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 if config[:username] password = config[:password].to_s if config[:password] 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 class TableDefinition def xml(*args) options = args.extract_options! column(args[0], 'xml', options) end end # 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 def extract_limit(sql_type) case sql_type when /^bigint/i; 8 when /^smallint/i; 2 else super end end # 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 # 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)?(?:\(\d+\))?$/ :string # XML type when /^xml$/ :xml # 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/ $1 # 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: # # * :host - Defaults to "localhost". # * :port - Defaults to 5432. # * :username - Defaults to nothing. # * :password - Defaults to nothing. # * :database - The name of the database. No default, must be provided. # * :schema_search_path - An optional schema search path for the connection given as a string of comma-separated schema names. This is backward-compatible with the :schema_order option. # * :encoding - An optional client encoding that is used in a SET client_encoding TO call on the connection. # * :min_messages - An optional client min messages that is used in a SET client_min_messages TO call on the connection. # * :allow_concurrency - If true, use async query methods so Ruby threads don't deadlock; otherwise, use blocking query methods. class PostgreSQLAdapter < AbstractAdapter ADAPTER_NAME = 'PostgreSQL'.freeze NATIVE_DATABASE_TYPES = { :primary_key => "serial primary key".freeze, :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" }, :xml => { :name => "xml" } } # Returns 'PostgreSQL' as adapter name for identification purposes. def adapter_name ADAPTER_NAME 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: NATIVE_DATABASE_TYPES end # Does PostgreSQL support migrations? def supports_migrations? true end # Does PostgreSQL support finding primary key on non-ActiveRecord tables? def supports_primary_key? #:nodoc: 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 def supports_insert_with_returning? postgresql_version >= 80200 end def supports_ddl_transactions? true end def supports_savepoints? true 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 ================================================== # Escapes binary strings for bytea input to the database. def escape_bytea(value) if @connection.respond_to?(:escape_bytea) self.class.instance_eval do define_method(:escape_bytea) do |value| @connection.escape_bytea(value) if value end end elsif PGconn.respond_to?(:escape_bytea) self.class.instance_eval do define_method(:escape_bytea) do |value| PGconn.escape_bytea(value) if value end end else self.class.instance_eval do define_method(:escape_bytea) do |value| if value result = '' value.each_byte { |c| result << sprintf('\\\\%03o', c) } result end end end end escape_bytea(value) end # Unescapes bytea output from a database to the binary string it represents. # NOTE: This is NOT an inverse of escape_bytea! This is only to be used # on escaped binary output from database drive. def unescape_bytea(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.instance_eval do define_method(:unescape_bytea) do |value| if value =~ /\\\d{3}/ PGconn.unescape_bytea(value) else value end end end else self.class.instance_eval do define_method(:unescape_bytea) 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 unescape_bytea(value) end # 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}'#{escape_bytea(value)}'" elsif value.kind_of?(String) && column && column.sql_type =~ /^xml$/ "xml E'#{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 @connection.respond_to?(:escape) self.class.instance_eval do define_method(:quote_string) do |s| @connection.escape(s) end end elsif 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 remove_method(:quote_string) end end quote_string(s) end # Checks the following cases: # # - table_name # - "table.name" # - schema_name.table_name # - schema_name."table.name" # - "schema.name".table_name # - "schema.name"."table.name" def quote_table_name(name) schema, name_part = extract_pg_identifier_from_name(name.to_s) unless name_part quote_column_name(schema) else table_name, name_part = extract_pg_identifier_from_name(name_part) "#{quote_column_name(schema)}.#{quote_column_name(table_name)}" end end # Quotes column names for use in SQL queries. def quote_column_name(name) #:nodoc: PGconn.quote_ident(name.to_s) 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) # Extract the table from the insert sql. Yuck. table = sql.split(" ", 4)[2].gsub('"', '') # Try an insert with 'returning id' if available (PG >= 8.2) if supports_insert_with_returning? pk, sequence_name = *pk_and_sequence_for(table) unless pk if pk id = select_value("#{sql} RETURNING #{quote_column_name(pk)}") clear_query_cache return id end end # Otherwise, insert then grab last_insert_id. if insert_id = super insert_id else # If neither pk nor sequence name is given, look them up. unless pk || sequence_name pk, sequence_name = *pk_and_sequence_for(table) end # If a pk is given, fallback to default sequence name. # Don't fetch last insert id for a table without a pk. if pk && sequence_name ||= default_sequence_name(table, pk) last_insert_id(table, sequence_name) end end end # create a 2D array representing the result set def result_as_array(res) #:nodoc: # check if we have any binary column and if they need escaping unescape_col = [] for j in 0...res.nfields do # unescape string passed BYTEA field (OID == 17) unescape_col << ( res.ftype(j)==17 ) end ary = [] for i in 0...res.ntuples do ary << [] for j in 0...res.nfields do data = res.getvalue(i,j) data = unescape_bytea(data) if unescape_col[j] and data.is_a?(String) ary[i] << data 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 if defined?(PGconn::PQTRANS_IDLE) # The ruby-pg driver supports inspecting the transaction status, # while the ruby-postgres driver does not. def outside_transaction? @connection.transaction_status == PGconn::PQTRANS_IDLE end end def create_savepoint execute("SAVEPOINT #{current_savepoint_name}") end def rollback_to_savepoint execute("ROLLBACK TO SAVEPOINT #{current_savepoint_name}") end def release_savepoint execute("RELEASE SAVEPOINT #{current_savepoint_name}") end # SCHEMA STATEMENTS ======================================== def recreate_database(name) #:nodoc: drop_database(name) create_database(name) end # Create a new PostgreSQL database. Options include :owner, :template, # :encoding, :tablespace, and :connection_limit (note that MySQL uses # :charset while PostgreSQL uses :encoding). # # 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 #{quote_table_name(name)}#{option_string}" end # Drops a PostgreSQL database # # Example: # drop_database 'matt_development' def drop_database(name) #:nodoc: if postgresql_version >= 80200 execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}" else begin execute "DROP DATABASE #{quote_table_name(name)}" rescue ActiveRecord::StatementInvalid @logger.warn "#{name} database doesn't exist." if @logger end end 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, d.indkey, t.oid FROM pg_class t, pg_class i, pg_index d 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}) ) ORDER BY i.relname SQL indexes = [] indexes = result.map do |row| index_name = row[0] unique = row[1] == 't' indkey = row[2].split(" ") oid = row[3] columns = query(<<-SQL, "Columns for index #{row[0]} on #{table_name}").inject({}) {|attlist, r| attlist[r[1]] = r[0]; attlist} SELECT a.attname, a.attnum FROM pg_attribute a WHERE a.attrelid = #{oid} AND a.attnum IN (#{indkey.join(",")}) SQL column_names = indkey.map {|attnum| columns[attnum] } IndexDefinition.new(table_name, index_name, unique, column_names) 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 # Returns the current database name. def current_database query('select current_database()')[0][0] end # Returns the current database encoding format. def encoding query(<<-end_sql)[0][0] SELECT pg_encoding_to_char(pg_database.encoding) FROM pg_database WHERE pg_database.datname LIKE '#{current_database}' end_sql 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 = '#{quote_table_name(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 = '#{quote_table_name(table)}'::regclass AND cons.contype = 'p' AND def.adsrc ~* 'nextval' end_sql end # [primary_key, sequence] [result.first, result.last] rescue nil end # Returns just a table's primary key def primary_key(table) pk_and_sequence = pk_and_sequence_for(table) pk_and_sequence && pk_and_sequence.first end # Renames a table. def rename_table(name, new_name) execute "ALTER TABLE #{quote_table_name(name)} RENAME TO #{quote_table_name(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 => e raise e if postgresql_version > 80000 # 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 #{quote_table_name(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' case limit when 1..2; 'smallint' when 3..4, nil; 'integer' when 5..8; 'bigint' else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with precision 0 instead.") 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) + $3.to_i rescue 0 end end end private # The internal PostgreSQL identifier of the money data type. MONEY_COLUMN_TYPE_OID = 790 #:nodoc: # Connects to a PostgreSQL server and sets up the adapter depending on the # connected server's characteristics. def connect @connection = PGconn.connect(*@connection_parameters) PGconn.translate_results = false if PGconn.respond_to?(:translate_results=) # Ignore async_exec and async_query when using postgres-pr. @async = @config[:allow_concurrency] && @connection.respond_to?(:async_exec) # Use escape string syntax if available. We cannot do this lazily when encountering # the first string, because that could then break any transactions in progress. # See: http://www.postgresql.org/docs/current/static/runtime-config-compatible.html # If PostgreSQL doesn't know the standard_conforming_strings parameter then it doesn't # support escape string syntax. Don't override the inherited quoted_string_prefix. if supports_standard_conforming_strings? self.class.instance_eval do define_method(:quoted_string_prefix) { 'E' } end end # Money type has a fixed precision of 10 in PostgreSQL 8.2 and below, and as of # PostgreSQL 8.3 it has a fixed precision of 19. PostgreSQLColumn.extract_precision # should know about this but can't detect it there, so deal with it here. money_precision = (postgresql_version >= 80300) ? 19 : 10 PostgreSQLColumn.module_eval(<<-end_eval) def extract_precision(sql_type) # def extract_precision(sql_type) if sql_type =~ /^money$/ # if sql_type =~ /^money$/ #{money_precision} # 19 else # else super # super end # end 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 = '#{quote_table_name(table_name)}'::regclass AND a.attnum > 0 AND NOT a.attisdropped ORDER BY a.attnum end_sql end def extract_pg_identifier_from_name(name) match_data = name[0,1] == '"' ? name.match(/\"([^\"]+)\"/) : name.match(/([^\.]+)/) if match_data rest = name[match_data[0].length..-1] rest = rest[1..-1] if rest[0,1] == "." [match_data[1], (rest.length > 0 ? rest : nil)] end end end end end