Class: Mysql2postgres::PostgresFileWriter

Inherits:
PostgresWriter show all
Defined in:
lib/mysql2postgres/postgres_file_writer.rb

Direct Known Subclasses

PostgresDbWriter

Instance Attribute Summary

Attributes inherited from PostgresWriter

#destination, #filename

Instance Method Summary collapse

Methods inherited from PostgresWriter

#column_description, #column_type, #column_type_info, #process_row

Constructor Details

#initialize(file, destination) ⇒ PostgresFileWriter

Returns a new instance of PostgresFileWriter.



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 8

def initialize(file, destination)
  super()

  @filename = file
  @destination = destination

  @f = File.open file, 'w+:UTF-8'
  @f << <<~SQL_HEADER
    -- MySQL 2 PostgreSQL dump\n
    SET client_encoding = 'UTF8';
    SET standard_conforming_strings = off;
    SET check_function_bodies = false;
    SET client_min_messages = warning;

  SQL_HEADER
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 143

def close
  @f.close
end

#inload ⇒ Object 



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 147

def inload
  puts "\nSkip import to PostgreSQL DB. SQL file created successfully."
end

#truncate(table) ⇒ Object 



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 25

def truncate(table)
  serial_key = nil
  maxval = nil

  table.columns.map do |column|
    if column[:auto_increment]
      serial_key = column[:name]
      maxval = column[:maxval].to_i < 1 ? 1 : column[:maxval] + 1
    end
  end

  @f << <<~SQL_TRUNCATE
    -- TRUNCATE #{table.name};
    TRUNCATE #{PG::Connection.quote_ident table.name} CASCADE;

  SQL_TRUNCATE

  return unless serial_key

  @f << <<~SQL_SERIAL
    SELECT pg_catalog.setval(pg_get_serial_sequence('#{table.name}', '#{serial_key}'), #{maxval}, true);
  SQL_SERIAL
end

#write_constraints(table) ⇒ Object 



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 117

def write_constraints(table)
  table.foreign_keys.each do |key|
    @f << "ALTER TABLE #{PG::Connection.quote_ident table.name} " \
          "ADD FOREIGN KEY (#{quoted_list key[:column]}) " \
          "REFERENCES #{PG::Connection.quote_ident key[:ref_table]}(#{quoted_list key[:ref_column]}) " \
          "ON UPDATE #{key[:on_update]} ON DELETE #{key[:on_delete]};\n"
  end
end

#write_contents(table, reader) ⇒ Object 



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 126

def write_contents(table, reader)
  @f << <<~SQL_COPY
    --
    -- Data for Name: #{table.name}; Type: TABLE DATA; Schema: public
    --

    COPY "#{table.name}" (#{quoted_list(table.columns.map { |m| m[:name] })}) FROM stdin;
  SQL_COPY

  reader.paginated_read table, 1000 do |row, _counter|
    process_row table, row
    @f << row.join("\t")
    @f << "\n"
  end
  @f << "\\.\n\n"
end

#write_indexes(_table) ⇒ Object 



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 115

def write_indexes(_table); end

#write_table(table) ⇒ Object 



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# File 'lib/mysql2postgres/postgres_file_writer.rb', line 49

def write_table(table)
  primary_keys = []
  serial_key = nil
  maxval = nil

  columns = table.columns.map do |column|
    if column[:auto_increment]
      serial_key = column[:name]
      maxval = column[:maxval].to_i < 1 ? 1 : column[:maxval] + 1
    end
    primary_keys << column[:name] if column[:primary_key]
    "  #{column_description column}"
  end.join(",\n")

  if serial_key
    @f << <<~SQL_SEQUENCE
      --
      -- Name: #{table.name}_#{serial_key}_seq; Type: SEQUENCE; Schema: public
      --

      DROP SEQUENCE IF EXISTS #{table.name}_#{serial_key}_seq CASCADE;

      CREATE SEQUENCE #{table.name}_#{serial_key}_seq
          INCREMENT BY 1
          NO MAXVALUE
          NO MINVALUE
          CACHE 1;


      SELECT pg_catalog.setval('#{table.name}_#{serial_key}_seq', #{maxval}, true);

    SQL_SEQUENCE
  end

  @f << <<~SQL_TABLE
    -- Table: #{table.name}

    -- DROP TABLE #{table.name};
    DROP TABLE IF EXISTS #{PG::Connection.quote_ident table.name} CASCADE;

    CREATE TABLE #{PG::Connection.quote_ident table.name} (
  SQL_TABLE

  @f << columns

  if (primary_index = table.indexes.find { |index| index[:primary] })
    @f << ",\n  CONSTRAINT #{table.name}_pkey PRIMARY KEY(#{quoted_list primary_index[:columns]})"
  end

  @f << <<~SQL_OIDS
    \n)
    WITHOUT OIDS;
  SQL_OIDS

  table.indexes.each do |index|
    next if index[:primary]

    unique = index[:unique] ? 'UNIQUE ' : nil
    @f << <<~SQL_INDEX
      DROP INDEX IF EXISTS #{PG::Connection.quote_ident index[:name]} CASCADE;
      CREATE #{unique}INDEX #{PG::Connection.quote_ident index[:name]}
      ON #{PG::Connection.quote_ident table.name} (#{quoted_list index[:columns]});
    SQL_INDEX
  end
end