def create_sql(table,charset='UTF8')
      sql    = "CREATE TABLE #{table} ("
      fields = vectors.to_a.collect do |f|
        v = self[f]
        f.to_s + ' ' + v.db_type
      end

      sql + fields.join(",\n ")+") CHARACTER SET=#{charset};"
    end
def create_sql(table,charset='UTF8')
      sql    = "CREATE TABLE #{table} ("
      fields = vectors.to_a.collect do |f|
        v = self[f]
        f.to_s + ' ' + v.db_type
      end

      sql + fields.join(",\n ")+") CHARACTER SET=#{charset};"
    end
Create a sql, basen on a given Dataset

 == Arguments

 * table - String specifying name of the table that will created in SQL.
 * charset - Character set. Default is "UTF8".

 @example

  ds = Daru::DataFrame.new({
   :id   => Daru::Vector.new([1,2,3,4,5]),
   :name => Daru::Vector.new(%w{Alex Peter Susan Mary John})
  })
  ds.create_sql('names')
   #=>"CREATE TABLE names (id INTEGER,\n name VARCHAR (255)) CHARACTER SET=UTF8;"