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require 'active_record/connection_adapters/abstract_adapter'
begin
require_library_or_gem 'pg'
rescue LoadError => e
begin
require_library_or_gem 'postgres'
class PGresult
alias_method :nfields, :num_fields unless self.method_defined?(:nfields)
alias_method :ntuples, :num_tuples unless self.method_defined?(:ntuples)
alias_method :ftype, :type unless self.method_defined?(:ftype)
alias_method :cmd_tuples, :cmdtuples unless self.method_defined?(:cmd_tuples)
end
rescue LoadError
raise e
end
end
module ActiveRecord
class Base
# Establishes a connection to the database that's used by all Active Record objects
def self.postgresql_connection(config) # :nodoc:
config = config.symbolize_keys
host = config[:host]
port = config[:port] || 5432
username = config[:username].to_s
password = config[:password].to_s
if config.has_key?(:database)
database = config[:database]
else
raise ArgumentError, "No database specified. Missing argument: database."
end
# The postgres drivers don't allow the creation of an unconnected PGconn object,
# so just pass a nil connection object for the time being.
ConnectionAdapters::PostgreSQLAdapter.new(nil, logger, [host, port, nil, nil, database, username, password], config)
end
end
module ConnectionAdapters
# PostgreSQL-specific extensions to column definitions in a table.
class PostgreSQLColumn < Column #:nodoc:
# Instantiates a new PostgreSQL column definition in a table.
def initialize(name, default, sql_type = nil, null = true)
super(name, self.class.extract_value_from_default(default), sql_type, null)
end
private
# Extracts the scale from PostgreSQL-specific data types.
def extract_scale(sql_type)
# Money type has a fixed scale of 2.
sql_type =~ /^money/ ? 2 : super
end
# Extracts the precision from PostgreSQL-specific data types.
def extract_precision(sql_type)
# Actual code is defined dynamically in PostgreSQLAdapter.connect
# depending on the server specifics
super
end
# Escapes binary strings for bytea input to the database.
def self.string_to_binary(value)
if PGconn.respond_to?(:escape_bytea)
self.class.module_eval do
define_method(:string_to_binary) do |value|
PGconn.escape_bytea(value) if value
end
end
else
self.class.module_eval do
define_method(:string_to_binary) do |value|
if value
result = ''
value.each_byte { |c| result << sprintf('\\\\%03o', c) }
result
end
end
end
end
self.class.string_to_binary(value)
end
# Unescapes bytea output from a database to the binary string it represents.
def self.binary_to_string(value)
# In each case, check if the value actually is escaped PostgreSQL bytea output
# or an unescaped Active Record attribute that was just written.
if PGconn.respond_to?(:unescape_bytea)
self.class.module_eval do
define_method(:binary_to_string) do |value|
if value =~ /\\\d{3}/
PGconn.unescape_bytea(value)
else
value
end
end
end
else
self.class.module_eval do
define_method(:binary_to_string) do |value|
if value =~ /\\\d{3}/
result = ''
i, max = 0, value.size
while i < max
char = value[i]
if char == ?\\
if value[i+1] == ?\\
char = ?\\
i += 1
else
char = value[i+1..i+3].oct
i += 3
end
end
result << char
i += 1
end
result
else
value
end
end
end
end
self.class.binary_to_string(value)
end
# Maps PostgreSQL-specific data types to logical Rails types.
def simplified_type(field_type)
case field_type
# Numeric and monetary types
when /^(?:real|double precision)$/
:float
# Monetary types
when /^money$/
:decimal
# Character types
when /^(?:character varying|bpchar)(?:\(\d+\))?$/
:string
# Binary data types
when /^bytea$/
:binary
# Date/time types
when /^timestamp with(?:out)? time zone$/
:datetime
when /^interval$/
:string
# Geometric types
when /^(?:point|line|lseg|box|"?path"?|polygon|circle)$/
:string
# Network address types
when /^(?:cidr|inet|macaddr)$/
:string
# Bit strings
when /^bit(?: varying)?(?:\(\d+\))?$/
:string
# XML type
when /^xml$/
:string
# Arrays
when /^\D+\[\]$/
:string
# Object identifier types
when /^oid$/
:integer
# Pass through all types that are not specific to PostgreSQL.
else
super
end
end
# Extracts the value from a PostgreSQL column default definition.
def self.extract_value_from_default(default)
case default
# Numeric types
when /\A-?\d+(\.\d*)?\z/
default
# Character types
when /\A'(.*)'::(?:character varying|bpchar|text)\z/m
$1
# Character types (8.1 formatting)
when /\AE'(.*)'::(?:character varying|bpchar|text)\z/m
$1.gsub(/\\(\d\d\d)/) { $1.oct.chr }
# Binary data types
when /\A'(.*)'::bytea\z/m
$1
# Date/time types
when /\A'(.+)'::(?:time(?:stamp)? with(?:out)? time zone|date)\z/
$1
when /\A'(.*)'::interval\z/
$1
# Boolean type
when 'true'
true
when 'false'
false
# Geometric types
when /\A'(.*)'::(?:point|line|lseg|box|"?path"?|polygon|circle)\z/
$1
# Network address types
when /\A'(.*)'::(?:cidr|inet|macaddr)\z/
$1
# Bit string types
when /\AB'(.*)'::"?bit(?: varying)?"?\z/
$1
# XML type
when /\A'(.*)'::xml\z/m
$1
# Arrays
when /\A'(.*)'::"?\D+"?\[\]\z/
$1
# Object identifier types
when /\A-?\d+\z/
$1
else
# Anything else is blank, some user type, or some function
# and we can't know the value of that, so return nil.
nil
end
end
end
end
module ConnectionAdapters
# The PostgreSQL adapter works both with the native C (http://ruby.scripting.ca/postgres/) and the pure
# Ruby (available both as gem and from http://rubyforge.org/frs/?group_id=234&release_id=1944) drivers.
#
# Options:
#
# * <tt>:host</tt> - Defaults to "localhost".
# * <tt>:port</tt> - Defaults to 5432.
# * <tt>:username</tt> - Defaults to nothing.
# * <tt>:password</tt> - Defaults to nothing.
# * <tt>:database</tt> - The name of the database. No default, must be provided.
# * <tt>:schema_search_path</tt> - An optional schema search path for the connection given as a string of comma-separated schema names. This is backward-compatible with the <tt>:schema_order</tt> option.
# * <tt>:encoding</tt> - An optional client encoding that is used in a <tt>SET client_encoding TO <encoding></tt> call on the connection.
# * <tt>:min_messages</tt> - An optional client min messages that is used in a <tt>SET client_min_messages TO <min_messages></tt> call on the connection.
# * <tt>:allow_concurrency</tt> - If true, use async query methods so Ruby threads don't deadlock; otherwise, use blocking query methods.
class PostgreSQLAdapter < AbstractAdapter
# Returns 'PostgreSQL' as adapter name for identification purposes.
def adapter_name
'PostgreSQL'
end
# Initializes and connects a PostgreSQL adapter.
def initialize(connection, logger, connection_parameters, config)
super(connection, logger)
@connection_parameters, @config = connection_parameters, config
connect
end
# Is this connection alive and ready for queries?
def active?
if @connection.respond_to?(:status)
@connection.status == PGconn::CONNECTION_OK
else
# We're asking the driver, not ActiveRecord, so use @connection.query instead of #query
@connection.query 'SELECT 1'
true
end
# postgres-pr raises a NoMethodError when querying if no connection is available.
rescue PGError, NoMethodError
false
end
# Close then reopen the connection.
def reconnect!
if @connection.respond_to?(:reset)
@connection.reset
configure_connection
else
disconnect!
connect
end
end
# Close the connection.
def disconnect!
@connection.close rescue nil
end
def native_database_types #:nodoc:
{
:primary_key => "serial primary key",
:string => { :name => "character varying", :limit => 255 },
:text => { :name => "text" },
:integer => { :name => "integer" },
:float => { :name => "float" },
:decimal => { :name => "decimal" },
:datetime => { :name => "timestamp" },
:timestamp => { :name => "timestamp" },
:time => { :name => "time" },
:date => { :name => "date" },
:binary => { :name => "bytea" },
:boolean => { :name => "boolean" }
}
end
# Does PostgreSQL support migrations?
def supports_migrations?
true
end
# Does PostgreSQL support standard conforming strings?
def supports_standard_conforming_strings?
# Temporarily set the client message level above error to prevent unintentional
# error messages in the logs when working on a PostgreSQL database server that
# does not support standard conforming strings.
client_min_messages_old = client_min_messages
self.client_min_messages = 'panic'
# postgres-pr does not raise an exception when client_min_messages is set higher
# than error and "SHOW standard_conforming_strings" fails, but returns an empty
# PGresult instead.
has_support = query('SHOW standard_conforming_strings')[0][0] rescue false
self.client_min_messages = client_min_messages_old
has_support
end
# Returns the configured supported identifier length supported by PostgreSQL,
# or report the default of 63 on PostgreSQL 7.x.
def table_alias_length
@table_alias_length ||= (postgresql_version >= 80000 ? query('SHOW max_identifier_length')[0][0].to_i : 63)
end
# QUOTING ==================================================
# Quotes PostgreSQL-specific data types for SQL input.
def quote(value, column = nil) #:nodoc:
if value.kind_of?(String) && column && column.type == :binary
"#{quoted_string_prefix}'#{column.class.string_to_binary(value)}'"
elsif value.kind_of?(String) && column && column.sql_type =~ /^xml$/
"xml '#{quote_string(value)}'"
elsif value.kind_of?(Numeric) && column && column.sql_type =~ /^money$/
# Not truly string input, so doesn't require (or allow) escape string syntax.
"'#{value.to_s}'"
elsif value.kind_of?(String) && column && column.sql_type =~ /^bit/
case value
when /^[01]*$/
"B'#{value}'" # Bit-string notation
when /^[0-9A-F]*$/i
"X'#{value}'" # Hexadecimal notation
end
else
super
end
end
# Quotes strings for use in SQL input in the postgres driver for better performance.
def quote_string(s) #:nodoc:
if PGconn.respond_to?(:escape)
self.class.instance_eval do
define_method(:quote_string) do |s|
PGconn.escape(s)
end
end
else
# There are some incorrectly compiled postgres drivers out there
# that don't define PGconn.escape.
self.class.instance_eval do
undef_method(:quote_string)
end
end
quote_string(s)
end
# Quotes column names for use in SQL queries.
def quote_column_name(name) #:nodoc:
%("#{name}")
end
# Quote date/time values for use in SQL input. Includes microseconds
# if the value is a Time responding to usec.
def quoted_date(value) #:nodoc:
if value.acts_like?(:time) && value.respond_to?(:usec)
"#{super}.#{sprintf("%06d", value.usec)}"
else
super
end
end
# REFERENTIAL INTEGRITY ====================================
def supports_disable_referential_integrity?() #:nodoc:
version = query("SHOW server_version")[0][0].split('.')
(version[0].to_i >= 8 && version[1].to_i >= 1) ? true : false
rescue
return false
end
def disable_referential_integrity(&block) #:nodoc:
if supports_disable_referential_integrity?() then
execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER ALL" }.join(";"))
end
yield
ensure
if supports_disable_referential_integrity?() then
execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER ALL" }.join(";"))
end
end
# DATABASE STATEMENTS ======================================
# Executes a SELECT query and returns an array of rows. Each row is an
# array of field values.
def select_rows(sql, name = nil)
select_raw(sql, name).last
end
# Executes an INSERT query and returns the new record's ID
def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
table = sql.split(" ", 4)[2].gsub('"', '')
super || pk && last_insert_id(table, sequence_name || default_sequence_name(table, pk))
end
# create a 2D array representing the result set
def result_as_array(res) #:nodoc:
ary = []
for i in 0...res.ntuples do
ary << []
for j in 0...res.nfields do
ary[i] << res.getvalue(i,j)
end
end
return ary
end
# Queries the database and returns the results in an Array-like object
def query(sql, name = nil) #:nodoc:
log(sql, name) do
if @async
res = @connection.async_exec(sql)
else
res = @connection.exec(sql)
end
return result_as_array(res)
end
end
# Executes an SQL statement, returning a PGresult object on success
# or raising a PGError exception otherwise.
def execute(sql, name = nil)
log(sql, name) do
if @async
@connection.async_exec(sql)
else
@connection.exec(sql)
end
end
end
# Executes an UPDATE query and returns the number of affected tuples.
def update_sql(sql, name = nil)
super.cmd_tuples
end
# Begins a transaction.
def begin_db_transaction
execute "BEGIN"
end
# Commits a transaction.
def commit_db_transaction
execute "COMMIT"
end
# Aborts a transaction.
def rollback_db_transaction
execute "ROLLBACK"
end
# SCHEMA STATEMENTS ========================================
def recreate_database(name) #:nodoc:
drop_database(name)
create_database(name)
end
# Create a new PostgreSQL database. Options include <tt>:owner</tt>, <tt>:template</tt>,
# <tt>:encoding</tt>, <tt>:tablespace</tt>, and <tt>:connection_limit</tt> (note that MySQL uses
# <tt>:charset</tt> while PostgreSQL uses <tt>:encoding</tt>).
#
# Example:
# create_database config[:database], config
# create_database 'foo_development', :encoding => 'unicode'
def create_database(name, options = {})
options = options.reverse_merge(:encoding => "utf8")
option_string = options.symbolize_keys.sum do |key, value|
case key
when :owner
" OWNER = '#{value}'"
when :template
" TEMPLATE = #{value}"
when :encoding
" ENCODING = '#{value}'"
when :tablespace
" TABLESPACE = #{value}"
when :connection_limit
" CONNECTION LIMIT = #{value}"
else
""
end
end
execute "CREATE DATABASE #{name}#{option_string}"
end
# Drops a PostgreSQL database
#
# Example:
# drop_database 'matt_development'
def drop_database(name) #:nodoc:
execute "DROP DATABASE IF EXISTS #{name}"
end
# Returns the list of all tables in the schema search path or a specified schema.
def tables(name = nil)
schemas = schema_search_path.split(/,/).map { |p| quote(p) }.join(',')
query(<<-SQL, name).map { |row| row[0] }
SELECT tablename
FROM pg_tables
WHERE schemaname IN (#{schemas})
SQL
end
# Returns the list of all indexes for a table.
def indexes(table_name, name = nil)
schemas = schema_search_path.split(/,/).map { |p| quote(p) }.join(',')
result = query(<<-SQL, name)
SELECT distinct i.relname, d.indisunique, a.attname
FROM pg_class t, pg_class i, pg_index d, pg_attribute a
WHERE i.relkind = 'i'
AND d.indexrelid = i.oid
AND d.indisprimary = 'f'
AND t.oid = d.indrelid
AND t.relname = '#{table_name}'
AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname IN (#{schemas}) )
AND a.attrelid = t.oid
AND ( d.indkey[0]=a.attnum OR d.indkey[1]=a.attnum
OR d.indkey[2]=a.attnum OR d.indkey[3]=a.attnum
OR d.indkey[4]=a.attnum OR d.indkey[5]=a.attnum
OR d.indkey[6]=a.attnum OR d.indkey[7]=a.attnum
OR d.indkey[8]=a.attnum OR d.indkey[9]=a.attnum )
ORDER BY i.relname
SQL
current_index = nil
indexes = []
result.each do |row|
if current_index != row[0]
indexes << IndexDefinition.new(table_name, row[0], row[1] == "t", [])
current_index = row[0]
end
indexes.last.columns << row[2]
end
indexes
end
# Returns the list of all column definitions for a table.
def columns(table_name, name = nil)
# Limit, precision, and scale are all handled by the superclass.
column_definitions(table_name).collect do |name, type, default, notnull|
PostgreSQLColumn.new(name, default, type, notnull == 'f')
end
end
# Sets the schema search path to a string of comma-separated schema names.
# Names beginning with $ have to be quoted (e.g. $user => '$user').
# See: http://www.postgresql.org/docs/current/static/ddl-schemas.html
#
# This should be not be called manually but set in database.yml.
def schema_search_path=(schema_csv)
if schema_csv
execute "SET search_path TO #{schema_csv}"
@schema_search_path = schema_csv
end
end
# Returns the active schema search path.
def schema_search_path
@schema_search_path ||= query('SHOW search_path')[0][0]
end
# Returns the current client message level.
def client_min_messages
query('SHOW client_min_messages')[0][0]
end
# Set the client message level.
def client_min_messages=(level)
execute("SET client_min_messages TO '#{level}'")
end
# Returns the sequence name for a table's primary key or some other specified key.
def default_sequence_name(table_name, pk = nil) #:nodoc:
default_pk, default_seq = pk_and_sequence_for(table_name)
default_seq || "#{table_name}_#{pk || default_pk || 'id'}_seq"
end
# Resets the sequence of a table's primary key to the maximum value.
def reset_pk_sequence!(table, pk = nil, sequence = nil) #:nodoc:
unless pk and sequence
default_pk, default_sequence = pk_and_sequence_for(table)
pk ||= default_pk
sequence ||= default_sequence
end
if pk
if sequence
quoted_sequence = quote_column_name(sequence)
select_value <<-end_sql, 'Reset sequence'
SELECT setval('#{quoted_sequence}', (SELECT COALESCE(MAX(#{quote_column_name pk})+(SELECT increment_by FROM #{quoted_sequence}), (SELECT min_value FROM #{quoted_sequence})) FROM #{quote_table_name(table)}), false)
end_sql
else
@logger.warn "#{table} has primary key #{pk} with no default sequence" if @logger
end
end
end
# Returns a table's primary key and belonging sequence.
def pk_and_sequence_for(table) #:nodoc:
# First try looking for a sequence with a dependency on the
# given table's primary key.
result = query(<<-end_sql, 'PK and serial sequence')[0]
SELECT attr.attname, seq.relname
FROM pg_class seq,
pg_attribute attr,
pg_depend dep,
pg_namespace name,
pg_constraint cons
WHERE seq.oid = dep.objid
AND seq.relkind = 'S'
AND attr.attrelid = dep.refobjid
AND attr.attnum = dep.refobjsubid
AND attr.attrelid = cons.conrelid
AND attr.attnum = cons.conkey[1]
AND cons.contype = 'p'
AND dep.refobjid = '#{table}'::regclass
end_sql
if result.nil? or result.empty?
# If that fails, try parsing the primary key's default value.
# Support the 7.x and 8.0 nextval('foo'::text) as well as
# the 8.1+ nextval('foo'::regclass).
result = query(<<-end_sql, 'PK and custom sequence')[0]
SELECT attr.attname,
CASE
WHEN split_part(def.adsrc, '''', 2) ~ '.' THEN
substr(split_part(def.adsrc, '''', 2),
strpos(split_part(def.adsrc, '''', 2), '.')+1)
ELSE split_part(def.adsrc, '''', 2)
END
FROM pg_class t
JOIN pg_attribute attr ON (t.oid = attrelid)
JOIN pg_attrdef def ON (adrelid = attrelid AND adnum = attnum)
JOIN pg_constraint cons ON (conrelid = adrelid AND adnum = conkey[1])
WHERE t.oid = '#{table}'::regclass
AND cons.contype = 'p'
AND def.adsrc ~* 'nextval'
end_sql
end
# [primary_key, sequence]
[result.first, result.last]
rescue
nil
end
# Renames a table.
def rename_table(name, new_name)
execute "ALTER TABLE #{name} RENAME TO #{new_name}"
end
# Adds a new column to the named table.
# See TableDefinition#column for details of the options you can use.
def add_column(table_name, column_name, type, options = {})
default = options[:default]
notnull = options[:null] == false
# Add the column.
execute("ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}")
change_column_default(table_name, column_name, default) if options_include_default?(options)
change_column_null(table_name, column_name, false, default) if notnull
end
# Changes the column of a table.
def change_column(table_name, column_name, type, options = {})
quoted_table_name = quote_table_name(table_name)
begin
execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
rescue ActiveRecord::StatementInvalid
# This is PostgreSQL 7.x, so we have to use a more arcane way of doing it.
begin
begin_db_transaction
tmp_column_name = "#{column_name}_ar_tmp"
add_column(table_name, tmp_column_name, type, options)
execute "UPDATE #{quoted_table_name} SET #{quote_column_name(tmp_column_name)} = CAST(#{quote_column_name(column_name)} AS #{type_to_sql(type, options[:limit], options[:precision], options[:scale])})"
remove_column(table_name, column_name)
rename_column(table_name, tmp_column_name, column_name)
commit_db_transaction
rescue
rollback_db_transaction
end
end
change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
end
# Changes the default value of a table column.
def change_column_default(table_name, column_name, default)
execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT #{quote(default)}"
end
def change_column_null(table_name, column_name, null, default = nil)
unless null || default.nil?
execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
end
execute("ALTER TABLE #{quote_table_name(table_name)} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
end
# Renames a column in a table.
def rename_column(table_name, column_name, new_column_name)
execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
end
# Drops an index from a table.
def remove_index(table_name, options = {})
execute "DROP INDEX #{index_name(table_name, options)}"
end
# Maps logical Rails types to PostgreSQL-specific data types.
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
return super unless type.to_s == 'integer'
if limit.nil? || limit == 4
'integer'
elsif limit < 4
'smallint'
else
'bigint'
end
end
# Returns a SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
#
# PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and
# requires that the ORDER BY include the distinct column.
#
# distinct("posts.id", "posts.created_at desc")
def distinct(columns, order_by) #:nodoc:
return "DISTINCT #{columns}" if order_by.blank?
# Construct a clean list of column names from the ORDER BY clause, removing
# any ASC/DESC modifiers
order_columns = order_by.split(',').collect { |s| s.split.first }
order_columns.delete_if &:blank?
order_columns = order_columns.zip((0...order_columns.size).to_a).map { |s,i| "#{s} AS alias_#{i}" }
# Return a DISTINCT ON() clause that's distinct on the columns we want but includes
# all the required columns for the ORDER BY to work properly.
sql = "DISTINCT ON (#{columns}) #{columns}, "
sql << order_columns * ', '
end
# Returns an ORDER BY clause for the passed order option.
#
# PostgreSQL does not allow arbitrary ordering when using DISTINCT ON, so we work around this
# by wrapping the +sql+ string as a sub-select and ordering in that query.
def add_order_by_for_association_limiting!(sql, options) #:nodoc:
return sql if options[:order].blank?
order = options[:order].split(',').collect { |s| s.strip }.reject(&:blank?)
order.map! { |s| 'DESC' if s =~ /\bdesc$/i }
order = order.zip((0...order.size).to_a).map { |s,i| "id_list.alias_#{i} #{s}" }.join(', ')
sql.replace "SELECT * FROM (#{sql}) AS id_list ORDER BY #{order}"
end
protected
# Returns the version of the connected PostgreSQL version.
def postgresql_version
@postgresql_version ||=
if @connection.respond_to?(:server_version)
@connection.server_version
else
# Mimic PGconn.server_version behavior
begin
query('SELECT version()')[0][0] =~ /PostgreSQL (\d+)\.(\d+)\.(\d+)/
($1.to_i * 10000) + ($2.to_i * 100) + $3.to_i
rescue
0
end
end
end
private
# The internal PostgreSQL identifier of the money data type.
MONEY_COLUMN_TYPE_OID = 790 #:nodoc:
# Connects to a PostgreSQL server and sets up the adapter depending on the
# connected server's characteristics.
def connect
@connection = PGconn.connect(*@connection_parameters)
PGconn.translate_results = false if PGconn.respond_to?(:translate_results=)
# Ignore async_exec and async_query when using postgres-pr.
@async = @config[:allow_concurrency] && @connection.respond_to?(:async_exec)
# Use escape string syntax if available. We cannot do this lazily when encountering
# the first string, because that could then break any transactions in progress.
# See: http://www.postgresql.org/docs/current/static/runtime-config-compatible.html
# If PostgreSQL doesn't know the standard_conforming_strings parameter then it doesn't
# support escape string syntax. Don't override the inherited quoted_string_prefix.
if supports_standard_conforming_strings?
self.class.instance_eval do
define_method(:quoted_string_prefix) { 'E' }
end
end
# Money type has a fixed precision of 10 in PostgreSQL 8.2 and below, and as of
# PostgreSQL 8.3 it has a fixed precision of 19. PostgreSQLColumn.extract_precision
# should know about this but can't detect it there, so deal with it here.
money_precision = (postgresql_version >= 80300) ? 19 : 10
PostgreSQLColumn.module_eval(<<-end_eval)
def extract_precision(sql_type)
if sql_type =~ /^money$/
#{money_precision}
else
super
end
end
end_eval
configure_connection
end
# Configures the encoding, verbosity, and schema search path of the connection.
# This is called by #connect and should not be called manually.
def configure_connection
if @config[:encoding]
if @connection.respond_to?(:set_client_encoding)
@connection.set_client_encoding(@config[:encoding])
else
execute("SET client_encoding TO '#{@config[:encoding]}'")
end
end
self.client_min_messages = @config[:min_messages] if @config[:min_messages]
self.schema_search_path = @config[:schema_search_path] || @config[:schema_order]
end
# Returns the current ID of a table's sequence.
def last_insert_id(table, sequence_name) #:nodoc:
Integer(select_value("SELECT currval('#{sequence_name}')"))
end
# Executes a SELECT query and returns the results, performing any data type
# conversions that are required to be performed here instead of in PostgreSQLColumn.
def select(sql, name = nil)
fields, rows = select_raw(sql, name)
result = []
for row in rows
row_hash = {}
fields.each_with_index do |f, i|
row_hash[f] = row[i]
end
result << row_hash
end
result
end
def select_raw(sql, name = nil)
res = execute(sql, name)
results = result_as_array(res)
fields = []
rows = []
if res.ntuples > 0
fields = res.fields
results.each do |row|
hashed_row = {}
row.each_index do |cell_index|
# If this is a money type column and there are any currency symbols,
# then strip them off. Indeed it would be prettier to do this in
# PostgreSQLColumn.string_to_decimal but would break form input
# fields that call value_before_type_cast.
if res.ftype(cell_index) == MONEY_COLUMN_TYPE_OID
# Because money output is formatted according to the locale, there are two
# cases to consider (note the decimal separators):
# (1) $12,345,678.12
# (2) $12.345.678,12
case column = row[cell_index]
when /^-?\D+[\d,]+\.\d{2}$/ # (1)
row[cell_index] = column.gsub(/[^-\d\.]/, '')
when /^-?\D+[\d\.]+,\d{2}$/ # (2)
row[cell_index] = column.gsub(/[^-\d,]/, '').sub(/,/, '.')
end
end
hashed_row[fields[cell_index]] = column
end
rows << row
end
end
res.clear
return fields, rows
end
# Returns the list of a table's column names, data types, and default values.
#
# The underlying query is roughly:
# SELECT column.name, column.type, default.value
# FROM column LEFT JOIN default
# ON column.table_id = default.table_id
# AND column.num = default.column_num
# WHERE column.table_id = get_table_id('table_name')
# AND column.num > 0
# AND NOT column.is_dropped
# ORDER BY column.num
#
# If the table name is not prefixed with a schema, the database will
# take the first match from the schema search path.
#
# Query implementation notes:
# - format_type includes the column size constraint, e.g. varchar(50)
# - ::regclass is a function that gives the id for a table name
def column_definitions(table_name) #:nodoc:
query <<-end_sql
SELECT a.attname, format_type(a.atttypid, a.atttypmod), d.adsrc, a.attnotnull
FROM pg_attribute a LEFT JOIN pg_attrdef d
ON a.attrelid = d.adrelid AND a.attnum = d.adnum
WHERE a.attrelid = '#{table_name}'::regclass
AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum
end_sql
end
end
end
end
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