949 lines
36 KiB
Ruby
949 lines
36 KiB
Ruby
require 'active_record/connection_adapters/abstract_adapter'
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begin
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require_library_or_gem 'pg'
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rescue LoadError => e
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begin
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require_library_or_gem 'postgres'
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class PGresult
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alias_method :nfields, :num_fields unless self.method_defined?(:nfields)
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alias_method :ntuples, :num_tuples unless self.method_defined?(:ntuples)
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alias_method :ftype, :type unless self.method_defined?(:ftype)
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alias_method :cmd_tuples, :cmdtuples unless self.method_defined?(:cmd_tuples)
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end
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rescue LoadError
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raise e
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end
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end
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module ActiveRecord
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class Base
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# Establishes a connection to the database that's used by all Active Record objects
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def self.postgresql_connection(config) # :nodoc:
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config = config.symbolize_keys
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host = config[:host]
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port = config[:port] || 5432
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username = config[:username].to_s
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password = config[:password].to_s
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if config.has_key?(:database)
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database = config[:database]
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else
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raise ArgumentError, "No database specified. Missing argument: database."
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end
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# The postgres drivers don't allow the creation of an unconnected PGconn object,
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# so just pass a nil connection object for the time being.
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ConnectionAdapters::PostgreSQLAdapter.new(nil, logger, [host, port, nil, nil, database, username, password], config)
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end
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end
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module ConnectionAdapters
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# PostgreSQL-specific extensions to column definitions in a table.
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class PostgreSQLColumn < Column #:nodoc:
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# Instantiates a new PostgreSQL column definition in a table.
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def initialize(name, default, sql_type = nil, null = true)
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super(name, self.class.extract_value_from_default(default), sql_type, null)
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end
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private
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# Extracts the scale from PostgreSQL-specific data types.
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def extract_scale(sql_type)
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# Money type has a fixed scale of 2.
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sql_type =~ /^money/ ? 2 : super
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end
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# Extracts the precision from PostgreSQL-specific data types.
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def extract_precision(sql_type)
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# Actual code is defined dynamically in PostgreSQLAdapter.connect
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# depending on the server specifics
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super
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end
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# Escapes binary strings for bytea input to the database.
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def self.string_to_binary(value)
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if PGconn.respond_to?(:escape_bytea)
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self.class.module_eval do
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define_method(:string_to_binary) do |value|
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PGconn.escape_bytea(value) if value
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end
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end
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else
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self.class.module_eval do
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define_method(:string_to_binary) do |value|
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if value
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result = ''
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value.each_byte { |c| result << sprintf('\\\\%03o', c) }
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result
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end
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end
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end
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end
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self.class.string_to_binary(value)
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end
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# Unescapes bytea output from a database to the binary string it represents.
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def self.binary_to_string(value)
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# In each case, check if the value actually is escaped PostgreSQL bytea output
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# or an unescaped Active Record attribute that was just written.
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if PGconn.respond_to?(:unescape_bytea)
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self.class.module_eval do
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define_method(:binary_to_string) do |value|
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if value =~ /\\\d{3}/
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PGconn.unescape_bytea(value)
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else
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value
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end
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end
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end
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else
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self.class.module_eval do
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define_method(:binary_to_string) do |value|
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if value =~ /\\\d{3}/
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result = ''
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i, max = 0, value.size
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while i < max
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char = value[i]
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if char == ?\\
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if value[i+1] == ?\\
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char = ?\\
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i += 1
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else
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char = value[i+1..i+3].oct
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i += 3
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end
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end
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result << char
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i += 1
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end
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result
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else
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value
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end
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end
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end
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end
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self.class.binary_to_string(value)
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end
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# Maps PostgreSQL-specific data types to logical Rails types.
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def simplified_type(field_type)
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case field_type
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# Numeric and monetary types
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when /^(?:real|double precision)$/
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:float
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# Monetary types
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when /^money$/
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:decimal
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# Character types
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when /^(?:character varying|bpchar)(?:\(\d+\))?$/
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:string
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# Binary data types
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when /^bytea$/
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:binary
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# Date/time types
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when /^timestamp with(?:out)? time zone$/
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:datetime
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when /^interval$/
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:string
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# Geometric types
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when /^(?:point|line|lseg|box|"?path"?|polygon|circle)$/
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:string
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# Network address types
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when /^(?:cidr|inet|macaddr)$/
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:string
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# Bit strings
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when /^bit(?: varying)?(?:\(\d+\))?$/
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:string
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# XML type
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when /^xml$/
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:string
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# Arrays
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when /^\D+\[\]$/
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:string
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# Object identifier types
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when /^oid$/
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:integer
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# Pass through all types that are not specific to PostgreSQL.
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else
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super
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end
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end
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# Extracts the value from a PostgreSQL column default definition.
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def self.extract_value_from_default(default)
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case default
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# Numeric types
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when /\A-?\d+(\.\d*)?\z/
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default
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# Character types
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when /\A'(.*)'::(?:character varying|bpchar|text)\z/m
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$1
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# Character types (8.1 formatting)
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when /\AE'(.*)'::(?:character varying|bpchar|text)\z/m
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$1.gsub(/\\(\d\d\d)/) { $1.oct.chr }
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# Binary data types
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when /\A'(.*)'::bytea\z/m
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$1
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# Date/time types
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when /\A'(.+)'::(?:time(?:stamp)? with(?:out)? time zone|date)\z/
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$1
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when /\A'(.*)'::interval\z/
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$1
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# Boolean type
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when 'true'
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true
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when 'false'
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false
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# Geometric types
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when /\A'(.*)'::(?:point|line|lseg|box|"?path"?|polygon|circle)\z/
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$1
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# Network address types
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when /\A'(.*)'::(?:cidr|inet|macaddr)\z/
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$1
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# Bit string types
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when /\AB'(.*)'::"?bit(?: varying)?"?\z/
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$1
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# XML type
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when /\A'(.*)'::xml\z/m
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$1
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# Arrays
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when /\A'(.*)'::"?\D+"?\[\]\z/
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$1
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# Object identifier types
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when /\A-?\d+\z/
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$1
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else
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# Anything else is blank, some user type, or some function
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# and we can't know the value of that, so return nil.
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nil
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end
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end
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end
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end
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module ConnectionAdapters
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# The PostgreSQL adapter works both with the native C (http://ruby.scripting.ca/postgres/) and the pure
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# Ruby (available both as gem and from http://rubyforge.org/frs/?group_id=234&release_id=1944) drivers.
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#
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# Options:
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#
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# * <tt>:host</tt> - Defaults to "localhost".
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# * <tt>:port</tt> - Defaults to 5432.
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# * <tt>:username</tt> - Defaults to nothing.
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# * <tt>:password</tt> - Defaults to nothing.
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# * <tt>:database</tt> - The name of the database. No default, must be provided.
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# * <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.
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# * <tt>:encoding</tt> - An optional client encoding that is used in a <tt>SET client_encoding TO <encoding></tt> call on the connection.
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# * <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.
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# * <tt>:allow_concurrency</tt> - If true, use async query methods so Ruby threads don't deadlock; otherwise, use blocking query methods.
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class PostgreSQLAdapter < AbstractAdapter
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# Returns 'PostgreSQL' as adapter name for identification purposes.
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def adapter_name
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'PostgreSQL'
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end
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# Initializes and connects a PostgreSQL adapter.
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def initialize(connection, logger, connection_parameters, config)
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super(connection, logger)
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@connection_parameters, @config = connection_parameters, config
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connect
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end
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# Is this connection alive and ready for queries?
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def active?
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if @connection.respond_to?(:status)
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@connection.status == PGconn::CONNECTION_OK
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else
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# We're asking the driver, not ActiveRecord, so use @connection.query instead of #query
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@connection.query 'SELECT 1'
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true
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end
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# postgres-pr raises a NoMethodError when querying if no connection is available.
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rescue PGError, NoMethodError
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false
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end
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# Close then reopen the connection.
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def reconnect!
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if @connection.respond_to?(:reset)
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@connection.reset
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configure_connection
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else
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disconnect!
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connect
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end
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end
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# Close the connection.
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def disconnect!
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@connection.close rescue nil
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end
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def native_database_types #:nodoc:
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{
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:primary_key => "serial primary key",
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:string => { :name => "character varying", :limit => 255 },
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:text => { :name => "text" },
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:integer => { :name => "integer" },
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:float => { :name => "float" },
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:decimal => { :name => "decimal" },
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:datetime => { :name => "timestamp" },
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:timestamp => { :name => "timestamp" },
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:time => { :name => "time" },
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:date => { :name => "date" },
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:binary => { :name => "bytea" },
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:boolean => { :name => "boolean" }
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}
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end
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# Does PostgreSQL support migrations?
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def supports_migrations?
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true
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end
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# Does PostgreSQL support standard conforming strings?
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def supports_standard_conforming_strings?
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# Temporarily set the client message level above error to prevent unintentional
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# error messages in the logs when working on a PostgreSQL database server that
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# does not support standard conforming strings.
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client_min_messages_old = client_min_messages
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self.client_min_messages = 'panic'
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# postgres-pr does not raise an exception when client_min_messages is set higher
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# than error and "SHOW standard_conforming_strings" fails, but returns an empty
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# PGresult instead.
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has_support = query('SHOW standard_conforming_strings')[0][0] rescue false
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self.client_min_messages = client_min_messages_old
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has_support
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end
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# Returns the configured supported identifier length supported by PostgreSQL,
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# or report the default of 63 on PostgreSQL 7.x.
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def table_alias_length
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@table_alias_length ||= (postgresql_version >= 80000 ? query('SHOW max_identifier_length')[0][0].to_i : 63)
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end
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# QUOTING ==================================================
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# Quotes PostgreSQL-specific data types for SQL input.
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def quote(value, column = nil) #:nodoc:
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if value.kind_of?(String) && column && column.type == :binary
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"#{quoted_string_prefix}'#{column.class.string_to_binary(value)}'"
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elsif value.kind_of?(String) && column && column.sql_type =~ /^xml$/
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"xml '#{quote_string(value)}'"
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elsif value.kind_of?(Numeric) && column && column.sql_type =~ /^money$/
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# Not truly string input, so doesn't require (or allow) escape string syntax.
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"'#{value.to_s}'"
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elsif value.kind_of?(String) && column && column.sql_type =~ /^bit/
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case value
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when /^[01]*$/
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"B'#{value}'" # Bit-string notation
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when /^[0-9A-F]*$/i
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"X'#{value}'" # Hexadecimal notation
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end
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else
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super
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end
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end
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# Quotes strings for use in SQL input in the postgres driver for better performance.
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def quote_string(s) #:nodoc:
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if PGconn.respond_to?(:escape)
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self.class.instance_eval do
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define_method(:quote_string) do |s|
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PGconn.escape(s)
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end
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end
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else
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# There are some incorrectly compiled postgres drivers out there
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# that don't define PGconn.escape.
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self.class.instance_eval do
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undef_method(:quote_string)
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end
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end
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quote_string(s)
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end
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# Quotes column names for use in SQL queries.
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def quote_column_name(name) #:nodoc:
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%("#{name}")
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end
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# Quote date/time values for use in SQL input. Includes microseconds
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# if the value is a Time responding to usec.
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def quoted_date(value) #:nodoc:
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if value.acts_like?(:time) && value.respond_to?(:usec)
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"#{super}.#{sprintf("%06d", value.usec)}"
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else
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super
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end
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end
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# REFERENTIAL INTEGRITY ====================================
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def supports_disable_referential_integrity?() #:nodoc:
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version = query("SHOW server_version")[0][0].split('.')
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(version[0].to_i >= 8 && version[1].to_i >= 1) ? true : false
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rescue
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return false
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end
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def disable_referential_integrity(&block) #:nodoc:
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if supports_disable_referential_integrity?() then
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execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} DISABLE TRIGGER ALL" }.join(";"))
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end
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yield
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ensure
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if supports_disable_referential_integrity?() then
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execute(tables.collect { |name| "ALTER TABLE #{quote_table_name(name)} ENABLE TRIGGER ALL" }.join(";"))
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end
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end
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# DATABASE STATEMENTS ======================================
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# Executes a SELECT query and returns an array of rows. Each row is an
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# array of field values.
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def select_rows(sql, name = nil)
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select_raw(sql, name).last
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end
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# Executes an INSERT query and returns the new record's ID
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def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
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table = sql.split(" ", 4)[2].gsub('"', '')
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super || pk && last_insert_id(table, sequence_name || default_sequence_name(table, pk))
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end
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# create a 2D array representing the result set
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def result_as_array(res) #:nodoc:
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ary = []
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for i in 0...res.ntuples do
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ary << []
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for j in 0...res.nfields do
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ary[i] << res.getvalue(i,j)
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end
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end
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return ary
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end
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# Queries the database and returns the results in an Array-like object
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def query(sql, name = nil) #:nodoc:
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log(sql, name) do
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if @async
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res = @connection.async_exec(sql)
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else
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res = @connection.exec(sql)
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end
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return result_as_array(res)
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end
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end
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# Executes an SQL statement, returning a PGresult object on success
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# or raising a PGError exception otherwise.
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def execute(sql, name = nil)
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log(sql, name) do
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if @async
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@connection.async_exec(sql)
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else
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@connection.exec(sql)
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end
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end
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end
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# Executes an UPDATE query and returns the number of affected tuples.
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def update_sql(sql, name = nil)
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super.cmd_tuples
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end
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|
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# Begins a transaction.
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def begin_db_transaction
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execute "BEGIN"
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end
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# Commits a transaction.
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def commit_db_transaction
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execute "COMMIT"
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end
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# Aborts a transaction.
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def rollback_db_transaction
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execute "ROLLBACK"
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end
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|
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# SCHEMA STATEMENTS ========================================
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def recreate_database(name) #:nodoc:
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drop_database(name)
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create_database(name)
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end
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|
|
# Create a new PostgreSQL database. Options include <tt>:owner</tt>, <tt>:template</tt>,
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# <tt>:encoding</tt>, <tt>:tablespace</tt>, and <tt>:connection_limit</tt> (note that MySQL uses
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# <tt>:charset</tt> while PostgreSQL uses <tt>:encoding</tt>).
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|
#
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|
# Example:
|
|
# create_database config[:database], config
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|
# create_database 'foo_development', :encoding => 'unicode'
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def create_database(name, options = {})
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options = options.reverse_merge(:encoding => "utf8")
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option_string = options.symbolize_keys.sum do |key, value|
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case key
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when :owner
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" OWNER = '#{value}'"
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when :template
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" TEMPLATE = #{value}"
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when :encoding
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" ENCODING = '#{value}'"
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when :tablespace
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" TABLESPACE = #{value}"
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when :connection_limit
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" CONNECTION LIMIT = #{value}"
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else
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""
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end
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end
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execute "CREATE DATABASE #{name}#{option_string}"
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end
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|
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# Drops a PostgreSQL database
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|
#
|
|
# Example:
|
|
# drop_database 'matt_development'
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|
def drop_database(name) #:nodoc:
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|
execute "DROP DATABASE IF EXISTS #{name}"
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end
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|
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# Returns the list of all tables in the schema search path or a specified schema.
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|
def tables(name = nil)
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|
schemas = schema_search_path.split(/,/).map { |p| quote(p) }.join(',')
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query(<<-SQL, name).map { |row| row[0] }
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SELECT tablename
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FROM pg_tables
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WHERE schemaname IN (#{schemas})
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SQL
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end
|
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|
|
# 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) + $3.to_i
|
|
rescue
|
|
0
|
|
end
|
|
end
|
|
end
|
|
|
|
private
|
|
# The internal PostgreSQL identifer of the money data type.
|
|
MONEY_COLUMN_TYPE_OID = 790 #:nodoc:
|
|
|
|
# Connects to a PostgreSQL server and sets up the adapter depending on the
|
|
# connected server's characteristics.
|
|
def connect
|
|
@connection = PGconn.connect(*@connection_parameters)
|
|
PGconn.translate_results = false if PGconn.respond_to?(:translate_results=)
|
|
|
|
# Ignore async_exec and async_query when using postgres-pr.
|
|
@async = @config[:allow_concurrency] && @connection.respond_to?(:async_exec)
|
|
|
|
# Use escape string syntax if available. We cannot do this lazily when encountering
|
|
# the first string, because that could then break any transactions in progress.
|
|
# See: http://www.postgresql.org/docs/current/static/runtime-config-compatible.html
|
|
# If PostgreSQL doesn't know the standard_conforming_strings parameter then it doesn't
|
|
# support escape string syntax. Don't override the inherited quoted_string_prefix.
|
|
if supports_standard_conforming_strings?
|
|
self.class.instance_eval do
|
|
define_method(:quoted_string_prefix) { 'E' }
|
|
end
|
|
end
|
|
|
|
# Money type has a fixed precision of 10 in PostgreSQL 8.2 and below, and as of
|
|
# PostgreSQL 8.3 it has a fixed precision of 19. PostgreSQLColumn.extract_precision
|
|
# should know about this but can't detect it there, so deal with it here.
|
|
money_precision = (postgresql_version >= 80300) ? 19 : 10
|
|
PostgreSQLColumn.module_eval(<<-end_eval)
|
|
def extract_precision(sql_type)
|
|
if sql_type =~ /^money$/
|
|
#{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
|