Class: Abtab::Driver::DbiDriver

Inherits:
Abtab::Driver show all
Defined in:
lib/abtab/drivers/dbi_driver.rb

Constant Summary collapse

CREDENTIALS_RC_FILE = 
"#{ENV['HOME']}/.abtab.dbrc"
DB_MODULES = 
{
  'Pg'      => { :require => 'Pg', :name => 'Pg' },
  'pg'      => { :require => 'pg', :name => 'Pg' },
  # TODO: test these
  #'mysql'   => 'mysql',
  #'Mysql'   => 'mysql',
  #'sqlite'  => 'sqlite3',
  #'SQLite'  => 'sqlite3',
  #'sqlite3' => 'sqlite3',
  #'SQLite3' => 'sqlite3',
}

Instance Method Summary collapse

Methods inherited from Abtab::Driver

#import, #url_parse

Constructor Details

#initialize(url) ⇒ DbiDriver

Returns a new instance of DbiDriver.



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# File 'lib/abtab/drivers/dbi_driver.rb', line 29

def initialize url
  @options = {
    :dbi_driver => nil,
    :host       => nil,
    :user       => nil,
    :pass       => nil,
    :database   => nil,
    :table      => nil,
  }

  @rc_defaults = {}
  if File.exist? CREDENTIALS_RC_FILE
    @rc_defaults.merge!(YAML.load_file(CREDENTIALS_RC_FILE))
  end

  @url = url
  schema, rest = url.split '://', 2

  # expect 'driver' name, eg: pg
  driver, host, database_name, table = rest.split '/', 4

  if driver =~ /@/
    user_pass, driver = driver.split '@', 2
    user, pass = nil, nil
    if user_pass =~ /:/
      user, pass = user_pass.split ':', 2
      @options[:user] = user
      @options[:pass] = pass
    end
    @options[:dbi_driver] = driver
  end

  @options[:dbi_driver] = driver
  @options[:database]   = database_name
  @options[:host]       = host
  @options[:table]      = table

  @options[:user] ||= lookup_rc_default @options[:host], @options[:database], "user"
  @options[:pass] ||= lookup_rc_default @options[:host], @options[:database], "pass"

  #puts "OPTIONS: #{@options.inspect}"

  require DB_MODULES[@options[:dbi_driver]][:require]
  driver_name = DB_MODULES[@options[:dbi_driver]][:name]

  @conn = DBI.connect("DBI:#{driver_name}:database=#{@options[:database]};host=#{@options[:host]}",@options[:user],@options[:pass]);

end

Instance Method Details

#close ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 128

def close 
  close_statement_handle
  close_connection
end

#close_connection ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 133

def close_connection
  if @conn
    @conn.close if @conn.respond_to? :close
    @conn = nil
  end
end

#close_statement_handle ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 140

def close_statement_handle
  if @statement_handle
    @statement_handle.finish
    @statement_handle = nil
  end
end

#columns ⇒ Object

def open_for_writing

  close_statement_handle
  @columns = get_col_names @options[:table]
  sql_stmt = sprintf("INSERT INTO #{@options[:table]} VALUES (%s)", get_col_names.map {'?'}.join(","))
  puts "sql_stmt: #{sql_stmt}"
  @statement_handle = @conn.prepare sql_stmt
end



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# File 'lib/abtab/drivers/dbi_driver.rb', line 98

def columns
  @columns
end

#get_col_names(table) ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 102

def get_col_names table
  sth = @conn.prepare "SELECT * FROM #{table} where 1=0"
  sth.execute
  col_names = sth.column_names
  sth.finish
  col_names
end

#lookup_rc_default(*keys) ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 19

def lookup_rc_default *keys
  #puts "LOOKUP: #{keys.inspect}"
  m = @rc_defaults
  keys.each do |k|
    #puts "  k=#{k} m=#{m.inspect}"
    m = m[k] if m
  end
  m
end

#next_record ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 110

def next_record
  return @statement_handle.fetch if @statement_handle
  if @rows && !@rows.empty?
    table = @rows.shift
    sth = @conn.prepare("SELECT COUNT('x') from #{table}")
    sth.execute
    count = sth.fetch_array.first
    sth.finish
    return [table,count]
  end
  return nil
end

#open_for_reading ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 78

def open_for_reading
  if @options[:table]
    @columns = get_col_names @options[:table]
    @statement_handle = @conn.prepare "select * from #{@options[:table]}"
    @statement_handle.execute
  else
    @columns = ['NAME','ROWS']
    @rows = @conn.tables
  end
end

#rewind ⇒ Object 



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# File 'lib/abtab/drivers/dbi_driver.rb', line 123

def rewind
  close_connection
  open_for_reading
end