class PG::BasicTypeMapForQueries

Simple set of rules for type casting common Ruby types to PostgreSQL.

OIDs of supported type casts are not hard-coded in the sources, but are retrieved from the PostgreSQL's pg_type table in ::new .

Query params are type casted based on the class of the given value.

Higher level libraries will most likely not make use of this class, but use their own derivation of PG::TypeMapByClass or another set of rules to choose suitable encoders and decoders for the values to be sent.

Example:

conn = PG::Connection.new
# Assign a default ruleset for type casts of input and output values.
conn.type_map_for_queries = PG::BasicTypeMapForQueries.new(conn)
# Execute a query. The Integer param value is typecasted internally by PG::BinaryEncoder::Int8.
# The format of the parameter is set to 1 (binary) and the OID of this parameter is set to 20 (int8).
res = conn.exec_params( "SELECT $1", [5] )

Constants

DEFAULT_ARRAY_TYPE_MAP
DEFAULT_TYPE_MAP

Public Class Methods

new(connection) click to toggle source
# File lib/pg/basic_type_mapping.rb, line 359
def initialize(connection)
        @coder_maps = build_coder_maps(connection)

        populate_encoder_list
        @array_encoders_by_klass = array_encoders_by_klass
        @anyarray_encoder = coder_by_name(0, :encoder, '_any')
end

Private Instance Methods

array_encoders_by_klass() click to toggle source
# File lib/pg/basic_type_mapping.rb, line 391
def array_encoders_by_klass
        DEFAULT_ARRAY_TYPE_MAP.inject({}) do |h, (klass, (format, name))|
                h[klass] = coder_by_name(format, :encoder, name)
                h
        end
end
coder_by_name(format, direction, name) click to toggle source
# File lib/pg/basic_type_mapping.rb, line 369
def coder_by_name(format, direction, name)
        check_format_and_direction(format, direction)
        @coder_maps[format][direction].coder_by_name(name)
end
get_array_type(value) click to toggle source
# File lib/pg/basic_type_mapping.rb, line 398
def get_array_type(value)
        elem = value
        while elem.kind_of?(Array)
                elem = elem.first
        end
        @array_encoders_by_klass[elem.class] ||
                        elem.class.ancestors.lazy.map{|ancestor| @array_encoders_by_klass[ancestor] }.find{|a| a } ||
                        @anyarray_encoder
end
populate_encoder_list() click to toggle source
# File lib/pg/basic_type_mapping.rb, line 374
def populate_encoder_list
        DEFAULT_TYPE_MAP.each do |klass, selector|
                if Array === selector
                        format, name, oid_name = selector
                        coder = coder_by_name(format, :encoder, name).dup
                        if oid_name
                                coder.oid = coder_by_name(format, :encoder, oid_name).oid
                        else
                                coder.oid = 0
                        end
                        self[klass] = coder
                else
                        self[klass] = selector
                end
        end
end