1GraphViz2::DBI(3)     User Contributed Perl Documentation    GraphViz2::DBI(3)
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NAME

6       GraphViz2::DBI - Visualize a database schema as a graph
7

Synopsis

9               #!/usr/bin/env perl
10
11               use strict;
12               use warnings;
13
14               use DBI;
15
16               use GraphViz2;
17               use GraphViz2::DBI;
18
19               use Log::Handler;
20
21               # ---------------
22
23               exit 0 if (! $ENV{DBI_DSN});
24
25               my($logger) = Log::Handler -> new;
26
27               $logger -> add
28                       (
29                        screen =>
30                        {
31                                maxlevel       => 'debug',
32                                message_layout => '%m',
33                                minlevel       => 'error',
34                        }
35                       );
36
37               my($graph) = GraphViz2 -> new
38                       (
39                        edge   => {color => 'grey'},
40                        global => {directed => 1},
41                        graph  => {rankdir => 'TB'},
42                        logger => $logger,
43                        node   => {color => 'blue', shape => 'oval'},
44                       );
45               my($attr)              = {};
46               $$attr{sqlite_unicode} = 1 if ($ENV{DBI_DSN} =~ /SQLite/i);
47               my($dbh)               = DBI -> connect($ENV{DBI_DSN}, $ENV{DBI_USER}, $ENV{DBI_PASS}, $attr);
48
49               $dbh -> do('PRAGMA foreign_keys = ON') if ($ENV{DBI_DSN} =~ /SQLite/i);
50
51               my($g) = GraphViz2::DBI -> new(dbh => $dbh, graph => $graph);
52
53               $g -> create(name => '');
54
55               my($format)      = shift || 'svg';
56               my($output_file) = shift || File::Spec -> catfile('html', "dbi.schema.$format");
57
58               $graph -> run(format => $format, output_file => $output_file);
59
60       See scripts/dbi.schema.pl ("Scripts Shipped with this Module" in
61       GraphViz2).
62
63       The image html/dbi.schema.svg was generated from the database tables of
64       my module App::Office::Contacts.
65

Description

67       Takes a database handle, and graphs the schema.
68
69       You can write the result in any format supported by Graphviz
70       <http://www.graphviz.org/>.
71
72       Here is the list of output formats
73       <http://www.graphviz.org/content/output-formats>.
74

Distributions

76       This module is available as a Unix-style distro (*.tgz).
77
78       See <http://savage.net.au/Perl-modules/html/installing-a-module.html>
79       for help on unpacking and installing distros.
80

Installation

82       Install GraphViz2 as you would for any "Perl" module:
83
84       Run:
85
86               cpanm GraphViz2
87
88       or run:
89
90               sudo cpan GraphViz2
91
92       or unpack the distro, and then either:
93
94               perl Build.PL
95               ./Build
96               ./Build test
97               sudo ./Build install
98
99       or:
100
101               perl Makefile.PL
102               make (or dmake or nmake)
103               make test
104               make install
105

Constructor and Initialization

107   Calling new()
108       "new()" is called as "my($obj) = GraphViz2::DBI -> new(k1 => v1, k2 =>
109       v2, ...)".
110
111       It returns a new object of type "GraphViz2::DBI".
112
113       Key-value pairs accepted in the parameter list:
114
115       o dbh => $dbh
116           This options specifies the database handle to use.
117
118           This key is mandatory.
119
120       o graph => $graphviz_object
121           This option specifies the GraphViz2 object to use. This allows you
122           to configure it as desired.
123
124           The default is GraphViz2 -> new. The default attributes are the
125           same as in the synopsis, above, except for the graph label of
126           course.
127
128           This key is optional.
129

Methods

131   create(exclude => [], include => [], name => $name)
132       Creates the graph, which is accessible via the graph() method, or via
133       the graph object you passed to new().
134
135       Returns $self to allow method chaining.
136
137       Parameters:
138
139       o exclude
140           An optional arrayref of table names to exclude.
141
142           If none are listed for exclusion, all tables are included.
143
144       o include
145           An optional arrayref of table names to include.
146
147           If none are listed for inclusion, all tables are included.
148
149       o name
150           $name is the string which will be placed in the root node of the
151           tree.  It may be omitted, in which case the root node is omitted.
152
153   graph()
154       Returns the graph object, either the one supplied to new() or the one
155       created during the call to new().
156

FAQ

158   Why did I get an error about 'Unable to find primary key'?
159       For plotting foreign keys, the code has an algorithm to find the
160       primary table/key pair which the foreign table/key pair point to.
161
162       The steps are listed here, in the order they are tested. The first
163       match stops the search.
164
165       o Check a hash for special cases
166           Currently, the only special case is a foreign key of "spouse_id".
167           It is assumed to point to a primary key called "person_id".
168
169           There is no option available, at the moment, to override this
170           check.
171
172       o Ask the database for foreign key information
173           DBIx::Admin::TableInfo is used for this.
174
175       o Take a guess
176           Assume the foreign key points to a table with a column called "id",
177           and use that as the primary key.
178
179       o Die with a detailed error message
180
181   Which versions of the servers did you test?
182       See "FAQ" in DBIx::Admin::TableInfo.
183
184   Does GraphViz2::DBI work with SQLite databases?
185       Yes. See "FAQ" in DBIx::Admin::TableInfo.
186
187   What is returned by SQLite's "pragma foreign_key_list($table_name)"?
188       See "FAQ" in DBIx::Admin::TableInfo.
189
190   How does GraphViz2::DBI draw edges from foreign keys to primary keys?
191       It assumes that the primary table's name is a plural word, and that the
192       foreign key's name is prefixed by the singular of the primary table's
193       name, separated by '_'.
194
195       Thus a (primary) table 'people' with a primary key 'id' will be pointed
196       to by a table 'phone_numbers' using a column 'person_id'.
197
198       Table 'phone_numbers' will probably have a primary key 'id' but that is
199       not used (unless some other table has a foreign key pointing to the
200       'phone_numbers' table).
201
202       The conversion of plural to singular is done with
203       Lingua::EN::PluralToSingular.
204
205       If this naming convention does not hold, then both the source and
206       destination ports default to '1', which is the port of the 1st column
207       (in alphabetical order) in each table. The table name itself is port
208       '0'.
209
210   Are any sample scripts shipped with this module?
211       Yes. See "FAQ" in GraphViz2 and "Scripts Shipped with this Module" in
212       GraphViz2.
213

Thanks

215       Many thanks to the people who chose to make Graphviz
216       <http://www.graphviz.org/> Open Source.
217
218       And thanks to Leon Brocard <http://search.cpan.org/~lbrocard/>, who
219       wrote GraphViz, and kindly gave me co-maint of the module.
220

Version Numbers

222       Version numbers < 1.00 represent development versions. From 1.00 up,
223       they are production versions.
224

Machine-Readable Change Log

226       The file Changes was converted into Changelog.ini by
227       Module::Metadata::Changes.
228

Support

230       Email the author, or log a bug on RT:
231
232       <https://rt.cpan.org/Public/Dist/Display.html?Name=GraphViz2>.
233

Author

235       GraphViz2 was written by Ron Savage <ron@savage.net.au> in 2011.
236
237       Home page: <http://savage.net.au/index.html>.
238

240       Australian copyright (c) 2011, Ron Savage.
241
242               All Programs of mine are 'OSI Certified Open Source Software';
243               you can redistribute them and/or modify them under the terms of
244               The Perl License, a copy of which is available at:
245               http://dev.perl.org/licenses/
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249perl v5.32.0                      2020-07-28                 GraphViz2::DBI(3)
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