Module: DynamicMigrations::ActiveRecord::Migrators::ForeignKeyConstraint

Included in:
DynamicMigrations::ActiveRecord::Migrators
Defined in:
lib/dynamic_migrations/active_record/migrators/foreign_key_constraint.rb

Defined Under Namespace

Classes: ForeignKeyOnDeleteOptionsError, UnexpectedReferentialActionError

Instance Method Summary collapse

Instance Method Details

#add_foreign_key(table_name, column_names, foreign_table_name, foreign_column_names, name:, foreign_schema: nil, initially_deferred: false, deferrable: false, on_delete: :no_action, on_update: :no_action, comment: nil) ⇒ Object

because rails migrations don’t support composite (multiple column) foreign keys column_names and foreign_column_names can be a single column name or an array of column names



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# File 'lib/dynamic_migrations/active_record/migrators/foreign_key_constraint.rb', line 14

def add_foreign_key table_name, column_names, foreign_table_name, foreign_column_names, name:, foreign_schema: nil, initially_deferred: false, deferrable: false, on_delete: :no_action, on_update: :no_action, comment: nil
  if initially_deferred == true && deferrable == false
    raise DeferrableOptionsError, "A constraint can only be initially deferred if it is also deferrable"
  end

  # convert single column names into arrays, this simplifies the logic below
  column_names = column_names.is_a?(Array) ? column_names : [column_names]
  foreign_column_names = foreign_column_names.is_a?(Array) ? foreign_column_names : [foreign_column_names]
  # default to the current schema
  foreign_schema_name = foreign_schema.nil? ? schema_name : foreign_schema

  # allow it to be deferred, and defer it by default
  deferrable_sql = if initially_deferred
    "DEFERRABLE INITIALLY DEFERRED"

  # allow it to be deferred, but do not deferr by default
  elsif deferrable
    "DEFERRABLE INITIALLY IMMEDIATE"

  # it can not be deferred (this is the default)
  else
    "NOT DEFERRABLE"
  end

  execute <<~SQL
    ALTER TABLE #{table_name}
      ADD CONSTRAINT #{name}
        FOREIGN KEY (#{column_names.join(", ")})
          REFERENCES  #{foreign_schema_name}.#{foreign_table_name} (#{foreign_column_names.join(", ")})
      ON DELETE #{referential_action_to_sql on_delete}
      ON UPDATE #{referential_action_to_sql on_update}
      #{deferrable_sql};
  SQL

  if comment.is_a? String
    set_foreign_key_comment table_name, name, comment
  end
end

#remove_foreign_key(table_name, name) ⇒ Object 



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# File 'lib/dynamic_migrations/active_record/migrators/foreign_key_constraint.rb', line 53

def remove_foreign_key table_name, name
  execute <<~SQL
    ALTER TABLE #{table_name}
      DROP CONSTRAINT #{name};
  SQL
end

#remove_foreign_key_comment(table_name, foreign_key_name) ⇒ Object

remove a foreign_key comment



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# File 'lib/dynamic_migrations/active_record/migrators/foreign_key_constraint.rb', line 68

def remove_foreign_key_comment table_name, foreign_key_name
  execute <<~SQL
    COMMENT ON CONSTRAINT #{foreign_key_name} ON #{schema_name}.#{table_name} IS NULL;
  SQL
end

#set_foreign_key_comment(table_name, foreign_key_name, comment) ⇒ Object

add a comment to the foreign_key



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# File 'lib/dynamic_migrations/active_record/migrators/foreign_key_constraint.rb', line 61

def set_foreign_key_comment table_name, foreign_key_name, comment
  execute <<~SQL
    COMMENT ON CONSTRAINT #{foreign_key_name} ON #{schema_name}.#{table_name} IS #{quote comment};
  SQL
end