Adding Jess's DB2 DBI parser.

[dbsrgits/SQL-Translator.git] / lib / SQL / Translator / Parser / PostgreSQL.pm

package SQL::Translator::Parser::PostgreSQL;

# -------------------------------------------------------------------
# $Id: PostgreSQL.pm,v 1.39 2004-08-11 22:00:39 kycl4rk Exp $
# -------------------------------------------------------------------
# Copyright (C) 2002-4 SQLFairy Authors
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
# 02111-1307  USA
# -------------------------------------------------------------------

=head1 NAME

SQL::Translator::Parser::PostgreSQL - parser for PostgreSQL

=head1 SYNOPSIS

  use SQL::Translator;
  use SQL::Translator::Parser::PostgreSQL;

  my $translator = SQL::Translator->new;
  $translator->parser("SQL::Translator::Parser::PostgreSQL");

=head1 DESCRIPTION

The grammar was started from the MySQL parsers.  Here is the description 
from PostgreSQL:

Table:
(http://www.postgresql.org/docs/view.php?version=7.3&idoc=1&file=sql-createtable.html)

  CREATE [ [ LOCAL ] { TEMPORARY | TEMP } ] TABLE table_name (
      { column_name data_type [ DEFAULT default_expr ] 
         [ column_constraint [, ... ] ]
      | table_constraint }  [, ... ]
  )
  [ INHERITS ( parent_table [, ... ] ) ]
  [ WITH OIDS | WITHOUT OIDS ]
  
  where column_constraint is:
  
  [ CONSTRAINT constraint_name ]
  { NOT NULL | NULL | UNIQUE | PRIMARY KEY |
    CHECK (expression) |
    REFERENCES reftable [ ( refcolumn ) ] [ MATCH FULL | MATCH PARTIAL ]
      [ ON DELETE action ] [ ON UPDATE action ] }
  [ DEFERRABLE | NOT DEFERRABLE ] 
  [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
  
  and table_constraint is:
  
  [ CONSTRAINT constraint_name ]
  { UNIQUE ( column_name [, ... ] ) |
    PRIMARY KEY ( column_name [, ... ] ) |
    CHECK ( expression ) |
    FOREIGN KEY ( column_name [, ... ] ) 
     REFERENCES reftable [ ( refcolumn [, ... ] ) ]
      [ MATCH FULL | MATCH PARTIAL ] 
      [ ON DELETE action ] [ ON UPDATE action ] }
  [ DEFERRABLE | NOT DEFERRABLE ] 
  [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]

Index:
(http://www.postgresql.org/docs/view.php?version=7.3&idoc=1&file=sql-createindex.html)

  CREATE [ UNIQUE ] INDEX index_name ON table
      [ USING acc_method ] ( column [ ops_name ] [, ...] )
      [ WHERE predicate ]
  CREATE [ UNIQUE ] INDEX index_name ON table
      [ USING acc_method ] ( func_name( column [, ... ]) [ ops_name ] )
      [ WHERE predicate ]

Alter table:

  ALTER TABLE [ ONLY ] table [ * ]
      ADD [ COLUMN ] column type [ column_constraint [ ... ] ]
  ALTER TABLE [ ONLY ] table [ * ]
      ALTER [ COLUMN ] column { SET DEFAULT value | DROP DEFAULT }
  ALTER TABLE [ ONLY ] table [ * ]
      ALTER [ COLUMN ] column SET STATISTICS integer
  ALTER TABLE [ ONLY ] table [ * ]
      RENAME [ COLUMN ] column TO newcolumn
  ALTER TABLE table
      RENAME TO new_table
  ALTER TABLE table
      ADD table_constraint_definition
  ALTER TABLE [ ONLY ] table 
          DROP CONSTRAINT constraint { RESTRICT | CASCADE }
  ALTER TABLE table
          OWNER TO new_owner 

View table:

    CREATE [ OR REPLACE ] VIEW view [ ( column name list ) ] AS SELECT query

=cut

use strict;
use vars qw[ $DEBUG $VERSION $GRAMMAR @EXPORT_OK ];
$VERSION = sprintf "%d.%02d", q$Revision: 1.39 $ =~ /(\d+)\.(\d+)/;
$DEBUG   = 0 unless defined $DEBUG;

use Data::Dumper;
use Parse::RecDescent;
use Exporter;
use base qw(Exporter);

@EXPORT_OK = qw(parse);

# Enable warnings within the Parse::RecDescent module.
$::RD_ERRORS = 1; # Make sure the parser dies when it encounters an error
$::RD_WARN   = 1; # Enable warnings. This will warn on unused rules &c.
$::RD_HINT   = 1; # Give out hints to help fix problems.

my $parser; # should we do this?  There's no programmic way to 
            # change the grammar, so I think this is safe.

$GRAMMAR = q!

{ my ( %tables, $table_order, $field_order, @table_comments) }

#
# The "eofile" rule makes the parser fail if any "statement" rule
# fails.  Otherwise, the first successful match by a "statement" 
# won't cause the failure needed to know that the parse, as a whole,
# failed. -ky
#
startrule : statement(s) eofile { \%tables }

eofile : /^\Z/

statement : create
  | comment_on_table
  | comment_on_column
  | comment
  | alter
  | grant
  | revoke
  | drop
  | insert
  | connect
  | update
  | set
  | <error>

connect : /^\s*\\\connect.*\n/

set : /set/i /[^;]*/ ';'

revoke : /revoke/i WORD(s /,/) /on/i TABLE(?) table_name /from/i name_with_opt_quotes(s /,/) ';'
    {
        my $table_name = $item{'table_name'};
        push @{ $tables{ $table_name }{'permissions'} }, {
            type       => 'revoke',
            actions    => $item[2],
            users      => $item[7],
        }
    }

grant : /grant/i WORD(s /,/) /on/i TABLE(?) table_name /to/i name_with_opt_quotes(s /,/) ';'
    {
        my $table_name = $item{'table_name'};
        push @{ $tables{ $table_name }{'permissions'} }, {
            type       => 'grant',
            actions    => $item[2],
            users      => $item[7],
        }
    }

drop : /drop/i /[^;]*/ ';'

insert : /insert/i /[^;]*/ ';'

update : /update/i /[^;]*/ ';'

#
# Create table.
#
create : create_table table_name '(' create_definition(s /,/) ')' table_option(s?) ';'
    {
        my $table_name                       = $item{'table_name'};
        $tables{ $table_name }{'order'}      = ++$table_order;
        $tables{ $table_name }{'table_name'} = $table_name;

        if ( @table_comments ) {
            $tables{ $table_name }{'comments'} = [ @table_comments ];
            @table_comments = ();
        }

        my @constraints;
        for my $definition ( @{ $item[4] } ) {
            if ( $definition->{'supertype'} eq 'field' ) {
                my $field_name = $definition->{'name'};
                $tables{ $table_name }{'fields'}{ $field_name } = 
                    { %$definition, order => $field_order++ };
				
                for my $constraint ( @{ $definition->{'constraints'} || [] } ) {
                    $constraint->{'fields'} = [ $field_name ];
                    push @{ $tables{ $table_name }{'constraints'} },
                        $constraint;
                }
            }
            elsif ( $definition->{'supertype'} eq 'constraint' ) {
                push @{ $tables{ $table_name }{'constraints'} }, $definition;
            }
            elsif ( $definition->{'supertype'} eq 'index' ) {
                push @{ $tables{ $table_name }{'indices'} }, $definition;
            }
        }

        for my $option ( @{ $item[6] } ) {
            $tables{ $table_name }{'table_options(s?)'}{ $option->{'type'} } = 
                $option;
        }

        1;
    }

create : CREATE unique(?) /(index|key)/i index_name /on/i table_name using_method(?) '(' field_name(s /,/) ')' where_predicate(?) ';'
    {
        push @{ $tables{ $item{'table_name'} }{'indices'} },
            {
                name      => $item{'index_name'},
                supertype => $item{'unique'}[0] ? 'constraint' : 'index',
                type      => $item{'unique'}[0] ? 'unique'     : 'normal',
                fields    => $item[9],
                method    => $item{'using_method'}[0],
            }
        ;

    }

#
# Create anything else (e.g., domain, etc.)
#
create : CREATE WORD /[^;]+/ ';'
    { @table_comments = (); }

using_method : /using/i WORD { $item[2] }

where_predicate : /where/i /[^;]+/

create_definition : field
    | table_constraint
    | <error>

comment : /^\s*(?:#|-{2})(.*)\n/ 
    { 
        my $comment =  $item[1];
        $comment    =~ s/^\s*(#|-*)\s*//;
        $comment    =~ s/\s*$//;
        $return     = $comment;
        push @table_comments, $comment;
    }

comment_on_table : /comment/i /on/i /table/i table_name /is/i comment_phrase ';'
    {
        push @{ $tables{ $item{'table_name'} }{'comments'} }, $item{'comment_phrase'};
    }

comment_on_column : /comment/i /on/i /column/i column_name /is/i comment_phrase ';'
    {
        my $table_name = $item[4]->{'table'};
        my $field_name = $item[4]->{'field'};
        push @{ $tables{ $table_name }{'fields'}{ $field_name }{'comments'} }, 
            $item{'comment_phrase'};
    }

column_name : NAME '.' NAME
    { $return = { table => $item[1], field => $item[3] } }

comment_phrase : /'.*?'|NULL/ 
    { 
        my $val = $item[1] || '';
        $val =~ s/^'|'$//g;
        $return = $val;
    }

field : field_comment(s?) field_name data_type field_meta(s?) field_comment(s?)
    {
        my ( $default, @constraints, $is_pk );
        my $is_nullable = 1;
        for my $meta ( @{ $item[4] } ) {
            if ( $meta->{'type'} eq 'default' ) {
                $default = $meta;
                next;
            }
            elsif ( $meta->{'type'} eq 'not_null' ) {
                $is_nullable = 0;
            }
            elsif ( $meta->{'type'} eq 'primary_key' ) {
                $is_pk = 1;
            }

            push @constraints, $meta if $meta->{'supertype'} eq 'constraint';
        }

        my @comments = ( @{ $item[1] }, @{ $item[5] } );

        $return = {
            supertype         => 'field',
            name              => $item{'field_name'}, 
            data_type         => $item{'data_type'}{'type'},
            size              => $item{'data_type'}{'size'},
            is_nullable       => $is_nullable,
            default           => $default->{'value'},
            constraints       => [ @constraints ],
            comments          => [ @comments ],
            is_primary_key    => $is_pk || 0,
            is_auto_increment => $item{'data_type'}{'is_auto_increment'},
        } 
    }
    | <error>

field_comment : /^\s*(?:#|-{2})(.*)\n/ 
    { 
        my $comment =  $item[1];
        $comment    =~ s/^\s*(#|-*)\s*//;
        $comment    =~ s/\s*$//;
        $return     = $comment;
    }

field_meta : default_val
    | column_constraint

column_constraint : constraint_name(?) column_constraint_type deferrable(?) deferred(?)
    {
        my $desc       = $item{'column_constraint_type'};
        my $type       = $desc->{'type'};
        my $fields     = $desc->{'fields'}     || [];
        my $expression = $desc->{'expression'} || '';

        $return              =  {
            supertype        => 'constraint',
            name             => $item{'constraint_name'}[0] || '',
            type             => $type,
            expression       => $type eq 'check' ? $expression : '',
            deferrable       => $item{'deferrable'},
            deferred         => $item{'deferred'},
            reference_table  => $desc->{'reference_table'},
            reference_fields => $desc->{'reference_fields'},
            match_type       => $desc->{'match_type'},
            on_delete_do     => $desc->{'on_delete_do'},
            on_update_do     => $desc->{'on_update_do'},
        } 
    }

constraint_name : /constraint/i name_with_opt_quotes { $item[2] }

column_constraint_type : /not null/i { $return = { type => 'not_null' } }
    |
    /null/i
        { $return = { type => 'null' } }
    |
    /unique/i
        { $return = { type => 'unique' } }
    |
    /primary key/i 
        { $return = { type => 'primary_key' } }
    |
    /check/i '(' /[^)]+/ ')' 
        { $return = { type => 'check', expression => $item[3] } }
    |
    /references/i table_name parens_word_list(?) match_type(?) key_action(s?)
    {
        my ( $on_delete, $on_update );
        for my $action ( @{ $item[5] || [] } ) {
            $on_delete = $action->{'action'} if $action->{'type'} eq 'delete';
            $on_update = $action->{'action'} if $action->{'type'} eq 'update';
        }

        $return              =  {
            type             => 'foreign_key',
            reference_table  => $item[2],
            reference_fields => $item[3][0],
            match_type       => $item[4][0],
            on_delete_do     => $on_delete,
            on_update_do     => $on_update,
        }
    }

table_name : name_with_opt_quotes

field_name : name_with_opt_quotes

name_with_opt_quotes : double_quote(?) NAME double_quote(?) { $item[2] }

double_quote: /"/

index_name : WORD

data_type : pg_data_type parens_value_list(?)
    { 
        my $data_type = $item[1];

        #
        # We can deduce some sizes from the data type's name.
        #
        if ( my $size = $item[2][0] ) {
            $data_type->{'size'} = $size;
        }

        $return  = $data_type;
    }

pg_data_type :
    /(bigint|int8)/i
        { 
            $return = { 
                type => 'integer',
                size => 20,
            };
        }
    |
    /(smallint|int2)/i
        { 
            $return = {
                type => 'integer', 
                size => 5,
            };
        }
    |
    /(integer|int4?)/i # interval must come before this
        { 
            $return = {
                type => 'integer', 
                size => 10,
            };
        }
    |    
    /(real|float4)/i
        { 
            $return = {
                type => 'real', 
                size => 10,
            };
        }
    |
    /(double precision|float8?)/i
        { 
            $return = {
                type => 'float', 
                size => 20,
            }; 
        }
    |
    /(bigserial|serial8)/i
        { 
            $return = { 
                type              => 'integer', 
                size              => 20, 
                is_auto_increment => 1,
            };
        }
    |
    /serial4?/i
        { 
            $return = { 
                type              => 'integer',
                size              => 11, 
                is_auto_increment => 1,
            };
        }
    |
    /(bit varying|varbit)/i
        { 
            $return = { type => 'varbit' };
        }
    |
    /character varying/i
        { 
            $return = { type => 'varchar' };
        }
    |
    /char(acter)?/i
        { 
            $return = { type => 'char' };
        }
    |
    /bool(ean)?/i
        { 
            $return = { type => 'boolean' };
        }
    |
    /bytea/i
        { 
            $return = { type => 'bytea' };
        }
    |
    /(timestamptz|timestamp)/i
        { 
            $return = { type => 'timestamp' };
        }
    |
    /text/i
        { 
            $return = { 
                type => 'text',
                size => 64_000,
            };
        }
    |
    /(bit|box|cidr|circle|date|inet|interval|line|lseg|macaddr|money|numeric|decimal|path|point|polygon|timetz|time|varchar)/i
        { 
            $return = { type => $item[1] };
        }

parens_value_list : '(' VALUE(s /,/) ')'
    { $item[2] }

parens_word_list : '(' WORD(s /,/) ')'
    { $item[2] }

field_size : '(' num_range ')' { $item{'num_range'} }

num_range : DIGITS ',' DIGITS
    { $return = $item[1].','.$item[3] }
    | DIGITS
    { $return = $item[1] }

table_constraint : comment(s?) constraint_name(?) table_constraint_type deferrable(?) deferred(?) comment(s?)
    {
        my $desc       = $item{'table_constraint_type'};
        my $type       = $desc->{'type'};
        my $fields     = $desc->{'fields'};
        my $expression = $desc->{'expression'};
        my @comments   = ( @{ $item[1] }, @{ $item[-1] } );

        $return              =  {
            name             => $item{'constraint_name'}[0] || '',
            supertype        => 'constraint',
            type             => $type,
            fields           => $type ne 'check' ? $fields : [],
            expression       => $type eq 'check' ? $expression : '',
            deferrable       => $item{'deferrable'},
            deferred         => $item{'deferred'},
            reference_table  => $desc->{'reference_table'},
            reference_fields => $desc->{'reference_fields'},
            match_type       => $desc->{'match_type'}[0],
            on_delete_do     => $desc->{'on_delete_do'},
            on_update_do     => $desc->{'on_update_do'},
            comments         => [ @comments ],
        } 
    }

table_constraint_type : /primary key/i '(' name_with_opt_quotes(s /,/) ')' 
    { 
        $return = {
            type   => 'primary_key',
            fields => $item[3],
        }
    }
    |
    /unique/i '(' name_with_opt_quotes(s /,/) ')' 
    { 
        $return    =  {
            type   => 'unique',
            fields => $item[3],
        }
    }
    |
    /check/i '(' /[^)]+/ ')' 
    {
        $return        =  {
            type       => 'check',
            expression => $item[3],
        }
    }
    |
    /foreign key/i '(' name_with_opt_quotes(s /,/) ')' /references/i table_name parens_word_list(?) match_type(?) key_action(s?)
    {
        my ( $on_delete, $on_update );
        for my $action ( @{ $item[9] || [] } ) {
            $on_delete = $action->{'action'} if $action->{'type'} eq 'delete';
            $on_update = $action->{'action'} if $action->{'type'} eq 'update';
        }
        
        $return              =  {
            supertype        => 'constraint',
            type             => 'foreign_key',
            fields           => $item[3],
            reference_table  => $item[6],
            reference_fields => $item[7][0],
            match_type       => $item[8][0],
            on_delete_do     => $on_delete || '',
            on_update_do     => $on_update || '',
        }
    }

deferrable : /not/i /deferrable/i 
    { 
        $return = ( $item[1] =~ /not/i ) ? 0 : 1;
    }

deferred : /initially/i /(deferred|immediate)/i { $item[2] }

match_type : /match full/i { 'match_full' }
    |
    /match partial/i { 'match_partial' }

key_action : key_delete 
    |
    key_update

key_delete : /on delete/i key_mutation
    { 
        $return = { 
            type   => 'delete',
            action => $item[2],
        };
    }

key_update : /on update/i key_mutation
    { 
        $return = { 
            type   => 'update',
            action => $item[2],
        };
    }

key_mutation : /no action/i { $return = 'no_action' }
    |
    /restrict/i { $return = 'restrict' }
    |
    /cascade/i { $return = 'cascade' }
    |
    /set null/i { $return = 'set null' }
    |
    /set default/i { $return = 'set default' }

alter : alter_table table_name add_column field ';' 
    { 
        my $field_def = $item[4];
        $tables{ $item[2] }{'fields'}{ $field_def->{'name'} } = {
            %$field_def, order => $field_order++
        };
        1;
    }

alter : alter_table table_name ADD table_constraint ';' 
    { 
        my $table_name = $item[2];
        my $constraint = $item[4];
        push @{ $tables{ $table_name }{'constraints'} }, $constraint;
        1;
    }

alter : alter_table table_name drop_column NAME restrict_or_cascade(?) ';' 
    {
        $tables{ $item[2] }{'fields'}{ $item[4] }{'drop'} = 1;
        1;
    }

alter : alter_table table_name alter_column NAME alter_default_val ';' 
    {
        $tables{ $item[2] }{'fields'}{ $item[4] }{'default'} = 
            $item[5]->{'value'};
        1;
    }

#
# These will just parse for now but won't affect the structure. - ky
#
alter : alter_table table_name /rename/i /to/i NAME ';'
    { 1 }

alter : alter_table table_name alter_column NAME SET /statistics/i INTEGER ';' 
    { 1 }

alter : alter_table table_name alter_column NAME SET /storage/i storage_type ';'
    { 1 }

alter : alter_table table_name rename_column NAME /to/i NAME ';'
    { 1 }

alter : alter_table table_name DROP /constraint/i NAME restrict_or_cascade ';'
    { 1 }

alter : alter_table table_name /owner/i /to/i NAME ';'
    { 1 }

storage_type : /(plain|external|extended|main)/i

alter_default_val : SET default_val 
    { 
        $return = { value => $item[2]->{'value'} } 
    }
    | DROP DEFAULT 
    { 
        $return = { value => undef } 
    } 

#
# This is a little tricky to get right, at least WRT to making the 
# tests pass.  The problem is that the constraints are stored just as
# a list (no name access), and the tests expect the constraints in a
# particular order.  I'm going to leave the rule but disable the code 
# for now. - ky
#
alter : alter_table table_name alter_column NAME alter_nullable ';'
    {
#        my $table_name  = $item[2];
#        my $field_name  = $item[4];
#        my $is_nullable = $item[5]->{'is_nullable'};
#
#        $tables{ $table_name }{'fields'}{ $field_name }{'is_nullable'} = 
#            $is_nullable;
#
#        if ( $is_nullable ) {
#            1;
#            push @{ $tables{ $table_name }{'constraints'} }, {
#                type   => 'not_null',
#                fields => [ $field_name ],
#            };
#        }
#        else {
#            for my $i ( 
#                0 .. $#{ $tables{ $table_name }{'constraints'} || [] } 
#            ) {
#                my $c = $tables{ $table_name }{'constraints'}[ $i ] or next;
#                my $fields = join( '', @{ $c->{'fields'} || [] } ) or next;
#                if ( $c->{'type'} eq 'not_null' && $fields eq $field_name ) {
#                    delete $tables{ $table_name }{'constraints'}[ $i ];
#                    last;
#                }
#            }
#        }

        1;
    }

alter_nullable : SET not_null 
    { 
        $return = { is_nullable => 0 } 
    }
    | DROP not_null
    { 
        $return = { is_nullable => 1 } 
    }

not_null : /not/i /null/i

add_column : ADD COLUMN(?)

alter_table : ALTER TABLE ONLY(?)

drop_column : DROP COLUMN(?)

alter_column : ALTER COLUMN(?)

rename_column : /rename/i COLUMN(?)

restrict_or_cascade : /restrict/i | 
    /cascade/i

#
# End basically useless stuff. - ky
#

create_table : CREATE TABLE

create_index : CREATE /index/i

default_val  : DEFAULT /(\d+|'[^']*'|\w+\(.*?\))|\w+/
    { 
        my $val =  defined $item[2] ? $item[2] : '';
        $val    =~ s/^'|'$//g; 
        $return =  {
            supertype => 'constraint',
            type      => 'default',
            value     => $val,
        }
    }
    | /null/i
    { 
        $return =  {
            supertype => 'constraint',
            type      => 'default',
            value     => 'NULL',
        }
    }

name_with_opt_paren : NAME parens_value_list(s?)
    { $item[2][0] ? "$item[1]($item[2][0][0])" : $item[1] }

unique : /unique/i { 1 }

key : /key/i | /index/i

table_option : /inherits/i '(' name_with_opt_quotes(s /,/) ')'
    { 
        $return = { type => 'inherits', table_name => $item[3] }
    }
    |
    /with(out)? oids/i
    {
        $return = { type => $item[1] =~ /out/i ? 'without_oids' : 'with_oids' }
    }

ADD : /add/i

ALTER : /alter/i

CREATE : /create/i

ONLY : /only/i

DEFAULT : /default/i

DROP : /drop/i

COLUMN : /column/i

TABLE : /table/i

SEMICOLON : /\s*;\n?/

INTEGER : /\d+/

WORD : /\w+/

DIGITS : /\d+/

COMMA : ','

SET : /set/i

NAME    : "`" /\w+/ "`"
    { $item[2] }
    | /\w+/
    { $item[1] }
    | /[\$\w]+/
    { $item[1] }

VALUE   : /[-+]?\.?\d+(?:[eE]\d+)?/
    { $item[1] }
    | /'.*?'/   # XXX doesn't handle embedded quotes
    { $item[1] }
    | /null/i
    { 'NULL' }

!;

# -------------------------------------------------------------------
sub parse {
    my ( $translator, $data ) = @_;
    $parser ||= Parse::RecDescent->new($GRAMMAR);

    $::RD_TRACE  = $translator->trace ? 1 : undef;
    $DEBUG       = $translator->debug;

    unless (defined $parser) {
        return $translator->error("Error instantiating Parse::RecDescent ".
            "instance: Bad grammer");
    }

    my $result = $parser->startrule($data);
    die "Parse failed.\n" unless defined $result;
    warn Dumper($result) if $DEBUG;

    my $schema = $translator->schema;
    my @tables = sort { 
        $result->{ $a }->{'order'} <=> $result->{ $b }->{'order'}
    } keys %{ $result };

    for my $table_name ( @tables ) {
        my $tdata =  $result->{ $table_name };
        my $table =  $schema->add_table( 
            name  => $tdata->{'table_name'},
        ) or die "Couldn't create table '$table_name': " . $schema->error;

        $table->comments( $tdata->{'comments'} );

        my @fields = sort { 
            $tdata->{'fields'}->{ $a }->{'order'} 
            <=>
            $tdata->{'fields'}->{ $b }->{'order'}
        } keys %{ $tdata->{'fields'} };

        for my $fname ( @fields ) {
            my $fdata = $tdata->{'fields'}{ $fname };
            next if $fdata->{'drop'};
            my $field = $table->add_field(
                name              => $fdata->{'name'},
                data_type         => $fdata->{'data_type'},
                size              => $fdata->{'size'},
                default_value     => $fdata->{'default'},
                is_auto_increment => $fdata->{'is_auto_increment'},
                is_nullable       => $fdata->{'is_nullable'},
                comments          => $fdata->{'comments'},
            ) or die $table->error;

            $table->primary_key( $field->name ) if $fdata->{'is_primary_key'};

            for my $cdata ( @{ $fdata->{'constraints'} } ) {
                next unless $cdata->{'type'} eq 'foreign_key';
                $cdata->{'fields'} ||= [ $field->name ];
                push @{ $tdata->{'constraints'} }, $cdata;
            }
        }

        for my $idata ( @{ $tdata->{'indices'} || [] } ) {
            my $index  =  $table->add_index(
                name   => $idata->{'name'},
                type   => uc $idata->{'type'},
                fields => $idata->{'fields'},
            ) or die $table->error;
        }

        for my $cdata ( @{ $tdata->{'constraints'} || [] } ) {
            my $constraint       =  $table->add_constraint(
                name             => $cdata->{'name'},
                type             => $cdata->{'type'},
                fields           => $cdata->{'fields'},
                reference_table  => $cdata->{'reference_table'},
                reference_fields => $cdata->{'reference_fields'},
                match_type       => $cdata->{'match_type'} || '',
                on_delete        => $cdata->{'on_delete_do'},
                on_update        => $cdata->{'on_update_do'},
                expression       => $cdata->{'expression'},
            ) or die "Can't add constraint of type '" .
                $cdata->{'type'} .  "' to table '" . $table->name . 
                "': " . $table->error;
        }
    }

    return 1;
}

1;

# -------------------------------------------------------------------
# Rescue the drowning and tie your shoestrings.
# Henry David Thoreau 
# -------------------------------------------------------------------

=pod

=head1 AUTHORS

Ken Y. Clark E<lt>kclark@cpan.orgE<gt>,
Allen Day E<lt>allenday@ucla.eduE<gt>.

=head1 SEE ALSO

perl(1), Parse::RecDescent.

=cut