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Contents
# -*- ruby -*-
# frozen_string_literal: true
require 'pg' unless defined?( PG )
# Simple set of rules for type casting common PostgreSQL types from Ruby
# 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 PG::BasicTypeMapBasedOnResult.new .
#
# This class works equal to PG::BasicTypeMapForResults, but does not define decoders for
# the given result OIDs, but encoders. So it can be used to type cast field values based on
# the type OID retrieved by a separate SQL query.
#
# PG::TypeMapByOid#build_column_map(result) can be used to generate a result independent
# PG::TypeMapByColumn type map, which can subsequently be used to cast query bind parameters
# or #put_copy_data fields.
#
# Example:
# conn.exec( "CREATE TEMP TABLE copytable (t TEXT, i INT, ai INT[])" )
#
# # Retrieve table OIDs per empty result set.
# res = conn.exec( "SELECT * FROM copytable LIMIT 0" )
# # Build a type map for common ruby to database type encoders.
# btm = PG::BasicTypeMapBasedOnResult.new(conn)
# # Build a PG::TypeMapByColumn with encoders suitable for copytable.
# tm = btm.build_column_map( res )
# row_encoder = PG::TextEncoder::CopyRow.new type_map: tm
#
# conn.copy_data( "COPY copytable FROM STDIN", row_encoder ) do |res|
# conn.put_copy_data ['a', 123, [5,4,3]]
# end
# This inserts a single row into copytable with type casts from ruby to
# database types.
class PG::BasicTypeMapBasedOnResult < PG::TypeMapByOid
include PG::BasicTypeRegistry::Checker
def initialize(connection_or_coder_maps, registry: nil)
@coder_maps = build_coder_maps(connection_or_coder_maps, registry: registry)
# Populate TypeMapByOid hash with encoders
@coder_maps.each_format(:encoder).flat_map{|f| f.coders }.each do |coder|
add_coder(coder)
end
end
end
Version data entries
76 entries across 76 versions & 4 rubygems