David Precious > HTML-Table-FromDatabase-1.10 > HTML::Table::FromDatabase

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NAME ^

HTML::Table::FromDatabase - a subclass of HTML::Table to easily generate a HTML table from the result of a database query

SYNOPSIS ^

 my $sth = $dbh->prepare('select * from my_table')
    or die "Failed to prepare query - " . $dbh->errstr;
 $sth->execute() or die "Failed to execute query - " . $dbh->errstr;

 my $table = HTML::Table::FromDatabase->new( -sth => $sth );
 $table->print;

DESCRIPTION ^

Subclasses HTML::Table, providing a quick and easy way to produce HTML tables from the result of a database query.

I often find myself writing scripts which fetch data from a database and present it in a HTML table; often resulting in pointlessly repeated code to take the results and turn them into a table.

HTML::Table itself helps here, but this module makes it even simpler.

Column headings are taken from the field names returned by the query, unless overridden with the -override_headers or -rename_headers options.

All options you pass to the constructor will be passed through to HTML::Table, so you can use all the usual HTML::Table features.

INTERFACE ^

new

Constructor method - consult HTML::Table's documentation, the only difference here is the addition of the following parameters:

-sth

(required) a DBI statement handle which has been executed and is ready to fetch data from

-callbacks

(optional) specifies callbacks/transformations which should be applied as the table is built up (see the "CALLBACKS" section below).

-html

(optional) can be escape or strip if you want HTML to be escaped (angle brackets replaced with < and >) or stripped out with HTML::Strip.

-override_headers

(optional) provide a list of names to be used as the column headings, instead of using the names of the columns returned by the SQL query. This should be an arrayref containing the heading names, and the number of heading names must match the number of columns returned by the query.

-rename_headers

(optional) provide a hashref of oldname => newname pairs to rename some or all of the column names returned by the query when generating the table headings.

-auto_pretty_headers

(optional, boolean) - automatically make column names nicer for headings, using titlecase and swapping underscores for spaces etc (e.g. first_name becomes First Name)

-pad_empty_cells

(optional, default 1) pad empty cells with an   to ensure they're rendered with borders appropriately. Many browsers "skip" empty cells, leading to missing borders around them, which many people consider broken. To stop this, by default empty cells receive a non-breaking space as their content. If you don't want this behaviour, set this option to a false value.

CALLBACKS ^

Per-cell callbacks

You can pass an arrayref of hashrefs describing callbacks to be performed as the table is built up, which can modify the data before the table is produced.

Each callback receives the value and, as of 0.04, the $row hashref (normally you will only want to look at the value, but occasionally I've found cases where the callback needs to see the rest of the row, for various reasons).

This can be very useful; one example use-case would be turning the values in a column which contains URLs into clickable links:

 my $table = HTML::Table::FromDatabase->new(
    -sth => $sth,
    -callbacks => [
        {
            column => 'url',
            transform => sub { $_ = shift; qq[<a href="$_">$_</a>]; },
        },
    ],
 );

You can match against the column name using a key named column in the hashref (as illustrated above) or against the actual value using a key named value.

You can pass a straight scalar to compare against, a regex (using qr//), or a coderef which will be executed to determine if it matches.

You pass a coderef to be called for matching cells via the transform key. You can use callback instead if you want your coderef to be called but its return value to be discarded (i.e. you don't intend to modify the value, but do something else).

Another example - displaying all numbers to two decimal points:

 my $table = HTML::Table::FromDatabase->new(
    -sth => $sth,
    -callbacks => [
        {
            value => qr/^\d+$/,
            transform => sub { return sprintf '%.2f', shift },
        },
    ],
 );

It is hoped that this facility will allow the easiness of quickly creating a table to still be retained, even when you need to do things with the data rather than just displaying it exactly as it comes out of the database.

Per-row callbacks

You can also supply callbacks which operate on an entire row at a time with the -row_callbacks option, which simply takes an arrayref of coderefs, each of which will be called in turn, will receive the row hashref as its first parameter, and can modify the row in whatever way is desired.

  my $table = HTML::Table::FromDatabase->new(
      -sth => $sth,
      -row_callbacks => [
          sub {
            my $row = shift;
            # Do things with $row here
          },
      ],
  ):

If a row callback sets the $row hashref to undef, that row will be skipped.

A more in-depth, if somewhat contrived, example:

  my $table = HTML::Table::FromDatabase->new(
      -sth => $sth,
      -row_callbacks => [
          sub {
            my $row = shift;
            if ($row->{name} eq 'Bob') {
                # Hide this row
                $row = undef;
            } elsif ($row->{name} eq 'John') {
                # John likes to be called Jean these days:
                $row->{name} = 'Jean';
            }
          },
      ],
  );

DEPENDENCIES ^

HTML::Table, obviously :)

HTML::Strip is required if you use the -html => 'strip' option.

HTML::Entities is required if you use the -html => 'encode' option.

AUTHOR ^

David Precious, <davidp@preshweb.co.uk>

Feel free to contact me if you have any comments, suggestions or bugs to report.

THANKS ^

Thanks to Ireneusz Pluta for reporting bug with -override_headers / -rename_headers option and supplying patch in RT ticket #50164.

COPYRIGHT AND LICENSE ^

Copyright (C) 2008-2011 by David Precious

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.7 or, at your option, any later version of Perl 5 you may have available.

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