A library for generating an ActiveRecord model from an existing database table.

Currently supports both Oracle and SQL Server databases.

This will install a "dmg" (Database Model Generator) executable that you can use from the command line.

Originally called "oracle-model-generator" and put into the dust bin, I've decided to revive this library with the help of AI. Specifically, I've added SQLServer support, and plan to add Postgres support.

I also plan on lots of improvements, and some general refactoring.

Using the command line tool:

dmg -T oracle -d your_database -t locations -u some_user -p some_password

dmg -T sqlserver -s localhost -d your_database -t locations -u sa -p your_password

dmg -d your_database -t locations -u some_user -p some_password

dmg -s localhost -d your_database -t locations -u sa -p password

The above command results in a file called "location.rb". This is an ActiveRecord model declaration, with all validations, primary keys, table name and belongs_to relationships defined.

If your LOCATIONS table looks like this:

create table locations(
  location_id number(4,0) primary key,
  street_address varchar2(40),
  postal_code varchar2(12),
  city varchar2(30) not null
  state_province varchar2(25),
  country_id CHAR(2),
  constraint "LOC_C_ID_FK" FOREIGN KEY (country_id)
    references COUNTRIES (country_id)
)

The dmg library will generate this:

class Location < ActiveRecord::Base
  set_table_name :locations
  set_primary_key :location_id

  # Table relationships

  belongs_to :countries

  # Validations

  validates :location_id, :presence => true, :numericality => {
    :less_than_or_equal_to => 9999,
    :greater_than_or_equal_to => -9999,
    :only_integer => true
  }

  validates :street_address, :length => {:maximum => 40}
  validates :postal_code, :length => {:maximum => 12}
  validates :city, :length => {:maximum => 30}, :presence => true
  validates :state_province, :length => {:maximum => 25}
  validates :country_id, :length => {:maximum => 2}
end

It will also generate a corresponding test file using test-unit 2 by default. For the above example you will see some tests like this:

class TC_Location < Test::Unit::TestCase
  def setup
    @location = Location.new
  end

  test 'table name is locations' do
    assert_equal('locations', Location.table_name)
  end

  test 'primary key is location_id' do
    assert_equal('location_id', Location.primary_key)
  end

  test 'location_id basic functionality' do
    assert_respond_to(@location, :location_id)
    assert_nothing_raised{ @location.location_id }
    assert_kind_of(Numeric, @location.location_id)
  end

  test 'location_id must be a number' do
    @location.location_id = 'test_string'
    assert_false(@location.valid?)
    assert_true(@location.errors[:location_id].include?('is not a number'))
  end

  test 'location_id cannot exceed the value 9999' do
    @location.location_id = 10000
    assert_false(@location.valid?)
    assert_true(@location.errors[:location_id].include?('must be less than or equal to 9999'))
  end

  # ... and so on.
end

• getopt
• One of the following gems, depending on which vendor you're using.

• ruby-oci8

• tiny_tds

Run cd docker/oracle && docker-compose run --rm oracle-model-generator bundle exec rspec.

You may need to use sudo. No guarantees on MacOS because of known issues with database client libraries.

Run cd docker/sqlserver && ./test.sh to start SQL Server, then run tests.

Again, no guarantees on MacOS.

If you want to be able to avoid specifying a username and password on the command line then you will need the dbi-dbrc library.

If you want your models to support multiple primary keys, then you will need to install the composite_primary_keys library.

If you want date format validations, then you will need to install the validates_timeliness library.

• Oracle: Full support via ruby-oci8
• SQL Server: Full support via tiny_tds
• Auto-detection: Automatically detects database type based on connection parameters

Originally focused only on Oracle, this library has been expanded to support SQL Server as well. The architecture now supports multiple database vendors, and I will probably add Postgres support in the future.

• Multi-database support: Oracle and SQL Server
• Auto-detection: Automatically detects database type
• Index recommendations: Suggests optimal indexes for your tables
• Multiple test frameworks: Supports test-unit, minitest, and rspec
• Docker support: Complete Docker environments for testing both databases

• Add support for views.

Thanks go to Daniel Luna for his --class patch.

None known. If you find any issues, please report them on the github project page at http://www.github.com/djberg96/database-model-generator.

This package is provided "as is" and without any express or implied warranties, including, without limitation, the implied warranties of merchantability and fitness for a particular purpose.

(C) 2010-2025 Daniel J. Berger All Rights Reserved

Apache-2.0

Daniel J. Berger