Codebase list liborlite-perl / upstream/1.25
upstream/1.25

Tree @upstream/1.25 (Download .tar.gz)

NAME
    ORLite - Extremely light weight SQLite-specific ORM

SYNOPSIS
      package Foo;

      use strict;
      use ORLite 'data/sqlite.db';

      my @awesome = Foo::Person->select(
         'where first_name = ?',
         'Adam',
      );

DESCRIPTION
    SQLite is a light single file SQL database that provides an excellent
    platform for embedded storage of structured data.

    However, while it is superficially similar to a regular server-side SQL
    database, SQLite has some significant attributes that make using it like
    a traditional database difficult.

    For example, SQLite is extremely fast to connect to compared to server
    databases (1000 connections per second is not unknown) and is
    particularly bad at concurrency, as it can only lock transactions at a
    database-wide level.

    This role as a superfast internal data store can clash with the roles
    and designs of traditional object-relational modules like Class::DBI or
    DBIx::Class.

    What this situation would seem to need is an object-relation system that
    is designed specifically for SQLite and is aligned with its
    idiosyncracies.

    ORLite is an object-relation system specifically tailored for SQLite
    that follows many of the same principles as the ::Tiny series of modules
    and has a design and feature set that aligns directly to the
    capabilities of SQLite.

    Further documentation will be available at a later time, but the
    synopsis gives a pretty good idea of how it works.

How it Works
    In short, ORLite discovers the schema of a SQLite database, and then
    uses code generation to build a set of packages for talking to that
    database.

    In the simplest form, your target root package "uses" ORLite, which will
    do the schema discovery and code generation at compile-time.

    When called, ORLite generates two types of package.

    Firstly, it builds database connectivity, transaction support, and other
    purely database level functionality into your root namespace.

    Then it will create one sub-package underneath the root package for each
    table contained in the database.

ROOT PACKAGE METHODS
    All ORLite root packages receive an identical set of methods for
    controlling connections to the database, transactions, and the issueing
    of queries of various types to the database.

    The example root package Foo::Bar is used in any examples.

    All methods are static, ORLite does not allow the creation of a Foo::Bar
    object (although you may wish to add this capability yourself).

  dsn
      my $string = Foo::Bar->dsn;

    The "dsn" accessor returns the dbi connection string used to connect to
    the SQLite database as a string.

  dbh
      my $handle = Foo::Bar->dbh;

    To reliably prevent potential SQLite deadlocks resulting from multiple
    connections in a single process, each ORLite package will only ever
    maintain a single connection to the database.

    During a transaction, this will be the same (cached) database handle.

    Although in most situations you should not need a direct DBI connection
    handle, the "dbh" method provides a method for getting a direct
    connection in a way that is compatible with ORLite's connection
    management.

    Please note that these connections should be short-lived, you should
    never hold onto a connection beyond the immediate scope.

    The transaction system in ORLite is specifically designed so that code
    using the database should never have to know whether or not it is in a
    transation.

    Because of this, you should never call the ->disconnect method on the
    database handles yourself, as the handle may be that of a currently
    running transaction.

    Further, you should do your own transaction management on a handle
    provided by the <dbh> method.

    In cases where there are extreme needs, and you absolutely have to
    violate these connection handling rules, you should create your own
    completely manual DBI->connect call to the database, using the connect
    string provided by the "dsn" method.

    The "dbh" method returns a DBI::db object, or throws an exception on
    error.

  begin
      Foo::Bar->begin;

    The "begin" method indicates the start of a transaction.

    In the same way that ORLite allows only a single connection, likewise it
    allows only a single application-wide transaction.

    No indication is given as to whether you are currently in a transaction
    or not, all code should be written neutrally so that it works either way
    or doesn't need to care.

    Returns true or throws an exception on error.

  commit
      Foo::Bar->commit;

    The "commit" method commits the current transaction. If called outside
    of a current transaction, it is accepted and treated as a null
    operation.

    Once the commit has been completed, the database connection falls back
    into auto-commit state. If you wish to immediately start another
    transaction, you will need to issue a separate ->begin call.

    Returns true or throws an exception on error.

  rollback
    The "rollback" method rolls back the current transaction. If called
    outside of a current transaction, it is accepted and treated as a null
    operation.

    Once the rollback has been completed, the database connection falls back
    into auto-commit state. If you wish to immediately start another
    transaction, you will need to issue a separate ->begin call.

    If a transaction exists at END-time as the process exits, it will be
    automatically rolled back.

    Returns true or throws an exception on error.

  do
      Foo::Bar->do('insert into table (foo, bar) values (?, ?)', {},
          $foo_value,
          $bar_value,
      );

    The "do" method is a direct wrapper around the equivalent DBI method,
    but applied to the appropriate locally-provided connection or
    transaction.

    It takes the same parameters and has the same return values and error
    behaviour.

  selectall_arrayref
    The "selectall_arrayref" method is a direct wrapper around the
    equivalent DBI method, but applied to the appropriate locally-provided
    connection or transaction.

    It takes the same parameters and has the same return values and error
    behaviour.

  selectall_hashref
    The "selectall_hashref" method is a direct wrapper around the equivalent
    DBI method, but applied to the appropriate locally-provided connection
    or transaction.

    It takes the same parameters and has the same return values and error
    behaviour.

  selectcol_arrayref
    The "selectcol_arrayref" method is a direct wrapper around the
    equivalent DBI method, but applied to the appropriate locally-provided
    connection or transaction.

    It takes the same parameters and has the same return values and error
    behaviour.

  selectrow_array
    The "selectrow_array" method is a direct wrapper around the equivalent
    DBI method, but applied to the appropriate locally-provided connection
    or transaction.

    It takes the same parameters and has the same return values and error
    behaviour.

  selectrow_arrayref
    The "selectrow_arrayref" method is a direct wrapper around the
    equivalent DBI method, but applied to the appropriate locally-provided
    connection or transaction.

    It takes the same parameters and has the same return values and error
    behaviour.

  selectrow_hashref
    The "selectrow_hashref" method is a direct wrapper around the equivalent
    DBI method, but applied to the appropriate locally-provided connection
    or transaction.

    It takes the same parameters and has the same return values and error
    behaviour.

  prepare
    The "prepare" method is a direct wrapper around the equivalent DBI
    method, but applied to the appropriate locally-provided connection or
    transaction

    It takes the same parameters and has the same return values and error
    behaviour.

    In general though, you should try to avoid the use of your own prepared
    statements if possible, although this is only a recommendation and by no
    means prohibited.

  pragma
      # Get the user_version for the schema
      my $version = Foo::Bar->pragma('user_version');

    The "pragma" method provides a convenient method for fetching a pragma
    for a datase. See the SQLite documentation for more details.

TABLE PACKAGE METHODS
    The example root package Foo::Bar::TableName is used in any examples.

    TO BE COMPLETED

TO DO
    - Support for intuiting reverse relations from foreign keys

    - Document the 'create' and 'table' params

SUPPORT
    Bugs should be reported via the CPAN bug tracker at

    <http://rt.cpan.org/NoAuth/ReportBug.html?Queue=ORLite>

    For other issues, contact the author.

AUTHOR
    Adam Kennedy <adamk@cpan.org>

SEE ALSO
    ORLite::Mirror, ORLite::Migrate

COPYRIGHT
    Copyright 2008 - 2009 Adam Kennedy.

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    The full text of the license can be found in the LICENSE file included
    with this module.