NAME

       Padre::DB - An ORLite-based ORM Database API

SYNOPSIS

       TO BE COMPLETED

DESCRIPTION

       This module implements access to the database that Padre is using to store bits & pieces.
       It is using "ORLite" underneath, for an easy table scheme discovery at runtime. See below
       to learn about how to update the database scheme.

   Updating database scheme
       The database is created at runtime if it does not exist, but we are relying on
       "Padre::DB::Migrate". To summarize "Padre::DB::Migrate":

       •   We provide scripts to update the database from one revision to another.

       •   "Padre::DB" calls "Padre::DB::Migrate" to apply them in order, starting from the
           current database revision.

       Therefore, in order to update the database, you need to do the following:

       •   Create a script share/timeline/migrate-$i.pl with $i the next available integer. This
           script will look like this:

                   use strict;
                   use Padre::DB::Migrate::Patch;

                   # do some stuff on the base
                   do(<<'END_SQL');
                   <insert your sql statement here>
                   END_SQL

           Of course, in case of dropping an existing table, you should make sure that you don't
           loose data - that is, your script should migrate existing data to the new scheme
           (unless the whole feature is deprecated, of course).

       •   Update the user_revision in "Padre::DB"'s call to "Padre::DB::Migrate" to read the new
           script number (i.e., the $i that you have used to name your script in the timeline
           directory).

                   use Padre::DB::Migrate 0.01 {
                       [...]
                           user_revision => <your-revision-number>,
                       [...]
                   };

       •   Once this is done, you can try to load Padre's development and check whether the table
           is updated correctly. Once again, check whether data is correctly migrated from old
           scheme to new scheme (if applicable).

           Note that "Padre::DB::Migrate" is quiet by default. And if your SQL statements are
           buggy, you will not see anything but the database not being updated. Therefore, to
           debug what's going on, add the "-DEBUG" flag to "Padre::DB::Migrate" call (add it as
           the last parameter):

                   use Padre::DB::Migrate 0.01 {
                       [...]
                   }, '-DEBUG'

       Congratulations! The database has been updated, and will be updated automatically when
       users will run the new Padre version...

   Accessing and using the database
       Now that the database has been updated, you can start using it. Each new table will have a
       "Padre::DB::YourTable" module created automatically at runtime by "ORLite", providing you
       with the standard methods described below (see METHODS).

       Note: we prefer using underscore for table names instead of camel case.  "ORLite" is smart
       enough to convert underscore names to camel case module names.

       But what if you want to provide some particular methods? For example, one can imagine that
       if you create a table "accessed_files" retaining the path and the opening timestamp, you
       want to create a method "most_recent()" that will return the last opened file.

       In that case, that's quite easy, too:

       •   Create a standard "Padre::DB::YourTable" module where you will put your method. Note
           that all standard methods described above will still be available.

       •   Don't forget to "use Padre::DB::YourTable" in "Padre::DB", so that other Padre modules
           will get access to all db tables by just using "Padre::DB".

METHODS

       Those methods are automatically created for each of the tables (see above). Note that the
       modules automatically created provide both class methods and instance methods, where the
       object instances each represent a table record.

   dsn
         my $string = Padre::DB->dsn;

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

   dbh
         my $handle = Padre::DB->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
       connection management in ORLite.

       Please note that these connections should be short-lived, you should never hold onto a
       connection beyond your 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
         Padre::DB->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
         Padre::DB->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
         Padre::DB->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 = Padre::DB->pragma('user_version');

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

SUPPORT

       Padre::DB is based on ORLite.

       Documentation created by ORLite::Pod 0.10.

       For general support please see the support section of the main project documentation.

AUTHOR

       Adam Kennedy <adamk@cpan.org>

COPYRIGHT

       Copyright 2008-2013 The Padre development team as listed in Padre.pm.

       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.