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   1  package DBI::DBD::Metadata;
   2  
   3  # $Id: Metadata.pm 8696 2007-01-24 23:12:38Z timbo $
   4  #
   5  # Copyright (c) 1997-2003 Jonathan Leffler, Jochen Wiedmann,
   6  # Steffen Goeldner and Tim Bunce
   7  #
   8  # You may distribute under the terms of either the GNU General Public
   9  # License or the Artistic License, as specified in the Perl README file.
  10  
  11  use Exporter ();
  12  use Carp;
  13  
  14  use DBI;
  15  use DBI::Const::GetInfoType qw(%GetInfoType);
  16  
  17  # Perl 5.005_03 does not recognize 'our'
  18  @ISA = qw(Exporter);
  19  @EXPORT = qw(write_getinfo_pm write_typeinfo_pm);
  20  
  21  $VERSION = sprintf("2.%06d", q$Revision: 8696 $ =~ /(\d+)/o);
  22  
  23  
  24  use strict;
  25  
  26  =head1 NAME
  27  
  28  DBI::DBD::Metadata - Generate the code and data for some DBI metadata methods
  29  
  30  =head1 SYNOPSIS
  31  
  32  The idea is to extract metadata information from a good quality
  33  ODBC driver and use it to generate code and data to use in your own
  34  DBI driver for the same database.
  35  
  36  For generating code to support the get_info method:
  37  
  38    perl -MDBI::DBD::Metadata -e "write_getinfo_pm('dbi:ODBC:dsn-name','user','pass','Driver')"
  39  
  40    perl -MDBI::DBD::Metadata -e write_getinfo_pm dbi:ODBC:foo_db username password Driver
  41  
  42  For generating code to support the type_info method:
  43  
  44    perl -MDBI::DBD::Metadata -e "write_typeinfo_pm('dbi:ODBC:dsn-name','user','pass','Driver')"
  45  
  46    perl -MDBI::DBD::Metadata -e write_typeinfo_pm dbi:ODBC:dsn-name user pass Driver
  47  
  48  Where C<dbi:ODBC:dsn-name> is the connection to use to extract the
  49  data, and C<Driver> is the name of the driver you want the code
  50  generated for (the driver name gets embedded into the output in
  51  many places).
  52  
  53  =head1 Generating a GetInfo package for a driver
  54  
  55  The C<write_getinfo_pm> in the DBI::DBD::Metadata module generates a
  56  DBD::Driver::GetInfo package on standard output.
  57  
  58  This method generates a DBD::Driver::GetInfo package from the data
  59  source you specified in the parameter list or in the environment
  60  variable DBI_DSN.
  61  DBD::Driver::GetInfo should help a DBD author implementing the DBI
  62  get_info() method.
  63  Because you are just creating this package, it's very unlikely that
  64  DBD::Driver already provides a good implementation for get_info().
  65  Thus you will probably connect via DBD::ODBC.
  66  
  67  Once you are sure that it is producing semi-sane data, you would
  68  typically redirect the standard output to lib/DBD/Driver/GetInfo.pm, and
  69  then hand edit the result.
  70  Do not forget to update your Makefile.PL and MANIFEST to include this as
  71  an extra PM file that should be installed.
  72  
  73  If you connect via DBD::ODBC, you should use version 0.38 or greater;
  74  
  75  Please take a critical look at the data returned!
  76  ODBC drivers vary dramatically in their quality.
  77  
  78  The generator assumes that most values are static and places these
  79  values directly in the %info hash.
  80  A few examples show the use of CODE references and the implementation
  81  via subroutines.
  82  It is very likely that you have to write additional subroutines for
  83  values depending on the session state or server version, e.g.
  84  SQL_DBMS_VER.
  85  
  86  A possible implementation of DBD::Driver::db::get_info() may look like:
  87  
  88    sub get_info {
  89      my($dbh, $info_type) = @_;
  90      require DBD::Driver::GetInfo;
  91      my $v = $DBD::Driver::GetInfo::info{int($info_type)};
  92      $v = $v->($dbh) if ref $v eq 'CODE';
  93      return $v;
  94    }
  95  
  96  Please replace Driver (or "<foo>") with the name of your driver.
  97  Note that this stub function is generated for you by write_getinfo_pm
  98  function, but you must manually transfer the code to Driver.pm.
  99  
 100  =cut
 101  
 102  sub write_getinfo_pm
 103  {
 104      my ($dsn, $user, $pass, $driver) = @_ ? @_ : @ARGV;
 105      my $dbh = DBI->connect($dsn, $user, $pass, {RaiseError=>1});
 106      $driver = "<foo>" unless defined $driver;
 107  
 108      print <<PERL;
 109  
 110  # Transfer this to ${driver}.pm
 111  
 112  # The get_info function was automatically generated by
 113  # DBI::DBD::Metadata::write_getinfo_pm v$DBI::DBD::Metadata::VERSION.
 114  
 115  package DBD::$driver}::db;         # This line can be removed once transferred.
 116  
 117      sub get_info {
 118          my(\$dbh, \$info_type) = \@_;
 119          require DBD::$driver}::GetInfo;
 120          my \$v = \$DBD::$driver}::GetInfo::info{int(\$info_type)};
 121          \$v = \$v->(\$dbh) if ref \$v eq 'CODE';
 122          return \$v;
 123      }
 124  
 125  # Transfer this to lib/DBD/${driver}/GetInfo.pm
 126  
 127  # The \%info hash was automatically generated by
 128  # DBI::DBD::Metadata::write_getinfo_pm v$DBI::DBD::Metadata::VERSION.
 129  
 130  package DBD::$driver}::GetInfo;
 131  
 132  use strict;
 133  use DBD::$driver};
 134  
 135  # Beware: not officially documented interfaces...
 136  # use DBI::Const::GetInfoType qw(\%GetInfoType);
 137  # use DBI::Const::GetInfoReturn qw(\%GetInfoReturnTypes \%GetInfoReturnValues);
 138  
 139  my \$sql_driver = '$driver}';
 140  my \$sql_ver_fmt = '%02d.%02d.%04d';   # ODBC version string: ##.##.#####
 141  my \$sql_driver_ver = sprintf \$sql_ver_fmt, split (/\\./, \$DBD::$driver}::VERSION);
 142  PERL
 143  
 144  my $kw_map = 0;
 145  {
 146  # Informix CLI (ODBC) v3.81.0000 does not return a list of keywords.
 147      local $\ = "\n";
 148      local $, = "\n";
 149      my ($kw) = $dbh->get_info($GetInfoType{SQL_KEYWORDS});
 150      if ($kw)
 151      {
 152          print "\nmy \@Keywords = qw(\n";
 153          print sort split /,/, $kw;
 154          print ");\n\n";
 155          print "sub sql_keywords {\n";
 156          print q%    return join ',', @Keywords;%;
 157          print "\n}\n\n";
 158          $kw_map = 1;
 159      }
 160  }
 161  
 162      print <<'PERL';
 163  
 164  sub sql_data_source_name {
 165      my $dbh = shift;
 166      return "dbi:$sql_driver:" . $dbh->{Name};
 167  }
 168  
 169  sub sql_user_name {
 170      my $dbh = shift;
 171      # CURRENT_USER is a non-standard attribute, probably undef
 172      # Username is a standard DBI attribute
 173      return $dbh->{CURRENT_USER} || $dbh->{Username};
 174  }
 175  
 176  PERL
 177  
 178      print "\nour \%info = (\n";
 179      foreach my $key (sort keys %GetInfoType)
 180      {
 181          my $num = $GetInfoType{$key};
 182          my $val = eval { $dbh->get_info($num); };
 183          if ($key eq 'SQL_DATA_SOURCE_NAME') {
 184              $val = '\&sql_data_source_name';
 185          }
 186          elsif ($key eq 'SQL_KEYWORDS') {
 187              $val = ($kw_map) ? '\&sql_keywords' : 'undef';
 188          }
 189          elsif ($key eq 'SQL_DRIVER_NAME') {
 190              $val = "\$INC{'DBD/$driver.pm'}";
 191          }
 192          elsif ($key eq 'SQL_DRIVER_VER') {
 193              $val = '$sql_driver_ver';
 194          }
 195          elsif ($key eq 'SQL_USER_NAME') {
 196              $val = '\&sql_user_name';
 197          }
 198          elsif (not defined $val) {
 199              $val = 'undef';
 200          }
 201          elsif ($val eq '') {
 202              $val = "''";
 203          }
 204          elsif ($val =~ /\D/) {
 205              $val =~ s/\\/\\\\/g;
 206              $val =~ s/'/\\'/g;
 207              $val = "'$val'";
 208          }
 209          printf "%s %5d => %-30s # %s\n", (($val eq 'undef') ? '#' : ' '), $num, "$val,", $key;
 210      }
 211      print ");\n\n1;\n\n__END__\n";
 212  }
 213  
 214  
 215  
 216  =head1 Generating a TypeInfo package for a driver
 217  
 218  The C<write_typeinfo_pm> function in the DBI::DBD::Metadata module generates
 219  on standard output the data needed for a driver's type_info_all method.
 220  It also provides default implementations of the type_info_all
 221  method for inclusion in the driver's main implementation file.
 222  
 223  The driver parameter is the name of the driver for which the methods
 224  will be generated; for the sake of examples, this will be "Driver".
 225  Typically, the dsn parameter will be of the form "dbi:ODBC:odbc_dsn",
 226  where the odbc_dsn is a DSN for one of the driver's databases.
 227  The user and pass parameters are the other optional connection
 228  parameters that will be provided to the DBI connect method.
 229  
 230  Once you are sure that it is producing semi-sane data, you would
 231  typically redirect the standard output to lib/DBD/Driver/TypeInfo.pm,
 232  and then hand edit the result if necessary.
 233  Do not forget to update your Makefile.PL and MANIFEST to include this as
 234  an extra PM file that should be installed.
 235  
 236  Please take a critical look at the data returned!
 237  ODBC drivers vary dramatically in their quality.
 238  
 239  The generator assumes that all the values are static and places these
 240  values directly in the %info hash.
 241  
 242  A possible implementation of DBD::Driver::type_info_all() may look like:
 243  
 244    sub type_info_all {
 245      my ($dbh) = @_;
 246      require DBD::Driver::TypeInfo;
 247      return [ @$DBD::Driver::TypeInfo::type_info_all ];
 248    }
 249  
 250  Please replace Driver (or "<foo>") with the name of your driver.
 251  Note that this stub function is generated for you by the write_typeinfo_pm
 252  function, but you must manually transfer the code to Driver.pm.
 253  
 254  =cut
 255  
 256  
 257  # These two are used by fmt_value...
 258  my %dbi_inv;
 259  my %sql_type_inv;
 260  
 261  #-DEBUGGING-#
 262  #sub print_hash
 263  #{
 264  #   my ($name, %hash) = @_;
 265  #   print "Hash: $name\n";
 266  #   foreach my $key (keys %hash)
 267  #   {
 268  #       print "$key => $hash{$key}\n";
 269  #   }
 270  #}
 271  #-DEBUGGING-#
 272  
 273  sub inverse_hash
 274  {
 275      my (%hash) = @_;
 276      my (%inv);
 277      foreach my $key (keys %hash)
 278      {
 279          my $val = $hash{$key};
 280          die "Double mapping for key value $val ($inv{$val}, $key)!"
 281              if (defined $inv{$val});
 282          $inv{$val} = $key;
 283      }
 284      return %inv;
 285  }
 286  
 287  sub fmt_value
 288  {
 289      my ($num, $val) = @_;
 290      if (!defined $val)
 291      {
 292          $val = "undef";
 293      }
 294      elsif ($val !~ m/^[-+]?\d+$/)
 295      {
 296          # All the numbers in type_info_all are integers!
 297          # Anything that isn't an integer is a string.
 298          # Ensure that no double quotes screw things up.
 299          $val =~ s/"/\\"/g if ($val =~ m/"/o);
 300          $val = qq{"$val"};
 301      }
 302      elsif ($dbi_inv{$num} =~ m/^(SQL_)?DATA_TYPE$/)
 303      {
 304          # All numeric...
 305          $val = $sql_type_inv{$val}
 306              if (defined $sql_type_inv{$val});
 307      }
 308      return $val;
 309  }
 310  
 311  sub write_typeinfo_pm
 312  {
 313      my ($dsn, $user, $pass, $driver) = @_ ? @_ : @ARGV;
 314      my $dbh = DBI->connect($dsn, $user, $pass, {AutoCommit=>1, RaiseError=>1});
 315      $driver = "<foo>" unless defined $driver;
 316  
 317      print <<PERL;
 318  
 319  # Transfer this to ${driver}.pm
 320  
 321  # The type_info_all function was automatically generated by
 322  # DBI::DBD::Metadata::write_typeinfo_pm v$DBI::DBD::Metadata::VERSION.
 323  
 324  package DBD::$driver}::db;         # This line can be removed once transferred.
 325  
 326      sub type_info_all
 327      {
 328          my (\$dbh) = \@_;
 329          require DBD::$driver}::TypeInfo;
 330          return [ \@\$DBD::$driver}::TypeInfo::type_info_all ];
 331      }
 332  
 333  # Transfer this to lib/DBD/${driver}/TypeInfo.pm.
 334  # Don't forget to add version and intellectual property control information.
 335  
 336  # The \%type_info_all hash was automatically generated by
 337  # DBI::DBD::Metadata::write_typeinfo_pm v$DBI::DBD::Metadata::VERSION.
 338  
 339  package DBD::$driver}::TypeInfo;
 340  
 341  {
 342      require Exporter;
 343      require DynaLoader;
 344      \@ISA = qw(Exporter DynaLoader);
 345      \@EXPORT = qw(type_info_all);
 346      use DBI qw(:sql_types);
 347  
 348  PERL
 349  
 350      # Generate SQL type name mapping hashes.
 351      # See code fragment in DBI specification.
 352      my %sql_type_map;
 353      foreach (@{$DBI::EXPORT_TAGS{sql_types}})
 354      {
 355          no strict 'refs';
 356          $sql_type_map{$_} = &{"DBI::$_"}();
 357          $sql_type_inv{$sql_type_map{$_}} = $_;
 358      }
 359      #-DEBUG-# print_hash("sql_type_map", %sql_type_map);
 360      #-DEBUG-# print_hash("sql_type_inv", %sql_type_inv);
 361  
 362      my %dbi_map =
 363          (
 364              TYPE_NAME          =>  0,
 365              DATA_TYPE          =>  1,
 366              COLUMN_SIZE        =>  2,
 367              LITERAL_PREFIX     =>  3,
 368              LITERAL_SUFFIX     =>  4,
 369              CREATE_PARAMS      =>  5,
 370              NULLABLE           =>  6,
 371              CASE_SENSITIVE     =>  7,
 372              SEARCHABLE         =>  8,
 373              UNSIGNED_ATTRIBUTE =>  9,
 374              FIXED_PREC_SCALE   => 10,
 375              AUTO_UNIQUE_VALUE  => 11,
 376              LOCAL_TYPE_NAME    => 12,
 377              MINIMUM_SCALE      => 13,
 378              MAXIMUM_SCALE      => 14,
 379              SQL_DATA_TYPE      => 15,
 380              SQL_DATETIME_SUB   => 16,
 381              NUM_PREC_RADIX     => 17,
 382              INTERVAL_PRECISION => 18,
 383          );
 384  
 385      #-DEBUG-# print_hash("dbi_map", %dbi_map);
 386  
 387      %dbi_inv = inverse_hash(%dbi_map);
 388  
 389      #-DEBUG-# print_hash("dbi_inv", %dbi_inv);
 390  
 391      my $maxlen = 0;
 392      foreach my $key (keys %dbi_map)
 393      {
 394          $maxlen = length($key) if length($key) > $maxlen;
 395      }
 396  
 397      # Print the name/value mapping entry in the type_info_all array;
 398      my $fmt = "            \%-$maxlen}s => \%2d,\n";
 399      my $numkey = 0;
 400      my $maxkey = 0;
 401      print "    \$type_info_all = [\n        {\n";
 402      foreach my $i (sort { $a <=> $b } keys %dbi_inv)
 403      {
 404          printf($fmt, $dbi_inv{$i}, $i);
 405          $numkey++;
 406          $maxkey = $i;
 407      }
 408      print "        },\n";
 409  
 410      print STDERR "### WARNING - Non-dense set of keys ($numkey keys, $maxkey max key)\n"
 411          unless $numkey = $maxkey + 1;
 412  
 413      my $h = $dbh->type_info_all;
 414      my @tia = @$h;
 415      my %odbc_map = map { uc $_ => $tia[0]->{$_} } keys %{$tia[0]};
 416      shift @tia;     # Remove the mapping reference.
 417      my $numtyp = $#tia;
 418  
 419      #-DEBUG-# print_hash("odbc_map", %odbc_map);
 420  
 421      # In theory, the key/number mapping sequence for %dbi_map
 422      # should be the same as the one from the ODBC driver.  However, to
 423      # prevent the possibility of mismatches, and to deal with older
 424      # missing attributes or unexpected new ones, we chase back through
 425      # the %dbi_inv and %odbc_map hashes, generating @dbi_to_odbc
 426      # to map our new key number to the old one.
 427      # Report if @dbi_to_odbc is not an identity mapping.
 428      my @dbi_to_odbc;
 429      foreach my $num (sort { $a <=> $b } keys %dbi_inv)
 430      {
 431          # Find the name in %dbi_inv that matches this index number.
 432          my $dbi_key = $dbi_inv{$num};
 433          #-DEBUG-# print "dbi_key = $dbi_key\n";
 434          #-DEBUG-# print "odbc_key = $odbc_map{$dbi_key}\n";
 435          # Find the index in %odbc_map that has this key.
 436          $dbi_to_odbc[$num] = (defined $odbc_map{$dbi_key}) ? $odbc_map{$dbi_key} : undef;
 437      }
 438  
 439      # Determine the length of the longest formatted value in each field
 440      my @len;
 441      for (my $i = 0; $i <= $numtyp; $i++)
 442      {
 443          my @odbc_val = @{$tia[$i]};
 444          for (my $num = 0; $num <= $maxkey; $num++)
 445          {
 446              # Find the value of the entry in the @odbc_val array.
 447              my $val = (defined $dbi_to_odbc[$num]) ? $odbc_val[$dbi_to_odbc[$num]] : undef;
 448              $val = fmt_value($num, $val);
 449              #-DEBUG-# print "val = $val\n";
 450              $val = "$val,";
 451              $len[$num] = length($val) if !defined $len[$num] || length($val) > $len[$num];
 452          }
 453      }
 454  
 455      # Generate format strings to left justify each string in maximum field width.
 456      my @fmt;
 457      for (my $i = 0; $i <= $maxkey; $i++)
 458      {
 459          $fmt[$i] = "%-$len[$i]s";
 460          #-DEBUG-# print "fmt[$i] = $fmt[$i]\n";
 461      }
 462  
 463      # Format the data from type_info_all
 464      for (my $i = 0; $i <= $numtyp; $i++)
 465      {
 466          my @odbc_val = @{$tia[$i]};
 467          print "        [ ";
 468          for (my $num = 0; $num <= $maxkey; $num++)
 469          {
 470              # Find the value of the entry in the @odbc_val array.
 471              my $val = (defined $dbi_to_odbc[$num]) ? $odbc_val[$dbi_to_odbc[$num]] : undef;
 472              $val = fmt_value($num, $val);
 473              printf $fmt[$num], "$val,";
 474          }
 475          print " ],\n";
 476      }
 477  
 478      print "    ];\n\n    1;\n}\n\n__END__\n";
 479  
 480  }
 481  
 482  1;
 483  
 484  __END__
 485  
 486  =head1 AUTHORS
 487  
 488  Jonathan Leffler <jleffler@us.ibm.com> (previously <jleffler@informix.com>),
 489  Jochen Wiedmann <joe@ispsoft.de>,
 490  Steffen Goeldner <sgoeldner@cpan.org>,
 491  and Tim Bunce <dbi-users@perl.org>.
 492  
 493  =cut