NAME

Bigtop::Backend::Diagram::GraphvizSql - generates dot language file for data model

SYNOPSIS

If your bigtop file looks like this:

    config {
        SQL      ...      {}
        Diagram  Graphviz {}
    }
    app App::Name {
    }

and there are table blocks in the app block, this module will make docs/schema.graphviz (relative to the build_dir) when you type:

    bigtop app.bigtop Diagram

or

    bigtop app.bigtop all

This generates docs/schema.graphviz. By default this backend also runs the following command:

    dot -Tpdf docs/schema.graphviz > docs/schema.pdf

Use backend_block_keywords described below to control the behavior.

DESCRIPTION

This is a Bigtop backend which generates a file in the dot language understood by all the Graphviz tools. For information about Graphviz, please visit http://www.graphviz.org. To summarize, the files generated by this module can be fed through dot or neato to produce a .png file (many other formats are available) showing the data model for your project.

KEYWORDS

This module assumes you are using one of the SQL backends which will define appropriate keywords for table and field definitions. But, it defines three words of its own:

label

This is valid keyword for both the app and table levels. The app label becomes the label for the whole picture. The table label becomes the label for the record box of the table. If these label keywords are not used the app name and table name are used instead, but split on underscores and ucfirst applied to all the words which are rejoined with a single space.

quasi_refers_to

This is valid at the field level and indicates that the field's value refers to a field in another table whenever the value is not null. In the picture these links are drawn with dotted lines.

METHODS

To keep podcoverage tests happy.

backend_block_keywords

Tells tentmaker that I understand these config section backend block keywords:

    no_gen
    template
    skip_layout
    layout_program
    layout_flags

As mentioned in the SYNOPSIS above, by default this backend runs the following command:

    dot -Tpdf docs/schema.graphviz > docs/schema.pdf

If skip_layout is present and true, no such command is run. All you get is docs/schema.graphviz. This flag supercedes the other keywords.

layout_program defaults to dot, but this keyword lets you change to any other interpretter of the dot language. One of these is neato. There are others. In my humble opinion, only dot looks good for this type of diagram, so I stick with it.

layout_flags lets you pass things to your layout program. Feel free to pass anything. If you use -T, the generated file will have the -T value as its file extension. So this:

    layout_flags `-Tpng`

will actually execute this:

    dot -Tpng docs/schema.graphviz > docs/schema.png

If you omit -T a -Tpdf will be added for you. No other flags are parsed.

what_do_you_make

Tells tentmaker what this module makes. Summary: docs/schema.graphviz.

gen_Diagram

Called by Bigtop::Parser to get me to do my thing.

setup_template

Called by Bigtop::Parser so the user can substitute an alternate template for the hard coded one here.

AUTHOR

Phil Crow <crow.phil@gmail.com>

COPYRIGHT and LICENSE

Copyright (C) 2010 by Phil Crow

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.10.0 or, at your option, any later version of Perl 5 you may have available.