Class: Baza::Dump

Inherits:
Object
  • Object
show all
Defined in:
lib/baza/dump.rb

Overview

This class can be used to make SQL-dumps of databases, tables or however you want it.

Instance Method Summary collapse

Constructor Details

#initialize(args) ⇒ Dump

Constructor.

Examples

dump = Baza::Dump.new(:db => db)



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# File 'lib/baza/dump.rb', line 6

def initialize(args)
  @db = args.fetch(:db)
  @debug = args[:debug]
  @tables = args[:tables]
end

Instance Method Details

#debug(message) ⇒ Object 



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# File 'lib/baza/dump.rb', line 64

def debug(message)
  puts message if @debug
end

#dump(io) ⇒ Object

Dumps all tables into the given IO.



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# File 'lib/baza/dump.rb', line 23

def dump(io)
  debug "Going through tables."
  @rows_count = 0

  if @tables
    tables = @tables
  else
    tables = @db.tables.list
  end

  if @on_status
    @on_status.call(text: "Preparing.")

    @rows_count_total = 0
    tables.each do |table_obj|
      @rows_count_total += table_obj.rows_count
    end
  end

  tables.each do |table_obj|
    table_obj = @db.tables[table_obj] if table_obj.is_a?(String) || table_obj.is_a?(Symbol)
    next if table_obj.native?

    # Figure out keys.
    @keys = []
    table_obj.columns do |col|
      @keys << col.name
    end

    @table_obj = table_obj
    update_status
    debug "Dumping table: '#{table_obj.name}'."
    dump_table(io, table_obj)
  end
end

#dump_insert_multi(io, table_obj, rows) ⇒ Object

Dumps the given rows from the given table into the given IO.



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# File 'lib/baza/dump.rb', line 112

def dump_insert_multi(io, table_obj, rows)
  debug "Inserting #{rows.length} into #{table_obj.name}."
  sqls = @db.insert_multi(table_obj.name, rows, return_sql: true, keys: @keys)
  sqls.each do |sql|
    io.write("#{sql};\n")
  end

  rows.clear

  # Ensure garbage collection or we might start using A LOT of memory.
  GC.start
end

#dump_table(io, table_obj) ⇒ Object

Dumps the given table into the given IO.



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# File 'lib/baza/dump.rb', line 69

def dump_table(io, table_obj)
  create_data = table_obj.data
  create_data.delete(:name)

  # Get SQL for creating table and add it to IO.
  sqls = @db.tables.create(table_obj.name, create_data, return_sql: true)
  sqls.each do |sql|
    io.write("#{sql};\n")
  end


  # Try to find a primary column in the table.
  prim_col = nil
  table_obj.columns do |col|
    if col.primarykey?
      prim_col = col
      break
    end
  end


  debug "Dumping data for table: #{table_obj.name}"

  # Set up rows and way to fill rows.
  rows = []


  @db.select(table_obj.name, nil, unbuffered: true) do |row|
    rows << row.values
    @rows_count += 1

    if rows.length >= 1000
      update_status
      dump_insert_multi(io, table_obj, rows)
    end
  end


  # Dump the last rows if any.
  dump_insert_multi(io, table_obj, rows) unless rows.empty?
end

#on_status(&block) ⇒ Object

A block can be executed when a new status occurs.



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# File 'lib/baza/dump.rb', line 60

def on_status(&block)
  @on_status = block
end

#update_status ⇒ Object

Method used to update the status.



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# File 'lib/baza/dump.rb', line 13

def update_status
  return nil unless @on_status
  rows_count = Knj::Locales.number_out(@rows_count, 0)
  rows_count_total = Knj::Locales.number_out(@rows_count_total, 0)
  percent = (@rows_count.to_f / @rows_count_total.to_f) * 100
  percent_text = Knj::Locales.number_out(percent, 1)
  @on_status.call(text: "Dumping table: '#{@table_obj.name}' (#{rows_count}/#{rows_count_total} - #{percent_text}%).")
end