package DBIx::Custom;

our $VERSION = '0.1635';

use 5.008001;

use strict;

use warnings;

use base 'Object::Simple';

use Carp 'croak';

use DBI;

use DBIx::Custom::Result;

use DBIx::Custom::Query;

use DBIx::Custom::QueryBuilder;

use DBIx::Custom::Where;

use Encode qw/encode_utf8 decode_utf8/;

__PACKAGE__->attr(

    [qw/data_source dbh password user/],

    dbi_options => sub { {} },

    cache => 1,

    filters => sub {

        {

            encode_utf8 => sub { encode_utf8($_[0]) },

            decode_utf8 => sub { decode_utf8($_[0]) }

        }

    },

    filter_check  => 1,

    query_builder => sub {DBIx::Custom::QueryBuilder->new},

    result_class  => 'DBIx::Custom::Result',

    table_class   => 'DBIx::Custom::Table'

);

# DBI methods

foreach my $method (qw/begin_work commit rollback/) {

    my $code = sub {

        my $self = shift;

        my $ret = eval {$self->dbh->$method};

        croak $@ if $@;

        return $ret;

    };

    no strict 'refs';

    my $pkg = __PACKAGE__;

    *{"${pkg}::$method"} = $code;

};

our $AUTOLOAD;

sub AUTOLOAD {

    my $self = shift;

    # Method

    my ($package, $method) = $AUTOLOAD =~ /^([\w\:]+)\:\:(\w+)$/;

    # Helper

    $self->{_helpers} ||= {};

    croak qq/Can't locate object method "$method" via "$package"/

      unless my $helper = $self->{_helpers}->{$method};

    # Run

    return $self->$helper(@_);

}

sub apply_filter {

    my $self = shift;

    $self->{filter} ||= {};

    # Table and column informations

    my ($table, @cs) = @_;

    if (@cs) {

        # Initialize filters

        $self->{filter}{out} ||= {};

        $self->{filter}{in} ||= {};

        # Create filters

        for (my $i = 0; $i < @cs; $i += 2) {

            # Column

            my $column = $cs[$i];

            # Filter

            my $filter = $cs[$i + 1] || {};

            my $in_filter = delete $filter->{in};

            my $out_filter = delete $filter->{out};

            croak "Usage \$dbi->apply_filter(" .

                  "TABLE, COLUMN, {in => INFILTER, out => OUTFILTER}, ...)"

              if ref $filter ne 'HASH' || keys %$filter;

            # Out filter

            if (ref $out_filter eq 'CODE') {

                $self->{filter}{out}{$table}{$column}

                  = $out_filter;

                $self->{filter}{out}{$table}{"$table.$column"}

                  = $out_filter;

            }

            elsif (defined $out_filter) {

                croak qq{"$out_filter" is not registered}

                  unless exists $self->filters->{$out_filter};

                $self->{filter}{out}{$table}{$column}

                  = $self->filters->{$out_filter};

                $self->{filter}{out}{$table}{"$table.$column"}

                  = $self->filters->{$out_filter};

            }

            # In filter

            if (ref $in_filter eq 'CODE') {

                $self->{filter}{in}{$table}{$column}

                  = $in_filter;

                $self->{filter}{in}{$table}{"$table.$column"}

                  = $in_filter;

            }

            elsif (defined $in_filter) {

                croak qq{"$in_filter" is not registered}

                  unless exists $self->filters->{$in_filter};

                $self->{filter}{in}{$table}{$column}

                  = $self->filters->{$in_filter};

                $self->{filter}{in}{$table}{"$table.$column"}

                  = $self->filters->{$in_filter};

            }

        }

        return $self;

    }

    return $self->{filter};

}

sub helper {

    my $self = shift;

    # Merge

    my $helpers = ref $_[0] eq 'HASH' ? $_[0] : {@_};

    $self->{_helpers} = {%{$self->{_helpers} || {}}, %$helpers};

    return $self;

}

sub connect {

    my $proto = shift;

    my $self;

    # Create

    if (my $class = ref $proto) {

        my $args = ref $_[0] eq 'HASH' ? $_[0] : {@_};

        $self = $proto;

        foreach my $attr (keys %$args) {

            $self->{$attr} = $args->{$attr};

        }

        # Check attribute names

        my @attrs = keys %$self;

        foreach my $attr (@attrs) {

            croak qq{"$attr" is invalid attribute name}

              unless $self->can($attr);

        }

    }

    else {

        $self = $proto->SUPER::new(@_);

    }

    # Information

    my $data_source = $self->data_source;

    croak qq{"data_source" must be specified to connect method"}

      unless $data_source;

    my $user        = $self->user;

    my $password    = $self->password;

    my $dbi_options = $self->dbi_options || {};

    # Connect

    my $dbh = eval {DBI->connect(

        $data_source,

        $user,

        $password,

        {

            RaiseError => 1,

            PrintError => 0,

            AutoCommit => 1,

            %$dbi_options

        }

    )};

    # Connect error

    croak $@ if $@;

    # Database handle

    $self->dbh($dbh);

    return $self;

}

sub create_query {

    my ($self, $source) = @_;

    # Cache

    my $cache = $self->cache;

    # Create query

    my $query;

    if ($cache) {

        # Get query

        my $q = $self->cache_method->($self, $source);

        # Create query

        $query = DBIx::Custom::Query->new($q) if $q;

    }

    unless ($query) {

        # Create SQL object

        my $builder = $self->query_builder;

        # Create query

        $query = $builder->build_query($source);

        # Cache query

        $self->cache_method->($self, $source,

                             {sql     => $query->sql, 

                              columns => $query->columns})

          if $cache;

    }

    # Prepare statement handle

    my $sth;

    eval { $sth = $self->dbh->prepare($query->{sql})};

    $self->_croak($@, qq{. SQL: "$query->{sql}"}) if $@;

    # Set statement handle

    $query->sth($sth);

    return $query;

}

our %VALID_DELETE_ARGS

  = map { $_ => 1 } qw/table where append filter allow_delete_all query/;

sub delete {

    my ($self, %args) = @_;

    # Check arguments

    foreach my $name (keys %args) {

        croak qq{"$name" is invalid argument}

          unless $VALID_DELETE_ARGS{$name};

    }

    # Arguments

    my $table            = $args{table} || '';

    croak qq{"table" option must be specified} unless $table;

    my $where            = $args{where} || {};

    my $append = $args{append};

    my $filter           = $args{filter};

    my $allow_delete_all = $args{allow_delete_all};

    # Where keys

    my @where_keys = keys %$where;

    # Not exists where keys

    croak qq{"where" argument must be specified and } .

          qq{contains the pairs of column name and value}

      if !@where_keys && !$allow_delete_all;

    # Where clause

    my $where_clause = '';

    if (@where_keys) {

        $where_clause = 'where ';

        $where_clause .= "{= $_} and " for @where_keys;

        $where_clause =~ s/ and $//;

    }

    # Source of SQL

    my $source = "delete from $table $where_clause";

    $source .= " $append" if $append;

    # Create query

    my $query = $self->create_query($source);

    return $query if $args{query};

    # Execute query

    my $ret_val = $self->execute(

        $query, param  => $where, filter => $filter,

        table => $table);

    return $ret_val;

}

sub delete_all { shift->delete(allow_delete_all => 1, @_) }

sub DESTROY { }

our %VALID_EXECUTE_ARGS = map { $_ => 1 } qw/param filter table/;

sub execute{

    my ($self, $query, %args)  = @_;

    # Check arguments

    foreach my $name (keys %args) {

        croak qq{"$name" is invalid argument}

          unless $VALID_EXECUTE_ARGS{$name};

    }

    my $params = $args{param} || {};

    # First argument is the soruce of SQL

    $query = $self->create_query($query)

      unless ref $query;

    # Auto filter

    my $filter = {};

    my $tables = $args{table} || [];

    $tables = [$tables]

      unless ref $tables eq 'ARRAY';

    foreach my $table (@$tables) {

        $filter = {

            %$filter,

            %{$self->{filter}{out}->{$table} || {}}

        }

    }

    # Filter argument

    my $f = $args{filter} || $query->filter || {};

    foreach my $column (keys %$f) {

        my $fname = $f->{$column};

        if (!defined $fname) {

            $f->{$column} = undef;

        }

        elsif (ref $fname ne 'CODE') {

          croak qq{"$fname" is not registered"}

            unless exists $self->filters->{$fname};

          $f->{$column} = $self->filters->{$fname};

        }

    }

    $filter = {%$filter, %$f};

    # Create bind values

    my $binds = $self->_build_binds($params, $query->columns, $filter);

    # Execute

    my $sth      = $query->sth;

    my $affected;

    eval {$affected = $sth->execute(@$binds)};

    $self->_croak($@) if $@;

    # Return resultset if select statement is executed

    if ($sth->{NUM_OF_FIELDS}) {

        # Auto in filter

        my $in_filter = {};

        foreach my $table (@$tables) {

            $in_filter = {

                %$in_filter,

                %{$self->{filter}{in}{$table} || {}}

            }

        }

        # Result

        my $result = $self->result_class->new(

            sth            => $sth,

            filters        => $self->filters,

            filter_check   => $self->filter_check,

            default_filter => $self->{default_in_filter},

            filter         => $in_filter || {}

        );

        return $result;

    }

    return $affected;

}

sub expand {

    my $self = shift;

    my $source = ref $_[0] eq 'HASH' ? $_[0] : {@_};

    my $table = (keys %$source)[0];

    my $param = $source->{$table};

    # Expand table name

    my $expand = {};

    foreach my $column (keys %$param) {

        $expand->{"$table.$column"} = $param->{$column};

    }

    return %$expand;

}

our %VALID_INSERT_ARGS = map { $_ => 1 } qw/table param append

                                            filter query/;

sub insert {

    my ($self, %args) = @_;

    # Check arguments

    foreach my $name (keys %args) {

        croak qq{"$name" is invalid argument}

          unless $VALID_INSERT_ARGS{$name};

    }

    # Arguments

    my $table  = $args{table};

    croak qq{"table" option must be specified} unless $table;

    my $param  = $args{param} || {};

    my $append = $args{append} || '';

    my $filter = $args{filter};

    # Insert keys

    my @insert_keys = keys %$param;

    # Templte for insert

    my $source = "insert into $table {insert_param "

               . join(' ', @insert_keys) . '}';

    $source .= " $append" if $append;

    # Create query

    my $query = $self->create_query($source);

    return $query if $args{query};

    # Execute query

    my $ret_val = $self->execute(

        $query,

        param  => $param,

        filter => $filter,

        table => $table

    );

    return $ret_val;

}

sub each_column {

    my ($self, $cb) = @_;

    # Iterate all tables

    my $sth_tables = $self->dbh->table_info;

    while (my $table_info = $sth_tables->fetchrow_hashref) {

        # Table

        my $table = $table_info->{TABLE_NAME};

        # Iterate all columns

        my $sth_columns = $self->dbh->column_info(undef, undef, $table, '%');

        while (my $column_info = $sth_columns->fetchrow_hashref) {

            my $column = $column_info->{COLUMN_NAME};

            $cb->($table, $column, $column_info);

        }

    }

}

sub new {

    my $self = shift->SUPER::new(@_);

    # Check attribute names

    my @attrs = keys %$self;

    foreach my $attr (@attrs) {

        croak qq{"$attr" is invalid attribute name}

          unless $self->can($attr);

    }

    return $self;

}

sub register_filter {

    my $invocant = shift;

    # Register filter

    my $filters = ref $_[0] eq 'HASH' ? $_[0] : {@_};

    $invocant->filters({%{$invocant->filters}, %$filters});

    return $invocant;

}

sub register_tag_processor {

    return shift->query_builder->register_tag_processor(@_);

}

our %VALID_SELECT_ARGS

  = map { $_ => 1 } qw/table column where append relation filter query/;

sub select {

    my ($self, %args) = @_;

    # Check arguments

    foreach my $name (keys %args) {

        croak qq{"$name" is invalid argument}

          unless $VALID_SELECT_ARGS{$name};

    }

    # Arguments

    my $table = $args{table};

    my $tables = ref $table eq 'ARRAY' ? $table

               : defined $table ? [$table]

               : [];

    croak qq{"table" option must be specified} unless @$tables;

    my $columns  = $args{column} || [];

    my $where    = $args{where};

    my $relation = $args{relation};

    my $append   = $args{append};

    my $filter   = $args{filter};

    # Source of SQL

    my $source = 'select ';

    # Column clause

    if (@$columns) {

        foreach my $column (@$columns) {

            $source .= "$column, ";

        }

        $source =~ s/, $/ /;

    }

    else {

        $source .= '* ';

    }

    # Table

    $source .= 'from ';

    foreach my $table (@$tables) {

        $source .= "$table, ";

    }

    $source =~ s/, $/ /;

    # Where clause

    my $param;

    my $wexists;

    if (ref $where eq 'HASH') {

        $param = $where;

        $wexists = keys %$where;

        if ($wexists) {

            $source .= 'where (';

            foreach my $where_key (keys %$where) {

                $source .= "{= $where_key} and ";

            }

            $source =~ s/ and $//;

            $source .= ') ';

        }

    }

    elsif (ref $where eq 'ARRAY') {

        my $w = $where->[0] || '';

        $param = $where->[1];

        $wexists = $w =~ /\S/;

        $source .= "where ($w) " if $wexists;

    }

    elsif (ref $where eq 'DBIx::Custom::Where') {

        $param = $where->param;

        my $w = $where->to_string;

        $wexists = $w =~ /\S/;

        $source .= $w;

    }

    # Relation

    if ($relation) {

        $source .= $wexists ? "and " : "where ";

        foreach my $rkey (keys %$relation) {

            $source .= "$rkey = " . $relation->{$rkey} . " and ";

        }

    }

    $source =~ s/ and $//;

    # Append some statement

    $source .= " $append" if $append;

    # Create query

    my $query = $self->create_query($source);

    return $query if $args{query};

    # Execute query

    my $result = $self->execute(

        $query, param  => $param, filter => $filter,

        table => $tables);    

    return $result;

}

sub table {

    my $self = shift;

    my $name = shift;

    # Table class

    my $table_class = $self->table_class;

    croak qq{Invalid table class name "$table_class"}

      unless $table_class =~ /^[\w:]+$/;

    unless ($table_class->can('isa')) {

        eval "require $table_class";

        croak $@ if $@;

    }

    # Create table

    $self->{_tables} ||= {};

    $self->{_tables}->{$name}

        = $table_class->new(name => $name, dbi => $self)

      unless defined $self->{_tables}->{$name};

    # Helper

    $self->{_tables}->{$name}->helper(@_) if @_;

    return $self->{_tables}{$name};

}

sub txn_scope {

    my $self = shift;

    require DBIx::TransactionManager;

    $self->{_transaction_manager}

      ||= DBIx::TransactionManager->new($self->dbh);

    return $self->{_transaction_manager}->txn_scope;

}

our %VALID_UPDATE_ARGS

  = map { $_ => 1 } qw/table param

                       where append filter allow_update_all query/;

sub update {

    my ($self, %args) = @_;

    # Check arguments

    foreach my $name (keys %args) {

        croak qq{"$name" is invalid argument}

          unless $VALID_UPDATE_ARGS{$name};

    }

    # Arguments

    my $table            = $args{table} || '';

    croak qq{"table" option must be specified} unless $table;

    my $param            = $args{param} || {};

    my $where            = $args{where} || {};

    my $append = $args{append} || '';

    my $filter           = $args{filter};

    my $allow_update_all = $args{allow_update_all};

    # Update keys

    my @update_keys = keys %$param;

    # Where keys

    my @where_keys = keys %$where;

    # Not exists where keys

    croak qq{"where" argument must be specified and } .

          qq{contains the pairs of column name and value}

      if !@where_keys && !$allow_update_all;

    # Update clause

    my $update_clause = '{update_param ' . join(' ', @update_keys) . '}';

    # Where clause

    my $where_clause = '';

    my $new_where = {};

    if (@where_keys) {

        $where_clause = 'where ';

        $where_clause .= "{= $_} and " for @where_keys;

        $where_clause =~ s/ and $//;

    }

    # Source of SQL

    my $source = "update $table $update_clause $where_clause";

    $source .= " $append" if $append;

    # Rearrange parameters

    foreach my $wkey (@where_keys) {

        if (exists $param->{$wkey}) {

            $param->{$wkey} = [$param->{$wkey}]

              unless ref $param->{$wkey} eq 'ARRAY';

            push @{$param->{$wkey}}, $where->{$wkey};

        }

        else {

            $param->{$wkey} = $where->{$wkey};

        }

    }

    # Create query

    my $query = $self->create_query($source);

    return $query if $args{query};

    # Execute query

    my $ret_val = $self->execute($query, param  => $param, 

                                 filter => $filter,

                                 table => $table);

    return $ret_val;

}

sub update_all { shift->update(allow_update_all => 1, @_) };

sub where { DBIx::Custom::Where->new(

              query_builder => shift->query_builder) }

sub _build_binds {

    my ($self, $params, $columns, $filter) = @_;

    # bind values

    my @binds;

    # Build bind values

    my $count = {};

    foreach my $column (@$columns) {

        # Value

        my $value = ref $params->{$column} eq 'ARRAY'

                  ? $params->{$column}->[$count->{$column} || 0]

                  : $params->{$column};

        # Filter

        my $f = $filter->{$column} || $self->{default_out_filter} || '';

        push @binds, $f ? $f->($value) : $value;

        # Count up 

        $count->{$column}++;

    }

    return \@binds;

}

sub _croak {

    my ($self, $error, $append) = @_;

    $append ||= "";

    # Verbose

    if ($Carp::Verbose) { croak $error }

    # Not verbose

    else {

        # Remove line and module infromation

        my $at_pos = rindex($error, ' at ');

        $error = substr($error, 0, $at_pos);

        $error =~ s/\s+$//;

        croak "$error$append";

    }

}

# Deprecated

__PACKAGE__->attr(cache_method => sub {

    sub {

        my $self = shift;

        $self->{_cached} ||= {};

        if (@_ > 1) {

            $self->{_cached}{$_[0]} = $_[1] 

        }

        else {

            return $self->{_cached}{$_[0]}

        }

    }

});

sub default_bind_filter {

    my $self = shift;

    if (@_) {

        my $fname = $_[0];

        if (@_ && !$fname) {

            $self->{default_out_filter} = undef;

        }

        else {

            croak qq{"$fname" is not registered}

              unless exists $self->filters->{$fname};

            $self->{default_out_filter} = $self->filters->{$fname};

        }

        return $self;

    }

    return $self->{default_out_filter};

}

sub default_fetch_filter {

    my $self = shift;

    my $fname = $_[0];

    if (@_) {

        if (@_ && !$fname) {

            $self->{default_in_filter} = undef;

        }

        else {

            croak qq{"$fname" is not registered}

              unless exists $self->filters->{$fname};

            $self->{default_in_filter} = $self->filters->{$fname};

        }

        return $self;

    }

    return $self->{default_in_filter}

}

1;

=head1 NAME

DBIx::Custom - DBI interface, having hash parameter binding and filtering system

=head1 SYNOPSYS

Connect to the database.

    use DBIx::Custom;

    my $dbi = DBIx::Custom->connect(data_source => "dbi:mysql:database=dbname",

                                    user => 'ken', password => '!LFKD%$&');

Insert, update, and delete

    # Insert 

    $dbi->insert(table  => 'book',

                 param  => {title => 'Perl', author => 'Ken'},

                 filter => {title => 'encode_utf8'});

    # Update 

    $dbi->update(table  => 'book', 

                 param  => {title => 'Perl', author => 'Ken'}, 

                 where  => {id => 5},

                 filter => {title => 'encode_utf8'});

    # Update all

    $dbi->update_all(table  => 'book',

                     param  => {title => 'Perl'},

                     filter => {title => 'encode_utf8'});

    # Delete

    $dbi->delete(table  => 'book',

                 where  => {author => 'Ken'},

                 filter => {title => 'encode_utf8'});

    # Delete all

    $dbi->delete_all(table => 'book');

Select

    # Select

    my $result = $dbi->select(table => 'book');

    # Select, more complex

    my $result = $dbi->select(

        table  => 'book',

        column => [qw/author title/],

        where  => {author => 'Ken'},

        append => 'order by id limit 5',

        filter => {title => 'encode_utf8'}

    );

    # Select, join table

    my $result = $dbi->select(

        table    => ['book', 'rental'],

        column   => ['book.name as book_name']

        relation => {'book.id' => 'rental.book_id'}

    );

    # Select, more flexible where

    my $result = $dbi->select(

        table  => 'book',

        where  => ['{= author} and {like title}', 

                   {author => 'Ken', title => '%Perl%'}]

    );

Execute SQL

    # Execute SQL

    $dbi->execute("select title from book");

    # Execute SQL with hash binding and filtering

    $dbi->execute("select id from book where {= author} and {like title}",

                  param  => {author => 'ken', title => '%Perl%'},

                  filter => {title => 'encode_utf8'});

    # Create query and execute it

    my $query = $dbi->create_query(

        "select id from book where {= author} and {like title}"

    );

    $dbi->execute($query, param => {author => 'Ken', title => '%Perl%'})

Other features.

    # Get DBI object

    my $dbh = $dbi->dbh;

Fetch row.

    # Fetch

    while (my $row = $result->fetch) {

        # ...

    }

    # Fetch hash

    while (my $row = $result->fetch_hash) {

    }

=head1 DESCRIPTIONS

L<DBIx::Custom> is one of L<DBI> interface modules,

such as L<DBIx::Class>, L<DBIx::Simple>.

This module is not O/R mapper. O/R mapper is useful,

but you must learn many syntax of the O/R mapper,

which is almost another language.

Created SQL statement is offten not effcient and damage SQL performance.

so you have to execute raw SQL in the end.

L<DBIx::Custom> is middle area between L<DBI> and O/R mapper.

L<DBIx::Custom> provide flexible hash parameter binding and filtering system,

and suger methods, such as C<insert()>, C<update()>, C<delete()>, C<select()>

to execute SQL easily.

L<DBIx::Custom> respects SQL. SQL is very complex and not beautiful,

but de-facto standard,

so all people learing database know it.

If you already know SQL,

you learn a little thing to use L<DBIx::Custom>.

See L<DBIx::Custom::Guide> for more details.

=head1 GUIDE

L<DBIx::Custom::Guide> - L<DBIx::Custom> complete guide

=head1 EXAMPLES

L<DBIx::Custom Wiki|https://github.com/yuki-kimoto/DBIx-Custom/wiki> - Many useful examples

=head1 ATTRIBUTES

=head2 C<cache>

    my $cache = $dbi->cache;

    $dbi      = $dbi->cache(1);

Enable parsed L<DBIx::Custom::Query> object caching.

Default to 1.

=head2 C<data_source>

    my $data_source = $dbi->data_source;

    $dbi            = $dbi->data_source("DBI:mysql:database=dbname");

Data source.

C<connect()> method use this value to connect the database.

=head2 C<dbh>

    my $dbh = $dbi->dbh;

    $dbi    = $dbi->dbh($dbh);

L<DBI> object. You can call all methods of L<DBI>.

=head2 C<dbi_options>

    my $dbi_options = $dbi->dbi_options;

    $dbi            = $dbi->dbi_options($dbi_options);

DBI options.

C<connect()> method use this value to connect the database.

Default filter when row is fetched.

=head2 C<filters>

    my $filters = $dbi->filters;

    $dbi        = $dbi->filters(\%filters);

Filter functions.

"encode_utf8" and "decode_utf8" is registered by default.

=head2 C<filter_check>

    my $filter_check = $dbi->filter_check;

    $dbi             = $dbi->filter_check(0);

B<this attribute is now deprecated and has no mean

because check is always done>. 

=head2 C<password>

    my $password = $dbi->password;

    $dbi         = $dbi->password('lkj&le`@s');

Password.

C<connect()> method use this value to connect the database.

=head2 C<query_builder>

    my $sql_class = $dbi->query_builder;

    $dbi          = $dbi->query_builder(DBIx::Custom::QueryBuilder->new);

SQL builder. C<query_builder()> must be 

the instance of L<DBIx::Custom::QueryBuilder> subclass.

Default to L<DBIx::Custom::QueryBuilder> object.

=head2 C<result_class>

    my $result_class = $dbi->result_class;

    $dbi             = $dbi->result_class('DBIx::Custom::Result');

Result class for select statement.

Default to L<DBIx::Custom::Result>.

=head2 C<user>

    my $user = $dbi->user;

    $dbi     = $dbi->user('Ken');

User name.

C<connect()> method use this value to connect the database.

=head1 METHODS

L<DBIx::Custom> inherits all methods from L<Object::Simple>

and implements the following new ones.

=head2 C<(experimental) apply_filter >

    $dbi->apply_filter(

        $table,

        $column1 => {in => $infilter1, out => $outfilter1}

        $column2 => {in => $infilter2, out => $outfilter2}

        ...,

    );

C<apply_filter> is automatically filter for columns of table.