DBIx::Simple(3) User Contributed Perl Documentation DBIx::Simple(3)NAMEDBIx::Simple - Very complete easy-to-use OO interface to DBI
SYNOPSISDBIx::Simple
$db = DBIx::Simple->connect(...) # or ->new
$db->keep_statements = 16
$db->lc_columns = 1
$db->result_class = 'DBIx::Simple::Result';
$db->begin_work $db->commit
$db->rollback $db->disconnect
$db->func(...) $db->last_insert_id
$result = $db->query(...)
DBIx::SImple + SQL::Interp
$result = $db->iquery(...)
DBIx::Simple + SQL::Abstract
$db->abstract = SQL::Abstract->new(...)
$result = $db->select(...)
$result = $db->insert(...)
$result = $db->update(...)
$result = $db->delete(...)
DBIx::Simple::Result
@columns = $result->columns
$result->into($foo, $bar, $baz)
$row = $result->fetch
@row = $result->list @rows = $result->flat
$row = $result->array @rows = $result->arrays
$row = $result->hash @rows = $result->hashes
@row = $result->kv_list @rows = $result->kv_flat
$row = $result->kv_array @rows = $result->kv_arrays
$obj = $result->object @objs = $result->objects
%map = $result->map_arrays(...)
%map = $result->map_hashes(...)
%map = $result->map
$rows = $result->rows
$dump = $result->text
$result->finish
DBIx::Simple::Result + DBIx::XHTML_Table
$html = $result->html(...)
$table_object = $result->xto(...)
Examples
Please read DBIx::Simple::Examples for code examples.
DESCRIPTIONDBIx::Simple provides a simplified interface to DBI, Perl's powerful
database module.
This module is aimed at rapid development and easy maintenance. Query
preparation and execution are combined in a single method, the result
object (which is a wrapper around the statement handle) provides easy
row-by-row and slurping methods.
The "query" method returns either a result object, or a dummy object.
The dummy object returns undef (or an empty list) for all methods and
when used in boolean context, is false. The dummy object lets you
postpone (or skip) error checking, but it also makes immediate error
checking simply "$db->query(...) or die $db->error".
DBIx::Simple methods
Class methods
"connect($dbh)", "connect($dsn, $user, $pass, \%options)"
"new($dbh)", "new($dsn, $user, $pass, \%options)"
The "connect" or "new" class method takes either an
existing DBI object ($dbh), or a list of arguments to
pass to "DBI->connect". See DBI for a detailed
description.
You cannot use this method to clone a DBIx::Simple
object: the $dbh passed should be a DBI::db object, not a
DBIx::Simple object.
For new connections, PrintError is disabled by default.
If you enable it, beware that it will report line numbers
in DBIx/Simple.pm.
For new connections, RaiseError is enabled by default
unless the environment variable
"PERL_DBIX_SIMPLE_NO_RAISEERROR" is set to a non-empty
non-0 value.
This method is the constructor and returns a DBIx::Simple
object on success. On failure, it returns undef.
Object methods
"query($query, @values)"
Prepares and executes the query and returns a result
object.
If the string "(??)" is present in the query, it is
replaced with a list of as many question marks as
@values.
The database drivers substitute placeholders (question
marks that do not appear in quoted literals) in the query
with the given @values, after them escaping them. You
should always use placeholders, and never use raw user
input in database queries.
On success, returns a DBIx::Simple::Result object. On
failure, returns a DBIx::Simple::Dummy object.
"iquery(...)" Uses SQL::Interp to interpolate values into a query, and
uses the resulting generated query and bind arguments
with "query". See SQL::Interp's documentation for usage
information.
Requires Mark Storberg's SQL::Interp, which is available
from CPAN. SQL::Interp is a fork from David Manura's
SQL::Interpolate.
"select", "insert", "update", "delete"
Calls the respective method on "abstract", and uses the
resulting generated query and bind arguments with
"query". See SQL::Abstract's documentation for usage
information. You can override the object by assigning to
the "abstract" property.
Requires Nathan Wiger's SQL::Abstract, which is available
from CPAN.
"begin_work", "begin", "commit", "rollback"
These transaction related methods call the DBI respective
methods and Do What You Mean. See DBI for details.
"begin" is an alias for "begin_work".
"func(...)" Calls the "func" method of DBI. See DBI for details.
"last_insert_id(...)"
Calls the "last_insert_id" method of DBI. See DBI for
details. Note that this feature requires DBI 1.38 or
newer.
"disconnect" Destroys (finishes) active statements and disconnects.
Whenever the database object is destroyed, this happens
automatically if DBIx::Simple handled the connection
(i.e. you didn't use an existing DBI handle). After
disconnecting, you can no longer use the database object
or any of its result objects.
Object properties
"dbh" Exposes the internal database handle. Use this only if
you know what you are doing. Keeping a reference or doing
queries can interfere with DBIx::Simple's garbage
collection and error reporting.
"lc_columns = $bool"
When true at time of query execution, makes several
result object methods use lower cased column names.
"lc_columns" is true by default.
"keep_statements = $integer"
Sets the number of statement objects that DBIx::Simple
can keep for reuse. This can dramatically speed up
repeated queries (like when used in a loop).
"keep_statements" is 16 by default.
A query is only reused if it equals a previously used one
literally. This means that to benefit from this caching
mechanism, you must use placeholders and never
interpolate variables yourself.
# Wrong:
$db->query("INSERT INTO foo VALUES ('$foo', '$bar', '$baz')");
$db->query("SELECT FROM foo WHERE foo = '$foo' OR bar = '$bar'");
# Right:
$db->query('INSERT INTO foo VALUES (??)', $foo, $bar, $baz);
$db->query('SELECT FROM foo WHERE foo = ? OR bar = ?', $foo, $baz);
Of course, automatic value escaping is a much better
reason for using placeholders.
"result_class = $string"
Class to use for result objects. Defaults to
DBIx::Simple::Result. A constructor is not used.
"error" Returns the error string of the last DBI method. See the
discussion of ""err"" and ""errstr"" in DBI.
"abstract = SQL::Abstract->new(...)"
Sets the object to use with the "select", "insert",
"update" and "delete" methods. On first access, will
create one with SQL::Abstract's default options.
Requires Nathan Wiger's SQL::Abstract, which is available
from CPAN.
In theory, you can assign any object to this property, as
long as that object has these four methods, and they
return a list suitable for use with the "query" method.
DBIx::Simple::Dummy
The "query" method of DBIx::Simple returns a dummy object on failure.
Its methods all return an empty list or undef, depending on context.
When used in boolean context, a dummy object evaluates to false.
DBIx::Simple::Result methods
Methods documented to return "a list" return a reference to an array of
the same in scalar context, unless something else is explicitly
mentioned.
"columns" Returns a list of column names. Affected by "lc_columns".
"bind(LIST)" Binds the given LIST of variables to the columns. Unlike
with DBI's "bind_columns", passing references is not
needed.
Bound variables are very efficient. Binding a tied
variable doesn't work.
"attr(...)" Returns a copy of an sth attribute (property). See
"Statement Handle Attributes" in DBI for details.
"func(...)" This calls the "func" method on the sth of DBI. See DBI
for details.
"rows" Returns the number of rows affected by the last row
affecting command, or -1 if the number of rows is not
known or not available.
For SELECT statements, it is generally not possible to
know how many rows are returned. MySQL does provide this
information. See DBI for a detailed explanation.
"finish" Finishes the statement. After finishing a statement, it
can no longer be used. When the result object is
destroyed, its statement handle is automatically finished
and destroyed. There should be no reason to call this
method explicitly; just let the result object go out of
scope.
Fetching a single row at a time
"fetch" Returns a reference to the array that holds the values.
This is the same array every time.
Subsequent fetches (using any method) may change the
values in the variables passed and the returned
reference's array.
"into(LIST)" Combines "bind" with "fetch". Returns what "fetch"
returns.
"list" Returns a list of values, or (in scalar context), only
the last value.
"array" Returns a reference to an array.
"hash" Returns a reference to a hash, keyed by column name.
Affected by "lc_columns".
"kv_list" Returns an ordered list of interleaved keys and values.
Affected by "lc_columns".
"kv_array" Returns a reference to an array of interleaved column
names and values. Like kv, but returns an array reference
even in list context. Affected by "lc_columns".
"object($class, ...)"
Returns an instance of $class. See "Object construction".
Possibly affected by "lc_columns".
Fetching all remaining rows
"flat" Returns a flattened list.
"arrays" Returns a list of references to arrays
"hashes" Returns a list of references to hashes, keyed by column
name. Affected by "lc_columns".
"kv_flat" Returns an flattened list of interleaved column names and
values. Affected by "lc_columns".
"kv_arrays" Returns a list of references to arrays of interleaved
column names and values. Affected by "lc_columns".
"objects($class, ...)"
Returns a list of instances of $class. See "Object
construction". Possibly affected by "lc_columns".
"map_arrays($column_number)"
Constructs a hash of array references keyed by the values
in the chosen column, and returns a list of interleaved
keys and values, or (in scalar context), a reference to a
hash.
"map_hashes($column_name)"
Constructs a hash of hash references keyed by the values
in the chosen column, and returns a list of interleaved
keys and values, or (in scalar context), a reference to a
hash. Affected by "lc_columns".
"map" Constructs a simple hash, using the two columns as
key/value pairs. Should only be used with queries that
return two columns. Returns a list of interleaved keys
and values, or (in scalar context), a reference to a
hash.
"xto(%attr)" Returns a DBIx::XHTML_Table object, passing the
constructor a reference to %attr.
Requires Jeffrey Hayes Anderson's DBIx::XHTML_Table,
which is available from CPAN.
In general, using the "html" method (described below) is
much easier. "xto" is available in case you need more
flexibility. Not affected by "lc_columns".
"html(%attr)" Returns an (X)HTML formatted table, using the
DBIx::XHTML_Table module. Passes a reference to %attr to
both the constructor and the "output" method.
Requires Jeffrey Hayes Anderson's DBIx::XHTML_Table,
which is available from CPAN.
This method is a shortcut method. That means that
$result->html
$result->html(
tr => { bgcolor => [ 'silver', 'white' ] },
no_ucfirst => 1
)
do the same as:
$result->xto->output
$result->xto(
tr => { bgcolor => [ 'silver', 'white' ] }
)->output(
no_ucfirst => 1
);
"text($type)" Returns a string with a simple text representation of the
data. $type can be any of: "neat", "table", "box". It
defaults to "table" if Text::Table is installed, to
"neat" if it isn't.
"table" and "box" require Anno Siegel's Text::Table,
which is available from CPAN.
Object construction
DBIx::Simple has basic support for returning results as objects. The
actual construction method has to be provided by the chosen class,
making this functionality rather advanced and perhaps unsuited for
beginning programmers.
When the "object" or "objects" method is called on the result object
returned by one of the query methods, two approaches are tried. In
either case, pass the name of a class as the first argument. A prefix
of a single colon can be used as an alias for "DBIx::Simple::Result::",
e.g. ":Example" is short for "DBIx::Simple::Result::Example". When this
shortcut is used, the corresponding module is loaded automatically.
The default class when no class is given, is ":RowObject". It requires
Jos Boumans' Object::Accessor, which is available from CPAN.
Simple object construction
When "object" is given a class that provides a "new" method, but not a
"new_from_dbix_simple" method, "new" is called with a list of
interleaved column names and values, like a flattened hash, but
ordered. "objects" causes "new" to be called multiple times, once for
each remaining row.
Example:
{
package DBIx::Simple::Result::ObjectExample;
sub new {
my ($class, %args) = @_;
return bless $class, \%args;
}
sub foo { ... }
sub bar { ... }
}
$db->query('SELECT foo, bar FROM baz')->object(':ObjectExample')->foo();
Advanced object construction
When "object" or "objects" is given a class that provides a
"new_from_dbix_simple" method, any "new" is ignored, and
"new_from_dbix_simple" is called with a list of the
DBIx::Simple::Result object and any arguments passed to "object" or
"objects".
"new_from_dbix_simple" is called in scalar context for "object", and in
list context for "objects". In scalar context, it should fetch exactly
one row, and in list context, it should fetch all remaining rows.
Example:
{
package DBIx::Simple::Result::ObjectExample;
sub new_from_dbix_simple {
my ($class, $result, @args) = @_;
return map { bless $class, $_ } $result->hashes if wantarray;
return bless $class, $result->hash;
}
sub foo { ... }
sub bar { ... }
}
$db->query('SELECT foo, bar FROM baz')->object(':ObjectExample')->foo();
MISCELLANEOUS
The mapping methods do not check whether the keys are unique. Rows that
are fetched later overwrite earlier ones.
LICENSE
Pick your favourite OSI approved license :)
http://www.opensource.org/licenses/alphabetical
AUTHOR
Juerd Waalboer <#####@juerd.nl> <http://juerd.nl/>
SEE ALSO
perl, perlref
DBI, DBIx::Simple::Examples, SQL::Abstract, DBIx::XHTML_Table
perl v5.16.1 2011-01-04 DBIx::Simple(3)