1DBIx::Class::ResultSet:U:sPeargeCro(n3t)ributed Perl DocDuBmIexn:t:aCtliaosns::ResultSet::Pager(3)
2
6 DBIx::Class::ResultSet::Pager - help when paging through sets of
7 results
8
10 use DBIx::Class::ResultSet::Pager;
11 my $page = DBIx::Class::ResultSet::Pager->new();
13 $page->total_entries($total_entries);
14 $page->entries_per_page($entries_per_page);
15 $page->current_page($current_page);
16 print " First page: ", $page->first_page, "\n";
18 print " Last page: ", $page->last_page, "\n";
19 print "First entry on page: ", $page->first, "\n";
20 print " Last entry on page: ", $page->last, "\n";
21
23 This module is a near-verbatim copy of Data::Page 2.02
24 <https://metacpan.org/pod/release/LBROCARD/Data-
25 Page-2.02/lib/Data/Page.pm>, which remained unchanged on CPAN from late
26 2009 through late 2019. The only differences are dropping a number of
27 accessor generators in lieu of direct method implementations, and the
28 incorporation of the lazily evaluated "total_entries" which was the
29 only part originally provided by DBIx::Class::ResultSet::Pager. This
30 module passes the entire contemporary test suite of Data::Page
31 unmodified.
32 WHAT FOLLOWS IS A VERBATIM COPY OF Data::Page's 2.02 DOCUMENTATION
34 When searching through large amounts of data, it is often the case that
36 a result set is returned that is larger than we want to display on one
37 page. This results in wanting to page through various pages of data.
38 The maths behind this is unfortunately fiddly, hence this module.
39 The main concept is that you pass in the number of total entries, the
41 number of entries per page, and the current page number. You can then
42 call methods to find out how many pages of information there are, and
43 what number the first and last entries on the current page really are.
44 For example, say we wished to page through the integers from 1 to 100
46 with 20 entries per page. The first page would consist of 1-20, the
47 second page from 21-40, the third page from 41-60, the fourth page from
48 61-80 and the fifth page from 81-100. This module would help you work
49 this out.
50
52 new
53 This is the constructor, which takes no arguments.
54 my $page = DBIx::Class::ResultSet::Pager->new();
56 There is also an old, deprecated constructor, which currently takes two
58 mandatory arguments, the total number of entries and the number of
59 entries per page. It also optionally takes the current page number:
60 my $page = DBIx::Class::ResultSet::Pager->new($total_entries, $entries_per_page, $current_page);
62 total_entries
64 This method get or sets the total number of entries:
65 print "Entries:", $page->total_entries, "\n";
67 entries_per_page
69 This method gets or sets the total number of entries per page (which
70 defaults to 10):
71 print "Per page:", $page->entries_per_page, "\n";
73 current_page
75 This method gets or sets the current page number (which defaults to 1):
76 print "Page: ", $page->current_page, "\n";
78 entries_on_this_page
80 This methods returns the number of entries on the current page:
81 print "There are ", $page->entries_on_this_page, " entries displayed\n";
83 first_page
85 This method returns the first page. This is put in for reasons of
86 symmetry with last_page, as it always returns 1:
87 print "Pages range from: ", $page->first_page, "\n";
89 last_page
91 This method returns the total number of pages of information:
92 print "Pages range to: ", $page->last_page, "\n";
94 first
96 This method returns the number of the first entry on the current page:
97 print "Showing entries from: ", $page->first, "\n";
99 last
101 This method returns the number of the last entry on the current page:
102 print "Showing entries to: ", $page->last, "\n";
104 previous_page
106 This method returns the previous page number, if one exists. Otherwise
107 it returns undefined:
108 if ($page->previous_page) {
110 print "Previous page number: ", $page->previous_page, "\n";
111 }
112 next_page
114 This method returns the next page number, if one exists. Otherwise it
115 returns undefined:
116 if ($page->next_page) {
118 print "Next page number: ", $page->next_page, "\n";
119 }
120 splice
122 This method takes in a listref, and returns only the values which are
123 on the current page:
124 @visible_holidays = $page->splice(\@holidays);
126 skipped
128 This method is useful paging through data in a database using SQL LIMIT
129 clauses. It is simply $page->first - 1:
130 $sth = $dbh->prepare(
132 q{SELECT * FROM table ORDER BY rec_date LIMIT ?, ?}
133 );
134 $sth->execute($page->skipped, $page->entries_per_page);
135 change_entries_per_page
137 This method changes the number of entries per page and the current page
138 number such that the first item on the current page will be present on
139 the new page.
140 $page->total_entries(50);
142 $page->entries_per_page(20);
143 $page->current_page(3);
144 print $page->first; # 41
145 $page->change_entries_per_page(30);
146 print $page->current_page; # 2 - the page that item 41 will show in
147
149 It has been said before that this code is "too simple" for CPAN, but I
150 must disagree. I have seen people write this kind of code over and over
151 again and they always get it wrong. Perhaps now they will spend more
152 time getting the rest of their code right...
153 Based on code originally by Leo Lapworth, with many changes added by by
155 Leon Brocard <acme@astray.com>, and few enhancements by James Laver
156 (ELPENGUIN)
157
159 Check the list of additional DBIC resources.
160
162 This module is free software copyright by the DBIx::Class (DBIC)
163 authors. You can redistribute it and/or modify it under the same terms
164 as the DBIx::Class library.
165perl v5.34.0 2021-07-22 DBIx::Class::ResultSet::Pager(3)