Ubuntu Manpage: DBIx::DBSchema - Database-independent schema objects

Provided by: libdbix-dbschema-perl_0.47-1_all

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" or die $DBIx::DBSchema::errstr;

         $schema->addtable($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 in a different process.  You can write SQL CREATE statements statements for
       different databases from a single source.  You can transform one schema to another, adding any necessary
       new columns, tables, indices and foreign keys.

       Currently supported databases are MySQL, PostgreSQL and SQLite.  Sybase and Oracle drivers are partially
       implemented.  DBIx::DBSchema will attempt to use generic SQL syntax for other databases.  Assistance
       adding support for other databases is welcomed.  See DBIx::DBSchema::DBD, "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. Note that this
method only uses "ODBC" column types; it does not require or use an ODBC driver.

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. If there is an error, returns false and puts an error
message in $DBIx::DBSchema::errstr;

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
used to check the database version as well as for more reliable quoting and type mapping. Note that
the database connection will be used passively, not to actually run the CREATE statements.

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.

sql_update_schema [ OPTIONS_HASHREF, ] PROTOTYPE_SCHEMA [ DATABASE_HANDLE | DATA_SOURCE [ USERNAME
PASSWORD [ ATTR ] ] ]
Returns a list of SQL statements to update this schema so that it is idential to the provided
prototype schema, also a DBIx::DBSchema object.

Right now this method knows how to add new tables and alter existing tables, including indices. If
specifically requested by passing an options hashref with drop_tables set true before all other
arguments, it will also drop tables.

See "sql_alter_table" in DBIx::DBSchema::Table, "sql_add_column" in DBIx::DBSchema::Column and
"sql_alter_column" in DBIx::DBSchema::Column for additional specifics and limitations.

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

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.

update_schema [ OPTIONS_HASHREF, ] PROTOTYPE_SCHEMA, DATABASE_HANDLE | DATA_SOURCE [ USERNAME PASSWORD [
ATTR ] ]
Same as sql_update_schema, except actually runs the SQL commands to update the schema. Throws a
fatal error if any statement fails.

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

pretty_read HASHREF
This method is not recommended. If you need to load and save your schema to a file, see the "load"
and "save" methods.

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

AUTHORS

       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.

       Daniel Hanks <hanksdc@about-inc.com> contributed the Oracle driver.

       Jesse Vincent contributed the SQLite driver and fixes to quiet down internal usage of the old API.

       Slaven Rezic <srezic@cpan.org> contributed column and table dropping, Pg bugfixes and more.

       Nathan Anderson <http://1id.com/=nathan.anderson> contribued updates to the SQLite and Sybase drivers.

CONTRIBUTIONS

       Contributions are welcome!  I'm especially keen on any interest in the  top  items/projects  below  under
       BUGS.

REPOSITORY

       The code is available from our public git repository:

         git clone git://git.freeside.biz/DBIx-DBSchema.git

       Or on the web:

         http://freeside.biz/gitweb/?p=DBIx-DBSchema.git
         Or:
         http://freeside.biz/gitlist/DBIx-DBSchema.git

COPYRIGHT

       Copyright  (c)  2000-2007  Ivan  Kohler Copyright (c) 2000 Mail Abuse Prevention System LLC Copyright (c)
       2007-2017 Freeside Internet Services, Inc.  All rights reserved.  This program is free software; you  can
       redistribute it and/or modify it under the same terms as Perl itself.

BUGS AND TODO

       Multiple primary keys are not yet supported.

       Foreign keys: need to support dropping, NOT VALID, reverse engineering w/mysql

       Need to port and test with additional databases

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

       Need to support "using" index attribute in pretty_read and in reverse engineering

       sql CREATE TABLE output should convert integers (i.e. use  DBI  qw(:sql_types);)  to  local  types  using
       DBI->type_info plus a hash to fudge things

   PRETTY_ BUGS
       pretty_print is actually pretty ugly.

       pretty_print  isn't  so  good  about  quoting  values...  save/load is a much better alternative to using
       pretty_print/pretty_read

       pretty_read is pretty ugly too.

       pretty_read should *not* create and pass in old-style unique/index indices when nothing is given  in  the
       read.

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

       perhaps we should just get rid of pretty_read  entirely.   pretty_print  is  useful  for  debugging,  but
       pretty_read is pretty bunk.