Class: Amalgalite::TypeMaps::DefaultMap

Inherits:
Object
  • Object
show all
Defined in:
lib/amalgalite/type_maps/default_map.rb

Overview

An Amalgalite::TypeMap that does its best to convert between Ruby classes and known SQL data types.

Upon instantiation, DefaultMap generates a conversion map to try to figure out the best way to convert between populate SQL ‘types’ and ruby classes

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ DefaultMap

Returns a new instance of DefaultMap.



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# File 'lib/amalgalite/type_maps/default_map.rb', line 57

def initialize
end

Class Method Details

.methods_handling_sql_types ⇒ Object

:nodoc:



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# File 'lib/amalgalite/type_maps/default_map.rb', line 19

def methods_handling_sql_types # :nodoc:
  @methods_handling_sql_types ||= {
    'date'      => %w[ date ],
    'datetime'  => %w[ datetime ],
    'time'      => %w[ timestamp time ],
    'float'     => %w[ double float real numeric decimal ],
    'integer'   => %w[ integer tinyint smallint int int2 int4 int8 bigint serial bigserial ],
    'string'    => %w[ text char string varchar character json ],
    'boolean'   => %w[ bool boolean ],
    'blob'      => %w[ binary blob ],
  }
end

.sql_to_method(sql_type) ⇒ Object

say what method to call to convert an sql type to a ruby type



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# File 'lib/amalgalite/type_maps/default_map.rb', line 34

def sql_to_method( sql_type  ) # :nodoc:
  unless defined? @sql_to_method
    @sql_to_method = {}
    methods_handling_sql_types.each_pair do |method, sql_types|
      sql_types.each { |t| @sql_to_method[t] = method }
    end
  end
  return_method = @sql_to_method[sql_type]

  # the straight lookup didn't work, try iterating through the types and
  # see what is found
  unless return_method
    @sql_to_method.each_pair do |sql, method|
      if sql_type.index(sql) then
        return_method = method
        break
      end
    end
  end
  return return_method
end

Instance Method Details

#bind_type_of(obj) ⇒ Object

A straight logical mapping (for me at least) of basic Ruby classes to SQLite types, if nothing can be found then default to TEXT.



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# File 'lib/amalgalite/type_maps/default_map.rb', line 64

def bind_type_of( obj )
  case obj
  when Float
    ::Amalgalite::SQLite3::Constants::DataType::FLOAT
  when Integer
    ::Amalgalite::SQLite3::Constants::DataType::INTEGER
  when NilClass
    ::Amalgalite::SQLite3::Constants::DataType::NULL
  when ::Amalgalite::Blob
    ::Amalgalite::SQLite3::Constants::DataType::BLOB
  else
    ::Amalgalite::SQLite3::Constants::DataType::TEXT
  end
end

#blob(str) ⇒ Object

convert a string to a blob



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# File 'lib/amalgalite/type_maps/default_map.rb', line 162

def blob( str )
  ::Amalgalite::Blob.new( :string => str )
end

#boolean(str) ⇒ Object

convert a string to true of false



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# File 'lib/amalgalite/type_maps/default_map.rb', line 155

def boolean( str )
  ::Amalgalite::Boolean.to_bool( str )
end

#date(str) ⇒ Object

convert a string to a date



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# File 'lib/amalgalite/type_maps/default_map.rb', line 112

def date( str )
  Date.parse( str )
end

#datetime(str) ⇒ Object

convert a string to a datetime, if no timzone is found in the parsed string, set it to the local offset.



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# File 'lib/amalgalite/type_maps/default_map.rb', line 120

def datetime( str )
  DateTime.parse( str )
end

#float(str) ⇒ Object

convert a string to a Float



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# File 'lib/amalgalite/type_maps/default_map.rb', line 134

def float( str )
  Float( str )
end

#integer(str) ⇒ Object

convert an string to an Integer



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# File 'lib/amalgalite/type_maps/default_map.rb', line 141

def integer( str )
  Float( str ).to_i
end

#result_value_of(declared_type, value) ⇒ Object

Map the incoming value to an outgoing value. For some incoming values, there will be no change, but for some (i.e. Dates and Times) there is some conversion



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# File 'lib/amalgalite/type_maps/default_map.rb', line 84

def result_value_of( declared_type, value )
  case value
  when Numeric
    return value
  when NilClass
    return value
  when Amalgalite::Blob
    return value
  when String
    if declared_type then
      conversion_method = DefaultMap.sql_to_method( declared_type.downcase )
      if conversion_method then
        return send(conversion_method, value)  
      else
        raise ::Amalgalite::Error, "Unable to convert SQL type of #{declared_type} to a Ruby class"
      end
    else
      # unable to do any other conversion, just return what we have.
      return value
    end
  else 
    raise ::Amalgalite::Error, "Unable to convert a class #{value.class.name} with value #{value.inspect}"
  end
end

#string(str) ⇒ Object

convert a string to a String, yes redundant I know.



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# File 'lib/amalgalite/type_maps/default_map.rb', line 148

def string( str )
  str
end

#time(str) ⇒ Object

convert a string to a Time



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# File 'lib/amalgalite/type_maps/default_map.rb', line 127

def time( str )
  Time.parse( str )
end