DBIx::DBSchema - Database-independent schema objects

NAME

DBIx::DBSchema - Database-independent schema objects

SYNOPSIS

  use DBIx::DBSchema;

  $schema = new DBIx::DBSchema @dbix_dbschema_table_objects;
  $schema = new_odbc DBIx::DBSchema $dbh;
  $schema = new_odbc DBIx::DBSchema $dsn, $user, $pass;
  $schema = new_native DBIx::DBSchema $dbh;
  $schema = new_native DBIx::DBSchema $dsn, $user, $pass;

  $schema->save("filename");
  $schema = load DBIx::DBSchema "filename";

  $schema->addtable($dbix_dbschema_table_object);

  @table_names = $schema->tables;

  $DBIx_DBSchema_table_object = $schema->table("table_name");

  @sql = $schema->sql($dbh);
  @sql = $schema->sql($dsn, $username, $password);
  @sql = $schema->sql($dsn); #doesn't connect to database - less reliable

  $perl_code = $schema->pretty_print;
  %hash = eval $perl_code;
  use DBI qw(:sql_types); $schema = pretty_read DBIx::DBSchema \%hash;

DESCRIPTION

DBIx::DBSchema objects are collections of DBIx::DBSchema::Table objects and represent a database schema.

This module implements an OO-interface to database schemas. Using this module, you can create a database schema with an OO Perl interface. You can read the schema from an existing database. You can save the schema to disk and restore it a different process. Most importantly, DBIx::DBSchema can write SQL CREATE statements statements for different databases from a single source.

Currently supported databases are MySQL and PostgreSQL. Sybase support is partially implemented. DBIx::DBSchema will attempt to use generic SQL syntax for other databases. Assistance adding support for other databases is welcomed. See the DBIx::DBSchema::DBD manpage, ``Driver Writer's Guide and Base Class''.

METHODS

new TABLE_OBJECT, TABLE_OBJECT, ...

Creates a new DBIx::DBSchema object.

new_odbc DATABASE_HANDLE | DATA_SOURCE USERNAME PASSWORD [ ATTR ]

Creates a new DBIx::DBSchema object from an existing data source, which can be specified by passing an open DBI database handle, or by passing the DBI data source name, username, and password. This uses the experimental DBI type_info method to create a schema with standard (ODBC) SQL column types that most closely correspond to any non-portable column types. Use this to import a schema that you wish to use with many different database engines. Although primary key and (unique) index information will only be read from databases with DBIx::DBSchema::DBD drivers (currently MySQL and PostgreSQL), import of column names and attributes *should* work for any database.

new_native DATABASE_HANDLE | DATA_SOURCE USERNAME PASSWORD [ ATTR ]

Creates a new DBIx::DBSchema object from an existing data source, which can be specified by passing an open DBI database handle, or by passing the DBI data source name, username and password. This uses database-native methods to read the schema, and will preserve any non-portable column types. The method is only available if there is a DBIx::DBSchema::DBD for the corresponding database engine (currently, MySQL and PostgreSQL).

load FILENAME

Loads a DBIx::DBSchema object from a file.

save FILENAME

Saves a DBIx::DBSchema object to a file.

addtable TABLE_OBJECT

Adds the given DBIx::DBSchema::Table object to this DBIx::DBSchema.

tables

Returns a list of the names of all tables.

table TABLENAME

Returns the specified DBIx::DBSchema::Table object.

sql [ DATABASE_HANDLE | DATA_SOURCE [ USERNAME PASSWORD [ ATTR ] ] ]

Returns a list of SQL `CREATE' statements for this schema.

The data source can be specified by passing an open DBI database handle, or by passing the DBI data source name, username and password.

Although the username and password are optional, it is best to call this method with a database handle or data source including a valid username and password - a DBI connection will be opened and the quoting and type mapping will be more reliable.

If passed a DBI data source (or handle) such as `DBI:mysql:database' or `DBI:Pg:dbname=database', will use syntax specific to that database engine. Currently supported databases are MySQL and PostgreSQL.

If not passed a data source (or handle), or if there is no driver for the specified database, will attempt to use generic SQL syntax.

pretty_print

Returns the data in this schema as Perl source, suitable for assigning to a hash.

pretty_read HASHREF

Creates a schema as specified by a data structure such as that created by pretty_print method.

AUTHOR

Ivan Kohler <ivan-dbix-dbschema@420.am>

Charles Shapiro <charles.shapiro@numethods.com> and Mitchell Friedman <mitchell.friedman@numethods.com> contributed the start of a Sybase driver.

COPYRIGHT

Copyright (c) 2000 Ivan Kohler Copyright (c) 2000 Mail Abuse Prevention System LLC All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

BUGS

Each DBIx::DBSchema object should have a name which corresponds to its name within the SQL database engine (DBI data source).

pretty_print is actually pretty ugly.

Perhaps pretty_read should eval column types so that we can use DBI qw(:sql_types) here instead of externally.