Createtrivialschema

NAME

DBIx::Admin::CreateTrivialSchema - Create a set of SQL create statements, and execute them

Synopsis

	use DBIx::Admin::CreateTrivialSchema;

	DBIx::Admin::CreateTrivialSchema -> new
	(
	    dbh      => $dbh,
	    not_null => 1,
	    schema   => {t_a => [col_a, col_b], t_z => [col_z]},
	    type     => 'char(2)',
	    verbose  => 1,
	);

Description

DBIx::Admin::CreateTrivialSchema is a pure Perl module.

Given a hashref of tables and columns per table, it creates SQL create statements, and executes them.

The above schema would create and execute these SQL statements:

• create table t_a (col_a char(2) not null, col_b char(2) not null)
• create table t_z (col_z char(2) not null)

Any pre-existing tables with the same names are dropped first. Ensure your backups are up-to-date!

It should be obvious that this module is mindless in that all columns in all tables are given the same type, the same 'not null' option, and the same default value.

This module is designed to use the output of DBIx::Admin::BackupRestore V 1.07's sub get_column_names(), which you can call after running that module's sub backup.

So, the combined effect of these 2 modules is that you backup a database to XML with DBIx::Admin::BackupRestore, and then use DBIx::Admin::CreateTrivialSchema to create a trivial schema into which you jam the backed-up data with DBIx::Admin::BackupRestore's sub restore.

This enables you to get the data into some sort of schema when the create statements used to create the original schema are not available on the target platform. For instance, use this technique when you want to dump data from MS Access into Postgres under GNU/Linux.

This module is recommended instead of my previous attempt: DBIx::MSAccess::Convert2Db.

See also: http://savage.net.au/Ron/html/msaccess2rdbms.html

For a more sophisticated migration technique, see:

http://dev.mysql.com/tech-resources/articles/migrating-from-microsoft.html

Distributions

This module is available both as a Unix-style distro (*.tgz) and an ActiveState-style distro (*.ppd). The latter is shipped in a *.zip file.

See http://savage.net.au/Perl-modules.html for details.

See http://savage.net.au/Perl-modules/html/installing-a-module.html for help on unpacking and installing each type of distro.

Constructor and initialization

new(...) returns an object of type DBIx::Admin::CreateTrivialSchema.

This is the class's contructor.

Usage: DBIx::Admin::CreateTrivialSchema -> new().

This method takes a set of parameters.

For each parameter you wish to use, call new as new(param_1 => value_1, ...).

• dbh

  This is a database handle.

  The generated SQL will be executed against this handle.

  This parameter is mandatory.

• default

  This parameter takes a value to be inserted into the create statement, which specifies the default value you want for all columns.

  A value of 99, which matches /^\d+$/, means generate this code:

  create table t (column_a varchar(255) default 99).

  Notice how the value you supply is inserted without quotes, because it matched /^\d+$/.

  A value of '-' means generate this code:

  create table t (column_a varchar(255) default "-").

  Notice how the value you supply, if not all digits, is put inside double quotes.

  Do not provide a value of ", because it simply won't work.

  The default value is undef, which means the default clause is not inserted into the SQL.

  This parameter is optional.

• not_null

  This paramater takes the values 0 and 1, where 0 means do not insert a 'not null' clause into the SQL, and 1 means insert ' not null' into the generated SQL.

  The default value is 0.

  This parameter is optional.

• schema

  This is a hash ref whose keys are the table names, and whose values are array refs of column names.

  See the Synopsis for an example.

  The default value is {}.

  This parameter is mandatory.

• type

  This parameter takes a string to be inserted into the create statement, which specifies the data type of all columns.

  The default value is 'varchar(255)'.

  This parameter is optional.

• verbose

  This paramater takes the values 0 and 1, where 0 means do not print anything to STDERR, and 1 means print the generated SQL.

  The default value is 0.

  This parameter is optional.

Required Modules

• Carp

Changes

See Changes.txt.

Author

DBIx::Admin::CreateTrivialSchema was written by Ron Savage in 2005.

Home page: http://savage.net.au/index.html

Copyright

Australian copyright © 2005, Ron Savage. All rights reserved.

	All Programs of mine are 'OSI Certified Open Source Software';
	you can redistribute them and/or modify them under the terms of
	The Artistic License, a copy of which is available at:
	http://www.opensource.org/licenses/index.html