view release on metacpan or  search on metacpan

lib/DBI/SQL/Nano.pm  view on Meta::CPAN

    * a parens delimited, comma-separated list of values which can be:
       * placeholders (an unquoted question mark)
       * numbers (unquoted numbers)
       * column names (unquoted strings)
       * nulls (unquoted word NULL)
       * strings (delimited with single quote marks);
       * note: leading and trailing percent mark (%) and underscore (_)
         can be used as wildcards in quoted strings for use with
         the LIKE and CLIKE operators
       * note: escaped single quotation marks within strings are not
         supported, neither are embedded commas, use placeholders instead

  set_clause ::=
    * a comma-separated list of column = value pairs
    * see val_list for acceptable value formats

  where_clause ::=
    * a single "column/value <op> column/value" predicate, optionally
      preceded by "NOT"
    * note: multiple predicates combined with ORs or ANDs are not supported
    * see val_list for acceptable value formats
    * op may be one of:
         < > >= <= = <> LIKE CLIKE IS
    * CLIKE is a case insensitive LIKE

  order_clause ::= column_name [ASC|DESC]
    * a single column optional ORDER BY clause is supported
    * as in standard SQL, if neither ASC (ascending) nor
      DESC (descending) is specified, ASC becomes the default

=head1 TABLES

DBI::SQL::Nano::Statement operates on exactly one table. This table will be
opened by inherit from DBI::SQL::Nano::Statement and implements the
C<< open_table >> method.

  sub open_table ($$$$$)
  {
      ...
      return Your::Table->new( \%attributes );
  }

DBI::SQL::Nano::Statement_ expects a rudimentary interface is implemented by
the table object, as well as SQL::Statement expects.

  package Your::Table;

  our @ISA = qw(DBI::SQL::Nano::Table);

  sub drop ($$)        { ... }
  sub fetch_row ($$$)  { ... }
  sub push_row ($$$)   { ... }
  sub push_names ($$$) { ... }
  sub truncate ($$)    { ... }
  sub seek ($$$$)      { ... }

The base class interfaces are provided by DBI::SQL::Nano::Table_ in case of
relying on DBI::SQL::Nano or SQL::Eval::Table (see L<SQL::Eval> for details)
otherwise.

=head1 BUGS AND LIMITATIONS

There are no known bugs in DBI::SQL::Nano::Statement. If you find a one
and want to report, please see L<DBI> for how to report bugs.

DBI::SQL::Nano::Statement is designed to provide a minimal subset for
executing SQL statements.

The most important limitation might be the restriction on one table per
statement. This implies, that no JOINs are supported and there cannot be
any foreign key relation between tables.

The where clause evaluation of DBI::SQL::Nano::Statement is very slow
(SQL::Statement uses a precompiled evaluation).

INSERT can handle only one row per statement. To insert multiple rows,
use placeholders as explained in DBI.

The DBI::SQL::Nano parser is very limited and does not support any
additional syntax such as brackets, comments, functions, aggregations
etc.

In contrast to SQL::Statement, temporary tables are not supported.

=head1 ACKNOWLEDGEMENTS

Tim Bunce provided the original idea for this module, helped me out of the
tangled trap of namespaces, and provided help and advice all along the way.
Although I wrote it from the ground up, it is based on Jochen Wiedmann's
original design of SQL::Statement, so much of the credit for the API goes
to him.

=head1 AUTHOR AND COPYRIGHT

This module is originally written by Jeff Zucker < jzucker AT cpan.org >

This module is currently maintained by Jens Rehsack < jrehsack AT cpan.org >

Copyright (C) 2010 by Jens Rehsack, all rights reserved.
Copyright (C) 2004 by Jeff Zucker, all rights reserved.

You may freely distribute and/or modify this module under the terms of
either the GNU General Public License (GPL) or the Artistic License,
as specified in the Perl README file.

=cut