DBIx/Simple version 0.02
========================
INSTALLATION
To install this module do the following:
Download the .tar.gz
Unpack the .tar.gz,
Type:
perl Makefile.PL
make
make test
make install
Or, with the wonderful CPANPLUS module, just type in its shell:
i DBIx::Simple
COPYRIGHT AND LICENSE
Use this module the way you want to use it, but if anything goes wrong,
it's not my fault :)
Copyright (C) 2002 J. Waalboer
__POD2TEXT__
NAME
DBIx::Simple - An easy-to-use, object oriented interface to DBI
SYNOPSIS
General
#!/usr/bin/perl -w
use strict;
use DBIx::Simple;
my $db = DBIx::Simple->connect(
'DBI:mysql:database=test', # DBI source specification
'test', 'test', # Username and password
{ RaiseError => 1 } # Additional options
);
# Abstracted example: $db->query($query, @variables)->what_you_want;
Simple Queries
$db->query('DELETE FROM foo WHERE id = ?', $id);
die $db->{reason} if not $db->{success};
for (1..100) {
$db->query(
'INSERT INTO randomvalues VALUES (?, ?)',
int rand(10),
int rand(10)
);
}
$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;
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 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 => $name }
DESCRIPTION
This module is aimed at ease of use, not at SQL abstraction or
efficiency. The only thing this module does is provide a bone easy
interface to the already existing DBI module. With DBIx::Simple, the
terms dbh and sth are not used in the documentation (except for this
description), although they're omnipresent in the module's source. You
don't have to think about them.
A query returns a result object, that can be used directly to pick the
sort of output you want. There's no need to check if the query succeeded
in between calls, you can stack them safely, and check for success
later. This is because failed queries have dummy results, objects of
which all methods return undef.
DBIx::Simple object methods
"DBIx::Simple->connect( ... )"
This argument takes the exact arguments a normal
"DBI->connect" would take. It's the constructor method, and it
returns a new DBIx::Simple object. See also DBI.
"query($query, @values)"
This calls DBI's "prepare" and "execute" methods, passing the
values along to replace "?" placeholders. "query" returns a
new DBIx::Simple::Result object (or DBIx::Simple::Dummy), that
can be used immediately to get data out of it. You should
always use placeholders instead of the variables themselves,
as DBI will automatically quote and escape the values.
DBIx::Simple provides an omniholder placeholder that will
expand to "(?, ?, ...)" with as many question marks as
@values. There can be only one omniholder, and since it uses
all given values, you shouldn't combine it with normal
placeholders. This feature was inspired by the EZDBI module.
"omniholder($new_value)"
This sets the omniholder string. Use "undef" or an empty
string to disable this feature. Please note that the given
$new_value is not a regex. The default omniholder is "(??)".
"commit", "rollback"
These just call the DBI methods and Do What You Mean.
"disconnect"
Does What You Mean. Also note that the connection is
automatically terminated when the object is destroyed ("undef
$db" to do so explicitly), and that all statements are also
finished when the object is destroyed. "disconnect" Does not
destroy the object.
DBIx::Simple::Result object methods
"new" The constructor should only be called internally, by
DBIx::Simple itself. Some simple minded garbage collection is
done in DBIx::Simple, and you shouldn't be directly creating
your own result objects. The curious are encouraged to read
the module's source code to find out what the arguments to
"new" are.
"list" "list" Returns a list of elements in a single row. This is
like a dereferenced "$result->array". In scalar context,
returns only the first value of the row.
"array" and "hash"
These methods return a single row, in an array reference, or a
hash reference, respectively. Internally, "fetchrow_arrayref"
or "fetchrow_hashref" is used.
"flat" "flat" Returns a list of all returned fields, flattened. This
can be very useful if you select a single column. Consider
"flat" to be "list"'s plural.
"arrays" and "hashes"
These methods return a list of rows of array or hash
references. Internally, "fetchall_arrayref" is dereferenced,
or a lot of "fetchrow_hashref" returns are accumulated.
"map_arrays($column_number)" and "map_hashes($column_name)"
These methods build a hash, with the chosen column as keys,
and the remaining columns in array or hash references as
values. For "map_arrays", the column number is optional and
defaults to 0 (the first column). The methods return a
reference to the built hash.
"map" Returns a reference to a hash that was built using the first
two columns as key/value pairs. Use this only if your query
returns two values per row (other values will be discarded).
"rows" Returns the number of rows. This function calls DBI's rows
method, and may not do what you want. See DBI for a good
explanation.
finish? There is no finish method. To finish the statement, just let
the object go out of scope (you should always use "my", and
"use strict") or destroy it explicitly using "undef $result".
FEEDBACK
I'd like to hear from you what you think about DBIx::Simple, and if it
has made your life easier :). If you find serious bugs, let me know. If
you think an important feature is missing, let me know (but I'm not
going to implement functions that aren't used a lot, or that are only
for effeciency, because this module has only one goal: simplicity). My
email address can be found near the end of this document.
BUGS
Nothing is perfect, but let's try to create perfect things. Of course,
this module shares all DBI bugs. If you want to report a bug, please try
to find out if it's DBIx::Simple's fault or DBI's fault first, and don't
report DBI bugs to me.
Note: the map functions do not check if the key values are unique. If
they are not, keys are overwritten.
DISCLAIMER
No warranty, no guarantees. I hereby disclaim all responsibility for
what might go wrong.
AUTHOR
Juerd <juerd@cpan.org>
SEE ALSO
DBI