DBIx::Simple::Examples(3) | User Contributed Perl Documentation | DBIx::Simple::Examples(3) |
NAME¶
DBIx::Simple::Examples - Examples of how to use DBIx::Simple
DESCRIPTION¶
DBIx::Simple provides a simplified interface to DBI, Perl's powerful database module.
EXAMPLES¶
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;
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, $sixth ); # (??) is expanded to (?, ?, ?, ?, ?, ?) automatically
Single row queries¶
my ($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));
Fetching all rows in one go¶
One big flattened list (primarily for single column queries)
my @names = $db->query('SELECT name FROM people WHERE id > 5')->flat;
Rows as array references
for my $row ($db->query('SELECT name, email FROM people')->arrays) { print "Name: $row->[0], Email: $row->[1]\n"; }
Rows as hash references
for my $row ($db->query('SELECT name, email FROM people')->hashes) { print "Name: $row->{name}, Email: $row->{email}\n"; }
Fetching one row at a time¶
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"; } }
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"; } }
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"; } }
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"; } }
Building maps (also fetching all rows in one go)¶
A hash of hashes
my $customers = $db -> query('SELECT id, name, location FROM people') -> map_hashes('id'); # $customers = { $id => { name => $name, location => $location } }
A hash of arrays
my $customers = $db -> query('SELECT id, name, location FROM people') -> map_arrays(0); # $customers = { $id => [ $name, $location ] }
A hash of values (two-column queries)
my $names = $db -> query('SELECT id, name FROM people') -> map; # $names = { $id => $name }
EXAMPLES WITH SQL::Interp¶
If you have SQL::Interp installed, you can use the semi-abstracting method "iquery". This works just like "query", but with parts of the query interleaved with the bind arguments, passed as references.
You should read 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 "sql" and "sql_type", you can import them with "use SQL::Interp;"
EXAMPLES WITH SQL::Abstract¶
If you have SQL::Abstract installed, you can use the abstracting methods "select", "insert", "update", "delete". These work like "query", but instead of a query and bind arguments, use abstracted arguments.
You should read SQL::Abstract. These examples are not enough to fully understand all the possibilities.
The SQL::Abstract object is available (writable) through the "abstract" property.
The following examples are based on the documentation of SQL::Abstract.
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) { ... }
Complete examples¶
select
my @tickets = $db->select( 'tickets', '*', { requestor => 'inna', worker => ['nwiger', 'rcwe', 'sfz'], status => { '!=', 'completed' } } )->hashes;
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', ... } );
update, delete
$db->update( 'tickets', { worker => 'juerd', status => 'completed' }, { id => $id } ) $db->delete('tickets', { id => $id });
where
The "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 "abstract" property, you can still easily access it:
my $where = $db->abstract->where({ foo => $foo });
EXAMPLES WITH DBIx::XHTML_Table¶
If you have DBIx::XHTML_Table installed, you can use the result methods "xto" and "html".
You should read 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.
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 "select" would be:
print $db->select('foo', '*')->html;
A DBIx::XHTML_Table object can be generated with the "xto" (XHTML_Table Object) method:
my $table = $db->query($query)->xto;
Passing attributes¶
DBIx::Simple sends the attributes you pass to "html" both to the constructor and the output method. This allows you to specify both HTML attributes (like "bgcolor") and options for XHTML_Table (like "no_ucfirst" and "no_indent") all at once:
print $result->html( tr => { bgcolor => [ qw/silver white/ ] }, no_ucfirst => 1 );
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 $table->output({ no_ucfirst => 1 }); # note the {}!
EXAMPLES WITH Text::Table¶
- "$result->text("neat")"
- Neither neat nor pretty, but useful for debugging. Uses DBI's
"neat_list" method. Doesn't display
column names.
'1', 'Camel', 'mammal' '2', 'Llama', 'mammal' '3', 'Owl', 'bird' '4', 'Juerd', undef
- "$result->text("table")"
- Displays a simple table using ASCII lines.
id | animal | type ---+--------+------- 1 | Camel | mammal 2 | Llama | mammal 3 | Owl | bird 4 | Juerd |
- "$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 | | +----+--------+--------+
For "table" and "box", you need Anno Siegel's Text::Table module installed.
AUTHOR¶
Juerd Waalboer <juerd@cpan.org> <http://juerd.nl/>
SEE ALSO¶
DBIx::Simple, SQL::Abstract
2010-12-03 | perl v5.16.3 |