Current File : //usr/share/perl5/vendor_perl/DBIx/Simple/Examples.pod
=head1 NAME
DBIx::Simple::Examples - Examples of how to use DBIx::Simple
=head1 DESCRIPTION
DBIx::Simple provides a simplified interface to DBI, Perl's powerful database
module.
=head1 EXAMPLES
=head2 General
#!/usr/bin/perl -w
use strict;
use DBIx::Simple;
# Instant database with DBD::SQLite
my $db = DBIx::Simple->connect('dbi:SQLite:dbname=file.dat')
or die DBIx::Simple->error;
# Connecting to a MySQL database
my $db = DBIx::Simple->connect(
'DBI:mysql:database=test', # DBI source specification
'test', 'test', # Username and password
{ RaiseError => 1 } # Additional options
);
# Using an existing database handle
my $db = DBIx::Simple->connect($dbh);
# Abstracted example: $db->query($query, @variables)->what_you_want;
$db->commit or die $db->error;
=head2 Simple Queries
$db->query('DELETE FROM foo WHERE id = ?', $id) or die $db->error;
for (1..100) {
$db->query(
'INSERT INTO randomvalues VALUES (?, ?)',
int rand(10),
int rand(10)
) or die $db->error;
}
$db->query(
'INSERT INTO sometable VALUES (??)',
$first, $second, $third, $fourth, $fifth, $sixth
);
# (??) is expanded to (?, ?, ?, ?, ?, ?) automatically
=head2 Single row queries
my ($two) = $db->query('SELECT 1 + 1')->list;
my ($three, $four) = $db->query('SELECT 3, 2 + 2')->list;
my ($name, $email) = $db->query(
'SELECT name, email FROM people WHERE email = ? LIMIT 1',
$mail
)->list;
Or, more efficiently:
$db->query('SELECT 1 + 1')->into(my $two);
$db->query('SELECT 3, 2 + 2')->into(my ($three, $four));
$db->query(
'SELECT name, email FROM people WHERE email = ? LIMIT 1',
$mail
)->into(my ($name, $email));
=head2 Fetching all rows in one go
=head3 One big flattened list (primarily for single column queries)
my @names = $db->query('SELECT name FROM people WHERE id > 5')->flat;
=head3 Rows as array references
for my $row ($db->query('SELECT name, email FROM people')->arrays) {
print "Name: $row->[0], Email: $row->[1]\n";
}
=head3 Rows as hash references
for my $row ($db->query('SELECT name, email FROM people')->hashes) {
print "Name: $row->{name}, Email: $row->{email}\n";
}
=head2 Fetching one row at a time
=head3 Rows into separate variables
{
my $result = $db->query('SELECT name, email FROM people');
$result->bind(my ($name, $email));
while ($result->fetch) {
print "Name: $name, Email: $email\n";
}
}
or:
{
my $result = $db->query('SELECT name, email FROM people');
while ($result->into(my ($name, $email))) {
print "Name: $name, Email: $email\n";
}
}
=head3 Rows as lists
{
my $result = $db->query('SELECT name, email FROM people');
while (my @row = $result->list) {
print "Name: $row[0], Email: $row[1]\n";
}
}
=head3 Rows as array references
{
my $result = $db->query('SELECT name, email FROM people');
while (my $row = $result->array) {
print "Name: $row->[0], Email: $row->[1]\n";
}
}
=head3 Rows as hash references
{
my $result = $db->query('SELECT name, email FROM people');
while (my $row = $result->hash) {
print "Name: $row->{name}, Email: $row->{email}\n";
}
}
=head2 Building maps (also fetching all rows in one go)
=head3 A hash of hashes
my $customers =
$db
-> query('SELECT id, name, location FROM people')
-> map_hashes('id');
# $customers = { $id => { name => $name, location => $location } }
=head3 A hash of arrays
my $customers =
$db
-> query('SELECT id, name, location FROM people')
-> map_arrays(0);
# $customers = { $id => [ $name, $location ] }
=head3 A hash of values (two-column queries)
my $names =
$db
-> query('SELECT id, name FROM people')
-> map;
# $names = { $id => $name }
=head1 EXAMPLES WITH SQL::Interp
If you have SQL::Interp installed, you can use the semi-abstracting method
C<iquery>. This works just like C<query>, but with parts of the query
interleaved with the bind arguments, passed as references.
You should read L<SQL::Interp>. These examples are not enough to fully
understand all the possibilities.
The following examples are based on the documentation of SQL::Interp.
my $result = $db->iquery('INSERT INTO table', \%item);
my $result = $db->iquery('UPDATE table SET', \%item, 'WHERE y <> ', \2);
my $result = $db->iquery('DELETE FROM table WHERE y = ', \2);
# These two select syntax produce the same result
my $result = $db->iquery('SELECT * FROM table WHERE x = ', \$s, 'AND y IN', \@v);
my $result = $db->iquery('SELECT * FROM table WHERE', {x => $s, y => \@v});
for ($result->hashes) { ... }
Use a syntax highlighting editor for good visual distinction.
If you need the helper functions C<sql> and C<sql_type>, you can import them
with C<use SQL::Interp;>
=head1 EXAMPLES WITH SQL::Abstract
If you have SQL::Abstract installed, you can use the abstracting methods
C<select>, C<insert>, C<update>, C<delete>. These work like C<query>, but
instead of a query and bind arguments, use abstracted arguments.
You should read L<SQL::Abstract>. These examples are not enough to fully
understand all the possibilities.
The SQL::Abstract object is available (writable) through the C<abstract>
property.
The following examples are based on the documentation of SQL::Abstract.
=head2 Overview
If you don't like the defaults, just assign a new object:
$db->abstract = SQL::Abstract->new(
case => 'lower',
cmp => 'like',
logic => 'and',
convert => 'upper'
);
If you don't assign any object, one will be created automatically using the
default options. The SQL::Abstract module is loaded on demand.
my $result = $db->select($table, \@fields, \%where, \@order);
my $result = $db->insert($table, \%fieldvals || \@values);
my $result = $db->update($table, \%fieldvals, \%where);
my $result = $db->delete($table, \%where);
for ($result->hashes) { ... }
=head2 Complete examples
=head3 select
my @tickets = $db->select(
'tickets', '*', {
requestor => 'inna',
worker => ['nwiger', 'rcwe', 'sfz'],
status => { '!=', 'completed' }
}
)->hashes;
=head3 insert
If you already have your data as a hash, inserting becomes much easier:
$db->insert('people', \%data);
Instead of:
$db->query(
q[
INSERT
INTO people (name, phone, address, ...)
VALUES (??)
],
@data{'name', 'phone', 'address', ... }
);
=head3 update, delete
$db->update(
'tickets', {
worker => 'juerd',
status => 'completed'
},
{ id => $id }
)
$db->delete('tickets', { id => $id });
=head3 where
The C<where> method is not wrapped directly, because it doesn't generate a
query and thus doesn't really have anything to do with the database module.
But using the C<abstract> property, you can still easily access it:
my $where = $db->abstract->where({ foo => $foo });
=head1 EXAMPLES WITH DBIx::XHTML_Table
If you have DBIx::XHTML_Table installed, you can use the result methods
C<xto> and C<html>.
You should read L<DBIx::XHTML_Table>. These examples are not enough to fully
understand what is going on. When reading that documentation, note that you
don't have to pass hash references to DBIx::Simple's methods. It is supported,
though.
DBIx::XHTML_Table is loaded on demand.
=head2 Overview
To print a simple table, all you have to do is:
print $db->query('SELECT * FROM foo')->html;
Of course, anything that produces a result object can be used. The same thing
using the abstraction method C<select> would be:
print $db->select('foo', '*')->html;
A DBIx::XHTML_Table object can be generated with the C<xto> (B<X>HTML_B<T>able
B<O>bject) method:
my $table = $db->query($query)->xto;
=head2 Passing attributes
DBIx::Simple sends the attributes you pass to C<html> both to the constructor
and the output method. This allows you to specify both HTML attributes (like
C<bgcolor>) and options for XHTML_Table (like C<no_ucfirst> and C<no_indent>)
all at once:
print $result->html(
tr => { bgcolor => [ qw/silver white/ ] },
no_ucfirst => 1
);
=head2 Using an XHTML_Table object
Not everything can be controlled by passing attributes. For full flexibility,
the XHTML_Table object can be used directly:
my $table = $db->query($query)->xto(
tr => { bgcolor => [ qw/silver white/ ] }
);
$table->set_group('client', 1);
$table->calc_totals('credit', '%.2f');
print $table->output({ no_ucfirst => 1 }); # note the {}!
=head1 EXAMPLES WITH Text::Table
=over 8
=item C<< $result->text("neat") >>
Neither neat nor pretty, but useful for debugging. Uses DBI's C<neat_list>
method. Doesn't display column names.
'1', 'Camel', 'mammal'
'2', 'Llama', 'mammal'
'3', 'Owl', 'bird'
'4', 'Juerd', undef
=item C<< $result->text("table") >>
Displays a simple table using ASCII lines.
id | animal | type
---+--------+-------
1 | Camel | mammal
2 | Llama | mammal
3 | Owl | bird
4 | Juerd |
=item C<< $result->text("box") >>
Displays a simple table using ASCII lines, with an outside border.
+----+--------+--------+
| id | animal | type |
+----+--------+--------+
| 1 | Camel | mammal |
| 2 | Llama | mammal |
| 3 | Owl | bird |
| 4 | Juerd | |
+----+--------+--------+
=back
For C<table> and C<box>, you need Anno Siegel's Text::Table module installed.
=head1 AUTHOR
Juerd Waalboer <juerd@cpan.org> <http://juerd.nl/>
=head1 SEE ALSO
L<DBIx::Simple>, L<SQL::Abstract>
=cut
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