package DBIx::Interp; use strict; use warnings; use Carp; #use DBI; use SQL::Interp ':all'; use base qw(Exporter DBI); our $VERSION = '1.02'; our @EXPORT; our %EXPORT_TAGS = (all => [qw( attr dbi_interp key_field )]); our @EXPORT_OK = @{$EXPORT_TAGS{all}}; our @CARP_NOT = qw(DBIx::Interp DBIx::Interp::db DBIx::Interp::STX); sub _wrap(&); sub import { my @params = @_; # handle local exports my @params2 = _wrap_params($SQL::Interp::EXPORT_TAGS{all}, [SQL::Interp::_use_params()], @params); __PACKAGE__->export_to_level(1, @params2); # pass use parameters to wrapped module. @_ = _wrap_params($EXPORT_TAGS{all}, [], @params); push @_, __WRAP => 1; goto &SQL::Interp::import; # @_ } # internal helper function to mangle "use" parameters for a wrapper # called only by import(). sub _wrap_params { my ($skip_names, $skip_keys, @parts) = @_; my @out; my %skip_names = map {($_=>1)} @$skip_names; my %skip_keys = map {($_=>1)} @$skip_keys; while (@parts) { if ($skip_names{$parts[0]}) { shift @parts; } elsif ( $skip_keys{$parts[0]}) { shift @parts; shift @parts; } else { push @out, shift @parts; } } return @out; } sub key_field { my $key = shift; return bless \$key, "DBIx::Interp::Key"; } sub attr { return bless {@_}, "DBIx::Interp::Attr"; } sub dbi_interp { return DBIx::Interp::db::dbi_interp(@_); } sub new { shift; return DBIx::Interp::db->new(@_); } sub _wrap(&) { my $code = shift; my $x; my @x; my $want = wantarray(); eval { if ($want) { @x = $code->(); } else { $x = $code->(); } }; if ($@) { croak $@; } return $want ? @x : $x; } ##### package DBIx::Interp::db; use strict; use warnings; use Carp; use base 'DBI::db'; use Scalar::Util 'weaken'; our @CARP_NOT = @DBIx::Interp::CARP_NOT; my $priv = 'private_DBIxInterpolate'; sub new { my $class = shift; my $dbh; if (UNIVERSAL::isa($_[0], 'DBI::db')) { $dbh = shift; } elsif (ref $_[0] eq 'ARRAY') { $dbh = DBI->connect(@{shift @_}); return if ! defined $dbh; } else { croak 'DBIx::Interp::db::new() not passed database connection'; } my $interp = SQL::Interp->new(($dbh || ()), @_); my $self = $dbh; bless $self, $class; my $private = $self->{$priv} = {}; $private->{stx} = $self->prepare_i(); $private->{interp} = $interp; # weaken circular references to allow garbage collection weaken $private->{stx}->{dbx}; weaken $private->{interp}->{dbh}; return $self; } #sub DESTROY { # my ($self) = @_; # $self->SUPER::DESTROY(); #} sub connect { my $class = shift; my $self; eval { my $dbh = DBI->connect(@_); return if ! $dbh; $self = DBIx::Interp->new($dbh); #Q: OK? }; if ($@) { croak $@; } return $self; } # removed in 0.40: #sub dbh # new in 0.31 sub stx { my $self = shift; return $self->{$priv}->{stx}; } # new in 0.40 sub interp { my $self = shift; return $self->{$priv}->{interp}; } sub dbi_interp { my $key; my $attr; my @args = grep { my $save = 1; if (ref($_) eq 'DBIx::Interp::Key') { $key = $_; $save = 0; } elsif (ref($_) eq 'DBIx::Interp::Attr') { $attr = {%$_}; $save = 0; } $save; } @_; my ($sql, @bind) = sql_interp(@args); my @params = ($sql); push @params, $$key if defined $key; push @params, $attr, @bind; return @params; } sub sql_interp { my (@params) = @_; if (UNIVERSAL::isa($_[0], 'DBIx::Interp::db')) { my $self = shift; return SQL::Interp::sql_interp($self->interp(), @_); } else { return SQL::Interp::sql_interp(@_); } } # based on function in DBI sub _do_selectrow_i { my ($self, $method, @list) = @_; #my $sth = $dbh->prepare($stmt, $attr) or return; #_do_execute($sth, @bind) or return; my $stx = $self->{$priv}->{stx}; $stx->execute_i(@list) or return; my $sth = $stx->sth(); my $row = $sth->$method() and $sth->finish; return $row; } # new in 0.40 sub prepare_i { my ($self) = @_; return DBIx::Interp::STX->new($self); } # new in 0.40 sub do_i { my ($self, @list) = @_; return _wrap { # based on DBI::do # my $sth = $dbh->prepare($sql, $attr) or return undef; # _do_execute(@bind) or return undef; my $stx = $self->{$priv}->{stx}; $stx->execute_i(@list) or return undef; my $sth = $stx->sth(); my $rows = $sth->rows; return ($rows == 0) ? "0E0" : $rows; }; } # new in 0.40 sub selectrow_array_i { my ($self, @list) = @_; my $want = wantarray; return _wrap { # based on DBI::selectrow_array my $row = $self->_do_selectrow_i('fetchrow_arrayref', @list) or return; return $row->[0] unless $want; return @$row; }; } # new in 0.40 sub selectrow_arrayref_i { my ($self, @list) = @_; return _wrap { # based on DBI::selectrow_arrayref return $self->_do_selectrow_i('fetchrow_arrayref', @list); }; } # new in 0.40 sub selectrow_hashref_i { my ($self, @list) = @_; return _wrap { # based on DBI::selectrow_hashref return $self->_do_selectrow_i('fetchrow_hashref', @list); }; } # new in 0.40 sub selectall_arrayref_i { my ($self, @list) = @_; return _wrap { # improve: no need to to a full dbi_interp call here and elsewhere my ($sql, $attr, @bind) = $self->dbi_interp(@list); # need $attr # based on DBI::selectall_arrayref # my $sth = $dbh->prepare($sql, $attr) or return; # _do_execute($sth, @bind) or return; my $stx = $self->{$priv}->{stx}; $stx->execute_i(@list) or return; my $sth = $stx->sth(); # typically undef, else hash or array ref my $slice = $attr->{Slice}; if (!$slice and $slice=$attr->{Columns}) { if (ref $slice eq 'ARRAY') { $slice = [ @{$attr->{Columns}} ]; for (@$slice) { $_-- } } } my $rows = $sth->fetchall_arrayref( $slice, my $MaxRows = $attr->{MaxRows}); $sth->finish if defined $MaxRows; return $rows; }; } # new in 0.40 sub selectall_hashref_i { my ($self, @list) = @_; return _wrap { #need $key_field my ($sql, $key_field, $attr, @bind) = $self->dbi_interp(@list); # based on DBI::selectall_hashref # my $sth = $dbh->prepare($sql, $attr); # return unless $sth; # _do_execute($sth, @bind) or return; my $stx = $self->{$priv}->{stx}; $stx->execute_i(@list) or return; my $sth = $stx->sth(); return $sth->fetchall_hashref($key_field); }; } # new in 0.40 sub selectcol_arrayref_i { my ($self, @list) = @_; return _wrap { my ($sql, $attr, @bind) = $self->dbi_interp(@list); # need $attr # based on DBI::selectcol_arrayref # my $sth = $dbh->prepare($sql, $attr); # return unless $sth; # _do_execute($sth, @bind) or return; my $stx = $self->{$priv}->{stx}; $stx->execute_i(@list) or return; my @columns = ($attr->{Columns}) ? @{$attr->{Columns}} : (1); my @values = (undef) x @columns; my $idx = 0; my $sth = $stx->sth(); for (@columns) { $sth->bind_col($_, \$values[$idx++]) or return; } my @col; if (my $max = $attr->{MaxRows}) { push @col, @values while @col<$max && $sth->fetch; } else { push @col, @values while $sth->fetch; } return \@col; }; } #old: sub _do_execute { # my ($sth, @bind) = @_; # if (ref($bind[0]) eq 'ARRAY') { # _bind_params($sth, @bind); # return $sth->execute(); # } # else { # return $sth->execute(@bind); # } #} #old: sub _bind_params { # my ($sth, @bind) = @_; # my $num = 1; # for my $val (@bind) { # $sth->bind_param($num++, $val->[0], $val->[1]->{type}); # } #} 1; ##### package DBIx::Interp::STX; use strict; use warnings; use Carp; our @CARP_NOT = @DBIx::Interp::CARP_NOT; sub new { my ($class, $dbx) = @_; my $self = bless { # active sth sth => undef, # map: SQL --> sth (sth cache) sths => {}, # queue of SQL. used to select sth to delete if cache is full sql_queue => [], # DBIx::Interp dbx => $dbx, # max sths allowed in the cache max_sths => 1 }, $class; return $self; } sub max_sths { my ($self, $max_sths) = @_; if (defined $max_sths) { $self->{max_sths} = $max_sths; } else { return $self->{max_sths}; } } sub sth { my $self = shift; return $self->{sth}; } sub sths { my $self = shift; return {%{$self->{sths}}}; } # renamed execute --> execute_i in 0.40 sub execute_i { my ($self, @list) = @_; return DBIx::Interp::_wrap { my ($sql, @bind) = $self->{dbx}->dbi_interp(@list); shift @bind if defined $bind[0] && ref $bind[0] eq ''; # remove any key_field() my $attr = shift @bind; my $sth = $self->{sths}->{$sql}; if (! defined $sth) { $sth = $self->{dbx}->prepare($sql, $attr) or return; if (@{$self->{sql_queue}} + 1 > $self->{max_sths}) { my $sql_remove = shift @{$self->{sql_queue}}; delete $self->{sths}->{$sql_remove}; } $self->{sths}->{$sql} = $sth; push @{$self->{sql_queue}}, $sql; } $self->{sth} = $sth; _bind_params($sth, @bind); return $sth->execute(); }; } sub _bind_params { my ($sth, @bind) = @_; my $num = 1; return DBIx::Interp::_wrap { if (ref($bind[0]) eq 'ARRAY') { for my $val (@bind) { $sth->bind_param($num++, $val->[0], $val->[1]->{type}); } } else { for my $val (@bind) { $sth->bind_param($num++, $val); } } }; } sub fetchrow_arrayref { my $self = shift; return DBIx::Interp::_wrap { return $self->{sth}->fetchrow_arrayref(); }; } sub fetchrow_array { my $self = shift; return DBIx::Interp::_wrap { return $self->{sth}->fetchrow_array(); }; } sub fetchrow_hashref { my ($self, @params) = @_; return DBIx::Interp::_wrap { return $self->{sth}->fetchrow_hashref(@params); }; } sub fetchall_arrayref { my ($self, @params) = @_; return DBIx::Interp::_wrap { return $self->{sth}->fetchall_arrayref(@params); }; } sub fetchall_hashref { my ($self, @params) = @_; return DBIx::Interp::_wrap { return $self->{sth}->fetchall_hashref(@params); }; } 1; __END__ =head1 NAME DBIx::Interp - Interpolate Perl variables into SQL with DBI =head1 SYNOPSIS use DBI; use DBIx::Interp ':all'; my $dbx = DBIx::Interp->new($dbh); my $rv = $dbx->do_i('INSERT INTO table', \%item); my $rv = $dbx->do_i('UPDATE table SET', \%item, 'WHERE item_id <> ', \2); my $rv = $dbx->do_i('DELETE FROM table WHERE item_id = ', \2); my $LoH = $dbx->selectall_arrayref_i(' SELECT * FROM table WHERE x = ', \$s, 'AND y IN', \@v ,attr(Slice=>{})); =head1 DESCRIPTION DBIx::Interp brings L<SQL::Interp|SQL::Interp> and L<DBI|DBI> together in a natural way. Please read the documentation of those two modules if you are unfamiliar with them. The DBIx::Interp interface adds methods to the DBI interface with an "_i" suffix, indicating that SQL::Interp interpolatation is performed in these cases. =head1 Helper Functions you may need =head2 C<attr> dbi_interp("SELECT * from my_table", attr( Slice => {} ) ); Creates and returns an DBIx::Interp::Attr object. When processed by L<dbi_interp()>, it will add the provided key/value pairs to the "%attrs" hash that is accepted by many DBI methods. =head2 C<key_field> $keyobj = key_field($key_field); Creates and returns an DBIx::Interp::Key object. When processed by L<dbi_interp()>, an extra C<$key_field> value will be returned in the result so that the result is suitable for passing into $dbh->fetchrow_hashref and related methods. my ($sql, $key, $attr, @bind) = my @params = dbi_interp "SELECT * FROM mytable", key_field('itemid'); $dbh->selectall_hashref(@params); =head1 Database object (DBX) methods An object of type DBIx::Interp represents (and wraps) a database handle. Most of its methods are wrappers around corresponding DBI methods. =over 4 =item C<new> (static method) my $dbx = DBX::Interpolate->new($db, %params); Creates a new object, creating or attaching a DBI handle. $db is either a DBI database handle or an ARRAYREF containing parameters that will be passed to DBI::connect, e.g. [$data_source, $username, $auth, \%attr]. This parameter may be omitted. Any additional %params are passed onto L<SQL::Interp::new|SQL::Interp/new>. =item C<connect> (static method) $dbx = DBIx::Interp->connect($data_source, $username, $auth, \%attr); Connects to a database. This is identical to DBI::connect except that it returns at DBIx::Interp object. An alternate way to connect or attach an existing DBI handle is via the C<new> method. =item C<dbh> $dbh = $dbx->dbh(); Returns the underlying DBI handle $dbh. The is useful if you need to pass the DBI handle to code that does not use SQL::Interp. $dbx->dbh()->selectall_arrayref( "SELECT * FROM mytable WHERE x = ?", undef, $x); =item C<stx> $stx = $dbx->stx(); Returns the underlying statement handle set $stx. (These are discussed later.) Each DBIx::Interp object contains one statement handle set for use on non-prepared database calls (e.g. selectall_.*() methods). $dbx->stx()->max_sths(10); =back =head2 do_i =head2 selectall_arrayref_i =head2 selectall_hashref_i =head2 selectcol_arrayref_i =head2 selectrow_array_i =head2 selectrow_arrayref_i =head2 selectrow_hashref_i These methods are identical to those in DBI except interpolation is performed via L<SQL::Interp>. =head2 prepare $stx = $dbx->prepare(); Creates a new statement handle set ($stx of type SQL::Interp::STX) associated with $dbx. There are no parameters. A statement handle set (stx) is an abstraction of a statement handle and represents an entire I<set of statement handles> for a given I<class of SQL queries>. This abstraction is used because a single interpolation list may interpolate into any number of SQL queries (depending on variable input), so multiple statement handles may need to be managed and cached. Typically, you do not need to call "prepare" directly because DBIx::Interp can transparently mangage a statement handle set (see $dbx->stx()->max_sths(10)). Up to one statement handle in a set is considered I<active>. Other operations performed on the statement handle set are passed to the active statement handle so that the statement handle set often looks and feels like a regular statement handle. =head2 Statement handle set (STX) methods These methods are for statement handle set objects. =over 4 =item C<new> $stx = SQL::Interp::STX->new($dbx); Creates a new statement handle set. Typically this is not called directly but rather is invoked through C<prepare()>. =item C<max_sths> $max_sths = $stx->max_sths(); # get $stx->max_sths($max_sths); # set Gets or sets the maximum number of statement handles to cache in the statement handle set. The default and minimum value is 1. =item C<sth> $sth = $stx->sth(); Gets the current active statement handle (e.g. the only that was just executed). Returns undef on none. =item C<sths> $sths = $stx->sths(); Return a hashref of contained statement handles (map: $sql -> $sth). =item C<execute> $rv = $stx->execute(@list); Executes the query in the given interpolation list against a statement handle. If no statement matching statement handle exists, a new one is prepared. The used statement handle is made the active statement handle. Return on error behavior is similar to DBI's execute. @list is an interpolation list (suitable for passing to C<dbi_interp()>). =item C<fetch...> $ary_ref = $stx->fetchrow_arrayref(); Various fetch.* methods analogous to those in DBIx::Interp are available. The fetch will be performed against the active statement handle in the set. =back =begin private =head1 Internal functions You normally don't need to care about this functions. =head2 C<dbi_interp> ($sql, $attr, @bind) = dbi_interp(@interp_list); ($sql, $key_field, $attr, @bind) = dbi_interp(@interp_list); C<dbi_interp()> is a thin wrapper around C<sql_interp()>. It serves as an adapter that returns the exact parameter list expected by the DBI functions (including the \%attr value and sometimes the $key_field value). In addition to the parameters accepted by SQL::Interp::sql_interp, @interp_list may contain the results constructed by the C<attr()> and C<key_field()> functions discussed later. C<dbi_interp()> will convert these DBI-specific values as needed into additional return values expected by certain DBI methods. Typically, you need not call C<dbi_interp()> directly since it is called internally by the DBI wrapper methods: $dbx->selectall_hashref( "SELECT * FROM mytable WHERE x=", \$x, key_field("y"), attr(myatt => 1)); # largely equivalent to # $dbh->selectall_hashref(dbi_interp # "SELECT * FROM mytable WHERE x=", \$x, # key_field("y"), attr(myatt => 1)); =end private These are more advanced examples. =head2 Binding variable types (DBI bind_param) Compare this much simpler code to L<the example in SQL::Interp|SQL::Interp/ADDITIONAL_EXAMPLES>. $dbx->selectall_arrayref( "SELECT * FROM mytable WHERE", "x=", \$x, "AND y=", sql_type(\$y, SQL_VARCHAR), "AND z IN", sql_type([1, 2], SQL_INTEGER) ); =head1 DESIGN NOTES =head2 Philosophy and requirements DBIx::Interp is designed to look an feel like DBI even when the DBI interface is not entirely user friendly (e.g. the (fetch|select)(all|row)?_(array|hash)(ref)? and do methods). Still, the approach lowers the learning code and could simplify the process of converting existing DBI code over to SQL::Interp. The use of statement handle sets (STX) is not strictly necessary but is rather designed to mimic DBI's statement handles more than anything else. The DBX object itself contains a statement handle set, which can be used for non-prepared calls such as to selectall_.*() methods (i.e. cache statement handles like in DBIx::Simple's keep_statements). $dbx->stx()->max_sths(2); $dbx->do(...) for 1..5; $dbx->do(...) for 1..5; An ideal solution would probably be to I<integrate SQL::Interp into DBIx::Simple> rather than directly into DBI. =head2 Proposed enhancements The following enhancements to SQL::Interp have been proposed. The most important suggestions are listed at top, and some suggestions could be rejected. DBI database handle and statement handle attributes are not currently exposed from the wrapper except via $dbx->dbh()->{...}. Maybe a Tie can be used. e.g. $dbx->{mysql_insert_id} Support might be added for something analogous to DBI's bind_param_inout. DBI's bind_param_array is not currently supported. A syntax as follows might be used: "INSERT INTO mytable", [[...], [...], ...] Passing identified variables: my $x = {one => 'two'}; my $stx = $dbx->prepare("SELECT * FROM mytable WHERE", sql_type(\$x); $stx->execute_vars(); ... $x->{two} = 'three'; $stx->execute_vars(); ... my $x = {one => 'two'}; my $y = {one => 'three', two => 'four'}; my $stx = $dbx->prepare("SELECT * FROM mytable WHERE", sql_type($x, 'x')); $stx->execute_vars(); ... $stx->execute_vars(sql_type($x, 'x'); # or? $stx->execute_vars(x => $x); # or? ... =head1 CONTRIBUTORS David Manura (L<http://math2.org/david>) (author). The existence and original design of this module as a wrapper around DBI was suggested by Jim Cromie. =head1 FEEDBACK Bug reports and comments on the design are most welcome. See the main L<SQL::Interp|SQL::Interp> module for details. =head1 LEGAL Copyright (c) 2004-2005, David Manura. This module is free software. It may be used, redistributed and/or modified under the same terms as Perl itself. See L<http://www.perl.com/perl/misc/Artistic.html>. =head1 SEE ALSO =head2 Other modules in this distribution L<SQL::Interp|SQL::Interp>, L<DBI|DBI>. Related modules: L<DBIx::Simple|DBIx::Simple>, L<SQL::Abstract|SQL::Abstract>, L<DBIx::Abstract|DBIx::Abstract>, L<Class::DBI|Class::DBI>, L<DBIx::Class|DBIx::Class>, L<Rose::DB|Rose::DB>. =cut