The first visualization tool in SQLFairy, this producer uses libgd to
draw a picture of the schema. The tables are evenly distributed in
definition order running in columns (i.e., no graphing algorithms are
-used), so the end result may result in many crossed lines showing the
-foreign key relationships. Please read the documentation of the
-"sqlt-diagram" script for all the options available to this producer.
+used), so the many of the lines showing the foreign key relationships
+may cross over each other and the table boxes. Please read the
+documentation of the "sqlt-diagram" script for all the options
+available to this producer.
=item * GraphViz
Now that you have seen how the parsers and producers interact via the
Schema objects, you may wish to create your own versions to plugin.
+Producers are probably the easier concept to grok, so let's cover that
+first. By far the easiest way to create custom output is to use the
+TTSchema producer in conjunction with a Template Toolkit template as
+described earlier. However, you can also easily pass a reference to a
+subroutine that SQL::Translator can call for the production of the
+ouput. This subroutine will be passed a single argument of the
+SQL::Translator object which you can use to access the Schema objects.
+Please read the POD for SQL::Translator and SQL::Translator::Schema to
+learn the methods you can call. Here is a very simple example:
+
+ #!/usr/bin/perl
+
+ use SQL::Translator;
+
+ my $input = q[
+ create table foo (
+ foo_id int not null default '0' primary key,
+ foo_name varchar(30) not null default ''
+ );
+
+ create table bar (
+ bar_id int not null default '0' primary key,
+ bar_value varchar(100) not null default ''
+ );
+ ];
+
+ my $t = SQL::Translator->new;
+ $t->parser('MySQL') or die $t->error;
+ $t->producer( \&produce ) or die $t->error;
+ my $output = $t->translate( \$input ) or die $t->error;
+ print $output;
+
+ sub produce {
+ my $tr = shift;
+ my $schema = $tr->schema;
+ my $output = '';
+ for my $t ( $schema->get_tables ) {
+ $output .= join('', "Table = ", $t->name, "\n");
+ }
+ return $output;
+ }
+
+Executing this script produces the following:
+
+ $ ./my-producer.pl
+ Table = foo
+ Table = bar
+
+A custom parser will be passed two arguments: the SQL::Translator
+object and the data to be parsed. In this example, the schema will be
+represented in a simple text format. Each line is a table definition
+where the fields are separated by colons. The first field is the
+table name and the following fields are column definitions where the
+column name, data type and size are separated by spaces. The
+specifics of the example are unimportant -- what is being demonstrated
+is that you have to decide how to parse the incoming data and then
+map the concepts in the data to the Schema object.
+
+ #!/usr/bin/perl
+
+ use strict;
+ use SQL::Translator;
+
+ my $input =
+ "foo:foo_id int 11:foo_name varchar 30\n" .
+ "bar:bar_id int 11:bar_value varchar 30"
+ ;
+
+ my $t = SQL::Translator->new;
+ $t->parser( \&parser ) or die $t->error;
+ $t->producer('Oracle') or die $t->error;
+ my $output = $t->translate( \$input ) or die $t->error;
+ print $output;
+
+ sub parser {
+ my ( $tr, $data ) = @_;
+ my $schema = $tr->schema;
+
+ for my $line ( split( /\n/, $data ) ) {
+ my ( $table_name, @fields ) = split( /:/, $line );
+ my $table = $schema->add_table( name => $table_name )
+ or die $schema->error;
+ for ( @fields ) {
+ my ( $f_name, $type, $size ) = split;
+ $table->add_field(
+ name => $f_name,
+ data_type => $type,
+ size => $size,
+ ) or die $table->error;
+ }
+ }
+
+ return 1;
+ }
+
+And here is the output produced by this script:
+
+ --
+ -- Created by SQL::Translator::Producer::Oracle
+ -- Created on Wed Mar 31 15:43:30 2004
+ --
+ --
+ -- Table: foo
+ --
+
+ CREATE TABLE foo (
+ foo_id number(11),
+ foo_name varchar2(30)
+ );
+
+ --
+ -- Table: bar
+ --
+
+ CREATE TABLE bar (
+ bar_id number(11),
+ bar_value varchar2(30)
+ );
+
=head1 AUTHOR
Ken Y. Clark E<lt>kclark@cpan.orgE<gt>.
projects / dbsrgits/SQL-Translator.git / commitdiff