DBSchema(3pm)

💖 DBSchema — DBIx::DBSchema 💖

okay bestie, sit down, hydrate, and let me tell you about DBIx::DBSchema — the database-independent schema objects situation. it's a Perl thing, it's in the User Contributed Perl Documentation section, and honestly? it eats. 💅

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✨ 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;

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🌸 DESCRIPTION 🌸

so a DBIx::DBSchema object is literally just a collection of DBIx::DBSchema::Table objects, and together they represent a database schema. iconic behavior, no notes. 👑

This module implements an OO-interface to database schemas. Using this module, you can:

• create a database schema with an OO Perl interface ✨
• read the schema from an existing database 🦋
• save the schema to disk and restore it in a different process 💾
• write SQL CREATE statements statements for different databases from a single source 🌈
• 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 (they're giving "work in progress bestie"). DBIx::DBSchema will attempt to use generic SQL syntax for other databases. Assistance adding support for other databases is welcomed — fr fr, they want the help. See DBIx::DBSchema::DBD, "Driver Writer's Guide and Base Class".

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💅 METHODS 💅

• new TABLE_OBJECT, TABLE_OBJECT, ... — makes a brand new DBIx::DBSchema object. just pass it your table objects, periodt.
• new_odbc DATABASE_HANDLE | DATA_SOURCE USERNAME PASSWORD [ ATTR ] — creates a new DBIx::DBSchema object from an existing data source. you specify that source either by passing an open DBI database handle, or by passing the DBI data source name, username, and password. this one uses the experimental DBI type_info method to build a schema with standard (ODBC) SQL column types that most closely correspond to any non-portable column types. use this when you want to import a schema you're gonna use with a whole bunch of 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 you can specify by passing an open DBI database handle, or by passing the DBI data source name, username and password. this one uses database-native methods to read the schema, and it will preserve any non-portable column types. this method is only available if there's 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's an error, it returns false and drops an error message into $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. it's just vibing there for info.

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, which is also a DBIx::DBSchema object. (yes, "idential", the manpage said it, i'm just passing it along 💖)

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. dramatic, love that for us.

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.

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. and again, that connection is 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.

• update_schema [ OPTIONS_HASHREF, ] PROTOTYPE_SCHEMA, DATABASE_HANDLE | DATA_SOURCE [ USERNAME PASSWORD [ ATTR ] ] — same as sql_update_schema, except it actually runs the SQL commands to update the schema. Throws a fatal error if any statement fails. 😭 so like, be aware.
• 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 instead. Creates a schema as specified by a data structure such as that created by pretty_print method.

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👑 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.

(that last one says "contribued", and honestly? we're preserving the typo, it's part of the lore 💜)

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🫶 CONTRIBUTIONS 🫶

Contributions are welcome! I'm especially keen on any interest in the top items/projects below under BUGS. bestie they are literally asking, pls answer the call.

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🌈 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

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📜 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.

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💀 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.

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⭐ SEE ALSO ⭐

DBIx::DBSchema::Table, DBIx::DBSchema::Index, DBIx::DBSchema::Column, DBIx::DBSchema::DBD, DBIx::DBSchema::DBD::mysql, DBIx::DBSchema::DBD::Pg, FS::Record, DBI

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okay that's the whole thing, you're officially schema-pilled 🧚 this was DBIx::DBSchema as documented for perl v5.36.0, dated 2022-09-10, straight out of the DBSchema(3pm) page. go build something cute with it, mwah 💖🌸✨