表のツリーを書く

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追記
一応、動いた。管理者で動かしたら、動かないかも…

#!/usr/bin/env ruby

require "dbi"
class Table

  attr_reader :name, :parent, :children
  def initialize(name=nil)

    @name = name

    @children = 

  end
  def set_parent(parent)

    @parent = parent

    parent.add_child(self)

  end
  def add_child(child)

    @children << child

  end
  def to_s(tabs=, branch="", strbuf="")

    put_row(@name, tabs, branch, strbuf)

    @children.each_with_index {|child, i|

      last = (i+1 >= @children.size)

      tabs.push(last ? "　" : "│")

      branch = last ? "└" : "├"

      child.to_s(tabs, branch, strbuf)

      tabs.pop

    }

    return strbuf

  end
  private

  def put_row(name, tabs, branch, strbuf)

    head = tabs.clone

    head.pop unless head.empty?

    head << branch

    strbuf << head.join + name + "\n"

  end

end
class FKTree

  def initialize

    @root = Table.new("/")

    @tables = {"/"=>@root}

  end
  def add(r_table, table)

    parent = r_table ? get_table(r_table) : @root

    child = get_table(table)

    parent.add_child(child)

  end
  def to_s

    return @root.to_s

  end
  private

  def get_table(name)

    return @tables[name] if @tables.has_key?(name)

    table = Table.new(name)

    @tables[name] = table

    return table

  end

end
sql =<<EOS

SELECT A.TABLE_NAME, C.TABLE_NAME R_TABLE_NAME

FROM  USER_TABLES  A, USER_CONSTRAINTS B, USER_CONSTRAINTS C

WHERE A.TABLE_NAME = B.TABLE_NAME(+)

AND B.CONSTRAINT_TYPE(+)  ='R'

AND B.R_CONSTRAINT_NAME = C.CONSTRAINT_NAME(+)

EOS
fktree = FKTree.new
DBI.connect("DBI:OCI8:oracle", "scott", "tiger") {|dbh|

  dbh.select_all(sql) {|row|

    fktree.add(row["R_TABLE_NAME"], row["TABLE_NAME"])

  }

}
puts fktree