NAME
DBIO::Storage - Generic Storage Handler
VERSION
version 0.900000
DESCRIPTION
DBIO::Storage is the abstract base class for storage backends. It contains the generic transaction, exception, and cursor plumbing shared by concrete storage implementations.
Most real applications use DBIO::Storage::DBI or a driver-specific subclass such as PostgreSQL, MySQL, or SQLite storage. This module is where the common storage contract is defined.
METHODS
new
Arguments: $schema
Instantiates the Storage object.
new
set_schema
throw_exception
txn_do
txn_begin
txn_commit
txn_rollback
_throw_deferred_rollback
svp_begin
_svp_generate_name
svp_release
svp_rollback
txn_scope_guard
debugfh
debugobj
debugcb
register_type
DBIO::PostgreSQL::Storage->register_type('jsonb', {
cake_options => [qw(inflate_json inflate_jsonb)],
components => ['InflateColumn::Serializer'],
col_attrs => { serializer_class => 'JSON' },
});Registers type metadata for use by DBIO::Cake and other DBIO subsystems. Driver distributions call this in their module body to declare how their specific types should be handled. Subclass registrations inherit from and can override parent class registrations via normal MRO lookup.
type_info
my $info = DBIO::PostgreSQL::Storage->type_info('jsonb');Returns the type metadata for a given type name, walking up the MRO so subclasses inherit and can override base type definitions. Returns undef if the type is not registered.
all_type_names
my @types = DBIO::PostgreSQL::Storage->all_type_names;Returns all type names registered for this class and its ancestors (deduplicated, most-derived class wins).
set_schema
Used to reset the schema class or object which owns this storage object, such as during "clone" in DBIO::Schema.
set_access_broker
Attach an DBIO::AccessBroker instance to this storage and set the default broker mode (defaults to write).
clear_access_broker
Detach any currently attached broker from this storage.
current_access_broker_connect_info
Return the current storage-native connect info for the requested mode.
connected
Returns true if we have an open storage connection, false if it is not (yet) open.
disconnect
Closes any open storage connection unconditionally.
ensure_connected
Initiate a connection to the storage if one isn't already open.
throw_exception
Throws an exception - croaks.
txn_do
Executes $coderef with (optional) arguments @coderef_args atomically, returning its result (if any). If an exception is caught, a rollback is issued and the exception is rethrown. If the rollback fails, (i.e. throws an exception) an exception is thrown that includes a "Rollback failed" message.
For example,
my $author_rs = $schema->resultset('Author')->find(1);
my @titles = qw/Night Day It/;
my $coderef = sub {
# If any one of these fails, the entire transaction fails
$author_rs->create_related('books', {
title => $_
}) foreach (@titles);
return $author->books;
};
my $rs;
try {
$rs = $schema->txn_do($coderef);
} catch {
my $error = shift;
# Transaction failed
die "something terrible has happened!"
if ($error =~ /Rollback failed/); # Rollback failed
deal_with_failed_transaction();
};In a nested transaction (calling txn_do() from within a txn_do() coderef) only the outermost transaction will issue a "txn_commit", and txn_do() can be called in void, scalar and list context and it will behave as expected.
Please note that all of the code in your coderef, including non-DBIO code, is part of a transaction. This transaction may fail out halfway, or it may get partially double-executed (in the case that our DB connection failed halfway through the transaction, in which case we reconnect and restart the txn). Therefore it is best that any side-effects in your coderef are idempotent (that is, can be re-executed multiple times and get the same result), and that you check up on your side-effects in the case of transaction failure.
txn_begin
Starts a transaction.
See the preferred "txn_do" method, which allows for an entire code block to be executed transactionally.
txn_commit
Issues a commit of the current transaction.
It does not perform an actual storage commit unless there's a DBIO transaction currently in effect (i.e. you called "txn_begin").
txn_rollback
Issues a rollback of the current transaction (or savepoint, if auto_savepoint is enabled, and you are in a nested transaction).
If you are in a nested transaction without auto_savepoint, rollback will put the storage into a "deferred rollback" state and throw a DBIO::Storage::NESTED_ROLLBACK_EXCEPTION exception to help you unwind to the outer-most transaction's scope. Until the "deferred rollback" condition is resolved, the storage engine will throw exceptions on any attempt to begin, commit, or rollback a transaction.
svp_begin
Arguments: $savepoint_name?
Created a new savepoint using the name provided as argument. If no name is provided, a random name will be used.
svp_release
Arguments: $savepoint_name?
Release the savepoint provided as argument. If none is provided, release the savepoint created most recently. This will implicitly release all savepoints created after the one explicitly released as well.
svp_rollback
Arguments: $savepoint_name?
Rollback to the savepoint provided as argument. If none is provided, rollback to the savepoint created most recently. This will implicitly release all savepoints created after the savepoint we rollback to.
txn_scope_guard
An alternative way of transaction handling based on DBIO::Storage::TxnScopeGuard:
my $txn_guard = $storage->txn_scope_guard;
$result->col1("val1");
$result->update;
$txn_guard->commit;If an exception occurs, or the guard object otherwise leaves the scope before $txn_guard->commit is called, the transaction will be rolled back by an explicit "txn_rollback" call. In essence this is akin to using a "txn_begin"/"txn_commit" pair, without having to worry about calling "txn_rollback" at the right places. Note that since there is no defined code closure, there will be no retries and other magic upon database disconnection. If you need such functionality see "txn_do".
sql_maker
Returns a sql_maker object - normally an object of class DBIO::SQLMaker.
debug
Causes trace information to be emitted on the "debugobj" object. (or STDERR if "debugobj" has not specifically been set).
This is the equivalent to setting DBIO_TRACE in your shell environment.
debugfh
An opportunistic proxy to ->debugobj->debugfh(@_) If the currently set "debugobj" does not have a "debugfh" method, caling this is a no-op.
debugobj
Sets or retrieves the object used for metric collection. Defaults to an instance of DBIO::Storage::Statistics that is compatible with the original method of using a coderef as a callback. See the aforementioned Statistics class for more information.
debugcb
Sets a callback to be executed each time a statement is run; takes a sub reference. Callback is executed as $sub->($op, $info) where $op is SELECT/INSERT/UPDATE/DELETE and $info is what would normally be printed.
See "debugobj" for a better way.
cursor_class
The cursor class for this Storage object.
deploy
Deploy the tables to storage (CREATE TABLE and friends in a SQL-based Storage class). This would normally be called through "deploy" in DBIO::Schema.
connect_info
The arguments of connect_info are always a single array reference, and are Storage-handler specific.
This is normally accessed via "connection" in DBIO::Schema, which encapsulates its argument list in an arrayref before calling connect_info here.
select
Handle a select statement.
insert
Handle an insert statement.
update
Handle an update statement.
delete
Handle a delete statement.
select_single
Performs a select, fetch and return of data - handles a single row only.
select_async
Async variant of "select". Returns a DBIO::Future that resolves with the query results. Default implementation executes synchronously and returns an immediately-resolved Future via "future_class".
select_single_async
Async variant of "select_single".
insert_async
Async variant of "insert".
update_async
Async variant of "update".
delete_async
Async variant of "delete".
txn_do_async
Async variant of "txn_do". Returns a DBIO::Future that resolves after COMMIT or rejects after ROLLBACK.
future_class
Returns the class name used to construct Future objects. Defaults to DBIO::Test::Future which resolves synchronously. Async storage drivers override this to return their event loop's Future class.
columns_info_for
Returns metadata for the given source's columns. This is *deprecated*, and will be removed before 1.0. You should be specifying the metadata yourself if you need it.
ENVIRONMENT VARIABLES
DBIO_TRACE
If DBIO_TRACE is set then trace information is produced (as when the "debug" method is set).
If the value is of the form 1=/path/name then the trace output is written to the file /path/name.
This environment variable is checked when the storage object is first created (when you call connect on your schema). So, run-time changes to this environment variable will not take effect unless you also re-connect on your schema.
DBIO_TRACE_PROFILE
If DBIO_TRACE_PROFILE is set, DBIO::Storage::Debug::PrettyTrace will be used to format the output from DBIO_TRACE. The value it is set to is the profile that it will be used. If the value is a filename the file is read with Config::Any and the results are used as the configuration for tracing. See "new" in SQL::Abstract::Tree for what that structure should look like.
SEE ALSO
DBIO::Storage::DBI - reference storage implementation using DBI and a subclass of SQL::Abstract ( or similar )
1;
AUTHOR
DBIO & DBIx::Class Authors
COPYRIGHT AND LICENSE
Copyright (C) 2026 DBIO Authors Portions Copyright (C) 2005-2025 DBIx::Class Authors Based on DBIx::Class, heavily modified.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.