPSIS

 use Repgen;

 $r = DBIx::Repgen->new(
                 dbh => DBI->connect(...),
                 query => 'select ... from ...',

                 repdata => {
                             today => `date`
                            },

                 group => ['id'],
                 header => "========\n",
                 footer => sub {my ($r, $data) = @_; return "$data->{NAME} : $data->{VALUE}"},
                 item => ["%20s %s", qw/NAME VALUE/],

                 output => \$out;
                                 );

 $r->run(cust => 'tolik');
 print $out;

DESCRIPTION

�� DBIx::Repgen, �� , �� select-��. �� , �� , �� . �� : �� sprintf, �� .

This package implements class DBIx::Repgen, which is simple report generator from data received from relational database by some select-statement. Such a report can contain hyerarchical grouping by field values, record counters and cumulative totals (sums) of numeric fields for each group as well as for whole report. Each rerort part formatting may be set as literal string, arguments of sprint function or be code reference.

new, class constructor

�� , ��, �� .

Constructor has one argument, hashe. Elements of this hashe define the report and are descriebed below.

sth, dbh, query - data source setting

�� select-�� . �� .

The report data are got by executing some select statement against relational database environment. There are following wais for defining this statement.

�� sth �� (�.�. �� $dbh-prepare>), �� ($sth-execute>) �� .

Constructor receives in sth element prepared ($dbh-prepare>) but not executed ($sth-execute>) statement handle.
�� select-�� dbh � query, ��. �� prepare � execute �� .

Constructor receives database connection handle (from DBI-connect(...)>) and full text of select statement to be executed. Needed prepare and execute calls will perform by the report run.
�� (execute) ��, �� sql-�� . � �� ��  �� prepare � execute. �� , �� (�� Set) �� , �� .

� �� noexec �� true.

Constructor receives already prepared and executed statement handle. In this case noexec constructor parameter must be set to true. This feature may be useful by dynamic-made select queryes in calling programm. No prepare nor execute action will be performed by report run.

Important note: you have to reset (by Set method) this statemeny handle before each next report run.

 Samples:

 $dbh = DBI->connect('dbi:Oracle:SID', 'user', 'password');
 $sth1 = $dbh->prepare('select name, value from tab where value between ? and ?');
 $rep1 = DBIx::Repgen->new(sth => $sth);

 $rep2 = DBIx::Repgen->new(dbh => $dbh, query => "select ... ");

 $sth3 = $dbh->prepare('select ...');
 $sth3->execute(@param);
 $rep3 = DBIx::Repgen->new(sth => $sth3, noexec => 1);

�� , �.�. sql-�� placeholder-�, �� run. ��. �� .

Using first two methods you may parametrize the report. This means sql-query can contain placeholders, for substituting values in report run time. See below about report parameters.

param - report parameters

�� . �� , �� (�� ) placeholder-��, �� . �� , �� param. �� - �� , � �� placeholder-�� .

The report may have set of named parameters. Single parameter definition contain its name, number (or some numbers) of placeholders in source select query and optional default value. Parametrs definition is a hash reference, value of constructor's param element. Keys in this hash are parameter names and values contain placeholder numbers and default values.

� �� (zero based) �� placeholder-�, �� . � �� . �� �� �� n �� �� �� dflt, �� , �� , � �� - �� (��. �� ).

In the simpliest case parameter definition can be just zero-based number of the only placeholder corresponding to this parameter. In more complex cases is is hash reference. This hash must have n key with value of integer or list of integers and may have dflt key, which value must be scalar, code reference or array reference (where first element is code reference).

�� n �� (zero based) �� placeholder-�� select-��, �� , � dflt - �� . �� dflt �� , �� ��  �� . �� dflt �� , �� , �� , � �� - �� .

The n key defines zero based number (or numbers) of placeholdes in source select query corresponding to this parameter. The dflt key defines default value for optional parameters. If value of dflt is code reference then default value is result of this code call (without arguments). If value of dflt is array reference then first element of this array must be code reference. Default value of parameter in this case is result of call this code with arguments - the rest of array.

�� .

Sample of parameter definition.

  $rep = DBIx::Repgen->new(
    ...
    param => {
      name => 0,
      dep => {n => 1},
      startdate => {n => [2, 4], dflt => '2000/01/01'},
      enddate => {n => 3, dflt => \&DefEndDate},
      salary => {n => 5, dflt => [sub {...}, 1000, 2000]}
    }
  );

� �� name � dep - �� , �� placeholder-��. startdate �� , � �� placeholder-�. enddate � salary �� , �� , �� , ��.

In the example name and dep are required parameters corresponding to zero and first placeholders. startdate has explicit default value and substituted to second and fouth placeholders. enddate and salary have defaults defining by code call in report run time, without and with arguments in correspondence.

output - the way of report output �� 

�� output �� . �� .

The output constructor's parameter sets how and where the report puts its output data.

undef or not present: � �� run.; The whole output data are the result of run method call.
string reference: �� .; The output data are put into this string.
code reference: �� , �� - �� .; This code will be called with two arguments: the report object and string to be out.

Output samples.

 $r = DBIx::Repgen(...);
 print $r->run();

 $s = '';
 $r = DBIx::Repgen(..., output => \$s,);
 $r->run();
 print $s;

 sub myprint {
   my ($r, $s) = @_;
   print "*** $s ***";
 }
 $r = DBIx::Repgen(..., output => \&myprint,);
 $r->run();

group - repport groupping

�� ��. �� - �� , �� , � �� -�� (�� ) �� . � �� . �� group �� .

The report may be groupped. The group is sequence of records having the constant value of some field. This field called group field. The report may have several includded groups. For group setting you have to define group parameter of report constructor as a reference to an array of group fields.

�� , �� select-�� order by. �� .

Note that the right record's sequence must be provided by order part in used select query, not by report itself. Sample of grouping by countries and cities.

 $r = DBIx::Repgen->new(
   ...,
   query => "select country, city, population from cities
             order by country, city",
   group => [qw/COUNTRY CITY/],
   ...
 );

�� , �� �� �� , �� .

Note all field names are in uppercase, regardless used database server.

total - cumulative totals �� 

�� - �� , �� , �� . �� , �� . � �� . ��.

Value of this constructor's argument is reference to array with report fields to compute totals. Each field summation executed for all the report as well as for each group. See below about access to totals values.

header, footer, item etc. - definition of report parts � ��. - �� 

�� "��" (parts).

There are following parts during report output.

item: �� .; Outputs for each report's record.
header: �� .; Begin of whole report.
footer: �� .; Outputs after all, in the end of report.
header_GROUPFIELD: �� GROUPFIELD.; Outputs in the begin of record group by GROUPFIELD field.
footer_GROUPFIELD: �� GROUPFIELD.; Outputs after record group by GROUPFIELD field.

�� (�.�. �� ) �� .

Each of these report pats may be defined by several ways.

string ��

�� "�� ", �� .

The string will be printed "as is", without any procession.

 $r = DBIx::Repgen->new(
   header => "\t\tReport about countries and cities\n",
   ...
 );

reference to array of strings �� 

�� sprintf, � �� - �� �� (� �� !) � �� . �� . ��.

First element of this array have to be in form of sprintf function format. The rest of values in the array are names (no values!) of current report data. See below about current report data.

 $r = DBIx::Repgen->new(
   footer => ["Total %d countries, %d cities, population %d people\n",
              qw/num_COUNTRY num_CITY sum_POPULATION/],
   ...
 );

code reference �� 

�� - �� - �� .

The code is called with two arguments: report object and hash reference storing current report data. Subroutine may use Output method for output any needed information or just return output string as its result.

 $r = DBIx::Repgen->new(
   item => sub {
     my ($r, $d) = @_;
     $r->Output("%d %s",
                $d->{POPULATION},
                $d->{POPULATION} > 1_000_000 ? '*' : ' ');
   }

   footer => sub {return "Report ended at " . `date`}
   ...
    );

reference to array where first element is code reference �� , � �� - ��

�� : �� , �� , �� .

The code is called with following arguments: report object, current report data, the rest of array elements.

 $r = DBIx::Repgen->new(
   header_COUNTRY => [\&hfcountry, 'header'],
   header_COUNTRY => [\&hfcountry, 'footer'],
   ...
 );

 sub hfcountry {
  my ($r, $d, $header_or_footer) = @_;
  if ($header_or_footer eq 'header') {...} else {...};
 }

max_items - max record number limit �� 

�� (�� ), �� max_items ��. �� , �� Aborted (��. ��).

If this parameter (integer number) is present then no more than max_items records will be output. It is possible to know if not all records were output via Aborted method call.

Current report data ��

�� , �� . �� . �� .

All report state data are stored in internal report variables. Access to these data from report parts is possible by data names. There are following fields in current report data.

FIELDNAME: �� , �� select � �� .; Fields of current report's record. Name is in uppercase.
prev_FIELDNAME: �� . �� - �� , �� , �� , �.�. �� , �� .; Value of FIELDNAME in previous record. When group boundary is detected group field has new value, but its previous value is still stored. This value can be used in group footers.
num_report: �� . �� .; Number (one-based) of current output record for the whole report. This counter never resets.
num_item: �� .; Number of record in the innermost group.
num_GROUPNAME: �� .; Number of group GROUPNAME in including group.
total_FIELDNAME: �� . ��, �� FIELDNAME �� total ��.; Cumulative total of FIELDNAME field for the whole report. Remember FIELDNAME must be listed in total constructor's parameter.
total_GROUPNAME_FIELDNAME: �� .; Cumulative total by FIELDNAME field into GROUPNAME. These summators are reset each time the group boundary is reached.

run, report execution ��

 $r->run(%param);

�� . �� placeholder-�� execute �� (��. �� ). �� output, �� .

The report is run and output. Input parameters are substituted as values for select query placeholders (see above) about report's parameters. If there was no output constructor's parameter then the text of report returned as a result of this method.

Output

 $r->Output("Any values: %s and %d", 'qazwsx', 654);

�� - �� , �� sprintf. �� (�� output). �� , �� .

This method has the same arguments as sprintf function. It adds formatted string to the output stream (set by output param). This method is useful in the code called during the output of report parts.

Get, querying of report parameters ��

  @group = @{$r->Get('group')};

�� , �� Set.

Method returns value of named parameter which is set in constructor or via Set method.

Set, setting report parameters ��

 $r->Set(
   header => "Very new header",
   item => ["%s %s", qw/NAME VALUE/]
 );

�� .

Method redefines report parameters.

Abort

 $r->Abort();

�� , �� .

Being called in the code it breaks report running.

Aborted

  if ($r->Aborted()) {...}

�� - �� Abort �� .

Method returns true if report excution was aborted by Abort method.

EXAMPLE

�� , �� . �� , �� :

Full example of report and its result. The data are taken from data table having following structure.

 create table population (
  country varchar2(30) not null,
  city varchar2(30) not null,
  population int not null
 );

�� (�� !).

Full text of the perl script and output data are following. These are just demo data!

 #!/usr/bin/perl -w

 use strict;
 use DBI;
 use DBIx::Repgen;

 my $dbh = DBI->connect('dbi:Oracle:SID',
                    'user', 'password') or die $@;
 my $sth = $dbh->prepare(<<EOM);
 select
  country,
  city,
  population
 from
  population
 order by
  country,
  city
 EOM

 my $r = DBIx::Repgen->new
  (
   sth => $sth,
   group => [qw/COUNTRY/],
   total => [qw/POPULATION/],

   header => [\&makeheader,
              '=', "Countries, cities and thier population"],
   footer => ["Total %d countries, %d cities, %d people\n",
              qw/num_COUNTRY num_report total_POPULATION/],

   header_COUNTRY => sub {
     my (undef, $d) = @_;
     return makeheader(undef, undef, '-', $d->{COUNTRY});
   },
   footer_COUNTRY => ["%d cities, %d people in %s\n\n",
          qw/num_item total_COUNTRY_POPULATION prev_COUNTRY/],

   item => ["\t\t%-20s %10d\n", qw/CITY POPULATION/],
     );

 print $r->run();

 sub makeheader {
  my (undef, undef, $c, $s) = @_;
  return sprintf("%s\n%s\n%s\n", $c x length($s), $s, $c x length($s));
 }

 ======================================
 Countries, cities and thier population
 ======================================
 ---------
 Australia
 ---------
                Kanberra                 900000
                Sidney                  6400000
 2 cities, 7300000 people in Australia

 ------
 Russia
 ------
                Moscow                  9500000
                Rostov-on-Don           1200000
                St.Petersberg           4500000
                Taganrog                 250000
 4 cities, 15450000 people in Russia

 ---
 USA
 ---
                Los Angeles             4000000
                New York               12000000
                Washington              2000000
 3 cities, 18000000 people in USA

 Total 3 countries, 9 cities, 40750000 people