require 'active_record/connection_adapters/abstract_adapter' require 'active_support/core_ext/object/blank' require 'active_record/connection_adapters/statement_pool' require 'arel/visitors/bind_visitor' # Make sure we're using pg high enough for PGResult#values gem 'pg', '~> 0.11' require 'pg' 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.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 # :stopdoc: class << self attr_accessor :money_precision def string_to_time(string) return string unless String === string case string when 'infinity' then 1.0 / 0.0 when '-infinity' then -1.0 / 0.0 else super end end end # :startdoc: 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) if sql_type == 'money' self.class.money_precision else super end 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 # tsvector type when 'tsvector' :tsvector # Arrays when /^\D+\[\]$/ :string # Object identifier types when 'oid' :integer # UUID type when 'uuid' :string # Small and big integer types when /^(?:small|big)int$/ :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 # This is a performance optimization for Ruby 1.9.2 in development. # If the value is nil, we return nil straight away without checking # the regular expressions. If we check each regular expression, # Regexp#=== will call NilClass#to_str, which will trigger # method_missing (defined by whiny nil in ActiveSupport) which # makes this method very very slow. when NilClass nil # Numeric types when /\A\(?(-?\d+(\.\d*)?\)?(::bigint)?)\z/ $1 # Character types when /\A\(?'(.*)'::.*\b(?:character varying|bpchar|text)\z/m $1 # 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 # 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. class PostgreSQLAdapter < AbstractAdapter class TableDefinition < ActiveRecord::ConnectionAdapters::TableDefinition def xml(*args) options = args.extract_options! column(args[0], 'xml', options) end def tsvector(*args) options = args.extract_options! column(args[0], 'tsvector', options) end end ADAPTER_NAME = 'PostgreSQL' NATIVE_DATABASE_TYPES = { :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" }, :xml => { :name => "xml" }, :tsvector => { :name => "tsvector" } } # Returns 'PostgreSQL' as adapter name for identification purposes. def adapter_name ADAPTER_NAME end # Returns +true+, since this connection adapter supports prepared statement # caching. def supports_statement_cache? true end def supports_index_sort_order? true end class StatementPool < ConnectionAdapters::StatementPool def initialize(connection, max) super @counter = 0 @cache = Hash.new { |h,pid| h[pid] = {} } end def each(&block); cache.each(&block); end def key?(key); cache.key?(key); end def [](key); cache[key]; end def length; cache.length; end def next_key "a#{@counter + 1}" end def []=(sql, key) while @max <= cache.size dealloc(cache.shift.last) end @counter += 1 cache[sql] = key end def clear cache.each_value do |stmt_key| dealloc stmt_key end cache.clear end def delete(sql_key) dealloc cache[sql_key] cache.delete sql_key end private def cache @cache[$$] end def dealloc(key) @connection.query "DEALLOCATE #{key}" if connection_active? end def connection_active? @connection.status == PGconn::CONNECTION_OK rescue PGError false end end class BindSubstitution < Arel::Visitors::PostgreSQL # :nodoc: include Arel::Visitors::BindVisitor end # Initializes and connects a PostgreSQL adapter. def initialize(connection, logger, connection_parameters, config) super(connection, logger) if config.fetch(:prepared_statements) { true } @visitor = Arel::Visitors::PostgreSQL.new self else @visitor = BindSubstitution.new self end @connection_parameters, @config = connection_parameters, config # @local_tz is initialized as nil to avoid warnings when connect tries to use it @local_tz = nil @table_alias_length = nil connect @statements = StatementPool.new @connection, config.fetch(:statement_limit) { 1000 } if postgresql_version < 80200 raise "Your version of PostgreSQL (#{postgresql_version}) is too old, please upgrade!" end @local_tz = execute('SHOW TIME ZONE', 'SCHEMA').first["TimeZone"] end # Clears the prepared statements cache. def clear_cache! @statements.clear end # Is this connection alive and ready for queries? def active? @connection.query 'SELECT 1' true rescue PGError false end # Close then reopen the connection. def reconnect! clear_cache! @connection.reset @open_transactions = 0 configure_connection end def reset! clear_cache! super end # Disconnects from the database if already connected. Otherwise, this # method does nothing. def disconnect! clear_cache! @connection.close rescue nil end def native_database_types #:nodoc: NATIVE_DATABASE_TYPES end # Returns true, since this connection adapter supports migrations. def supports_migrations? true end # Does PostgreSQL support finding primary key on non-Active Record tables? def supports_primary_key? #:nodoc: true end # Enable standard-conforming strings if available. def set_standard_conforming_strings old, self.client_min_messages = client_min_messages, 'panic' execute('SET standard_conforming_strings = on', 'SCHEMA') rescue nil ensure self.client_min_messages = old end def supports_insert_with_returning? true end def supports_ddl_transactions? true end # Returns true, since this connection adapter supports savepoints. def supports_savepoints? true end # Returns true. def supports_explain? true end # Returns the configured supported identifier length supported by PostgreSQL def table_alias_length @table_alias_length ||= query('SHOW max_identifier_length')[0][0].to_i end # QUOTING ================================================== # Escapes binary strings for bytea input to the database. def escape_bytea(value) @connection.escape_bytea(value) if 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) @connection.unescape_bytea(value) if value end # Quotes PostgreSQL-specific data types for SQL input. def quote(value, column = nil) #:nodoc: return super unless column case value when Float return super unless value.infinite? && column.type == :datetime "'#{value.to_s.downcase}'" when Numeric return super unless column.sql_type == 'money' # Not truly string input, so doesn't require (or allow) escape string syntax. "'#{value}'" when String case column.sql_type when 'bytea' then "'#{escape_bytea(value)}'" when 'xml' then "xml '#{quote_string(value)}'" when /^bit/ case value when /\A[01]*\Z/ then "B'#{value}'" # Bit-string notation when /\A[0-9A-F]*\Z/i then "X'#{value}'" # Hexadecimal notation end else super end else super end end def type_cast(value, column) return super unless column case value when String return super unless 'bytea' == column.sql_type { :value => value, :format => 1 } else super end end # Quotes strings for use in SQL input. def quote_string(s) #:nodoc: @connection.escape(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 # Set the authorized user for this session def session_auth=(user) clear_cache! exec_query "SET SESSION AUTHORIZATION #{user}" end # REFERENTIAL INTEGRITY ==================================== def supports_disable_referential_integrity? #:nodoc: true end def disable_referential_integrity #: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 ====================================== def explain(arel, binds = []) sql = "EXPLAIN #{to_sql(arel, binds)}" ExplainPrettyPrinter.new.pp(exec_query(sql, 'EXPLAIN', binds)) end class ExplainPrettyPrinter # :nodoc: # Pretty prints the result of a EXPLAIN in a way that resembles the output of the # PostgreSQL shell: # # QUERY PLAN # ------------------------------------------------------------------------------ # Nested Loop Left Join (cost=0.00..37.24 rows=8 width=0) # Join Filter: (posts.user_id = users.id) # -> Index Scan using users_pkey on users (cost=0.00..8.27 rows=1 width=4) # Index Cond: (id = 1) # -> Seq Scan on posts (cost=0.00..28.88 rows=8 width=4) # Filter: (posts.user_id = 1) # (6 rows) # def pp(result) header = result.columns.first lines = result.rows.map(&:first) # We add 2 because there's one char of padding at both sides, note # the extra hyphens in the example above. width = [header, *lines].map(&:length).max + 2 pp = [] pp << header.center(width).rstrip pp << '-' * width pp += lines.map {|line| " #{line}"} nrows = result.rows.length rows_label = nrows == 1 ? 'row' : 'rows' pp << "(#{nrows} #{rows_label})" pp.join("\n") + "\n" end end # 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(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) unless pk # Extract the table from the insert sql. Yuck. table_ref = extract_table_ref_from_insert_sql(sql) pk = primary_key(table_ref) if table_ref end if pk select_value("#{sql} RETURNING #{quote_column_name(pk)}") else super end end alias :create :insert # 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 ftypes = Array.new(res.nfields) do |i| [i, res.ftype(i)] end rows = res.values return rows unless ftypes.any? { |_, x| x == BYTEA_COLUMN_TYPE_OID || x == MONEY_COLUMN_TYPE_OID } typehash = ftypes.group_by { |_, type| type } binaries = typehash[BYTEA_COLUMN_TYPE_OID] || [] monies = typehash[MONEY_COLUMN_TYPE_OID] || [] rows.each do |row| # unescape string passed BYTEA field (OID == 17) binaries.each do |index, _| row[index] = unescape_bytea(row[index]) end # 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. monies.each do |index, _| data = row[index] # 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) $12.345.678,12 case data when /^-?\D+[\d,]+\.\d{2}$/ # (1) data.gsub!(/[^-\d.]/, '') when /^-?\D+[\d.]+,\d{2}$/ # (2) data.gsub!(/[^-\d,]/, '').sub!(/,/, '.') end end end end # Queries the database and returns the results in an Array-like object def query(sql, name = nil) #:nodoc: log(sql, name) do result_as_array @connection.async_exec(sql) end end # Executes an SQL statement, returning a PGresult object on success # or raising a PGError exception otherwise. def execute(sql, name = nil) log(sql, name) do @connection.async_exec(sql) end end def substitute_at(column, index) Arel::Nodes::BindParam.new "$#{index + 1}" end def exec_query(sql, name = 'SQL', binds = []) log(sql, name, binds) do result = binds.empty? ? exec_no_cache(sql, binds) : exec_cache(sql, binds) ret = ActiveRecord::Result.new(result.fields, result_as_array(result)) result.clear return ret end end def exec_delete(sql, name = 'SQL', binds = []) log(sql, name, binds) do result = binds.empty? ? exec_no_cache(sql, binds) : exec_cache(sql, binds) affected = result.cmd_tuples result.clear affected end end alias :exec_update :exec_delete def sql_for_insert(sql, pk, id_value, sequence_name, binds) unless pk # Extract the table from the insert sql. Yuck. table_ref = extract_table_ref_from_insert_sql(sql) pk = primary_key(table_ref) if table_ref end sql = "#{sql} RETURNING #{quote_column_name(pk)}" if pk [sql, binds] 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 def outside_transaction? @connection.transaction_status == PGconn::PQTRANS_IDLE 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 ======================================== # Drops the database specified on the +name+ attribute # and creates it again using the provided +options+. def recreate_database(name, options = {}) #:nodoc: drop_database(name) create_database(name, options) 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: execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}" end # Returns the list of all tables in the schema search path or a specified schema. def tables(name = nil) query(<<-SQL, 'SCHEMA').map { |row| row[0] } SELECT tablename FROM pg_tables WHERE schemaname = ANY (current_schemas(false)) SQL end # Returns true if table exists. # If the schema is not specified as part of +name+ then it will only find tables within # the current schema search path (regardless of permissions to access tables in other schemas) def table_exists?(name) schema, table = Utils.extract_schema_and_table(name.to_s) return false unless table binds = [[nil, table]] binds << [nil, schema] if schema exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0 SELECT COUNT(*) FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace WHERE c.relkind in ('v','r') AND c.relname = '#{table.gsub(/(^"|"$)/,'')}' AND n.nspname = #{schema ? "'#{schema}'" : 'ANY (current_schemas(false))'} SQL end # Returns true if schema exists. def schema_exists?(name) exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0 SELECT COUNT(*) FROM pg_namespace WHERE nspname = '#{name}' SQL end # Returns an array of indexes for the given table. def indexes(table_name, name = nil) result = query(<<-SQL, 'SCHEMA') SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid FROM pg_class t INNER JOIN pg_index d ON t.oid = d.indrelid INNER JOIN pg_class i ON d.indexrelid = i.oid WHERE i.relkind = 'i' AND d.indisprimary = 'f' AND t.relname = '#{table_name}' AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) ) ORDER BY i.relname SQL result.map do |row| index_name = row[0] unique = row[1] == 't' indkey = row[2].split(" ") inddef = row[3] oid = row[4] columns = Hash[query(<<-SQL, "SCHEMA")] SELECT a.attnum, a.attname FROM pg_attribute a WHERE a.attrelid = #{oid} AND a.attnum IN (#{indkey.join(",")}) SQL column_names = columns.values_at(*indkey).compact # add info on sort order for columns (only desc order is explicitly specified, asc is the default) desc_order_columns = inddef.scan(/(\w+) DESC/).flatten orders = desc_order_columns.any? ? Hash[desc_order_columns.map {|order_column| [order_column, :desc]}] : {} column_names.empty? ? nil : IndexDefinition.new(table_name, index_name, unique, column_names, [], orders) end.compact 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 |column_name, type, default, notnull| PostgreSQLColumn.new(column_name, default, type, notnull == 'f') end end # Returns the current database name. def current_database query('select current_database()', 'SCHEMA')[0][0] end # Returns the current schema name. def current_schema query('SELECT current_schema', 'SCHEMA')[0][0] end # Returns the current database encoding format. def encoding query(<<-end_sql, 'SCHEMA')[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') @schema_search_path = schema_csv end end # Returns the active schema search path. def schema_search_path @schema_search_path ||= query('SHOW search_path', 'SCHEMA')[0][0] end # Returns the current client message level. def client_min_messages query('SHOW client_min_messages', 'SCHEMA')[0][0] end # Set the client message level. def client_min_messages=(level) execute("SET client_min_messages TO '#{level}'", 'SCHEMA') 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: serial_sequence(table_name, pk || 'id').split('.').last rescue ActiveRecord::StatementInvalid "#{table_name}_#{pk || 'id'}_seq" end def serial_sequence(table, column) result = exec_query(<<-eosql, 'SCHEMA') SELECT pg_get_serial_sequence('#{table}', '#{column}') eosql result.rows.first.first 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 @logger && pk && !sequence @logger.warn "#{table} has primary key #{pk} with no default sequence" end if pk && sequence quoted_sequence = quote_table_name(sequence) select_value <<-end_sql, 'SCHEMA' 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 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, 'SCHEMA')[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? result = query(<<-end_sql, 'SCHEMA')[0] SELECT attr.attname, CASE WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1) ELSE split_part(pg_get_expr(def.adbin, def.adrelid), '''', 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 pg_get_expr(def.adbin, def.adrelid) ~* 'nextval' end_sql end [result.first, result.last] rescue nil end # Returns just a table's primary key def primary_key(table) row = exec_query(<<-end_sql, 'SCHEMA').rows.first SELECT attr.attname FROM pg_attribute attr INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1] WHERE cons.contype = 'p' AND cons.conrelid = '#{quote_table_name(table)}'::regclass end_sql row && row.first end # Renames a table. # Also renames a table's primary key sequence if the sequence name matches the # Active Record default. # # Example: # rename_table('octopuses', 'octopi') def rename_table(name, new_name) clear_cache! execute "ALTER TABLE #{quote_table_name(name)} RENAME TO #{quote_table_name(new_name)}" pk, seq = pk_and_sequence_for(new_name) if seq == "#{name}_#{pk}_seq" new_seq = "#{new_name}_#{pk}_seq" execute "ALTER TABLE #{quote_table_name(seq)} RENAME TO #{quote_table_name(new_seq)}" end 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 = {}) clear_cache! add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD COLUMN #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}" add_column_options!(add_column_sql, options) execute add_column_sql end # Changes the column of a table. def change_column(table_name, column_name, type, options = {}) clear_cache! quoted_table_name = quote_table_name(table_name) execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}" 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) clear_cache! 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) clear_cache! 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) clear_cache! execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}" end def remove_index!(table_name, index_name) #:nodoc: execute "DROP INDEX #{quote_table_name(index_name)}" end def rename_index(table_name, old_name, new_name) execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}" end def index_name_length 63 end # Maps logical Rails types to PostgreSQL-specific data types. def type_to_sql(type, limit = nil, precision = nil, scale = nil) case type.to_s when 'binary' # PostgreSQL doesn't support limits on binary (bytea) columns. # The hard limit is 1Gb, because of a 32-bit size field, and TOAST. case limit when nil, 0..0x3fffffff; super(type) else raise(ActiveRecordError, "No binary type has byte size #{limit}.") end when 'text' # PostgreSQL doesn't support limits on text columns. # The hard limit is 1Gb, according to section 8.3 in the manual. case limit when nil, 0..0x3fffffff; super(type) else raise(ActiveRecordError, "The limit on text can be at most 1GB - 1byte.") end when 'integer' return 'integer' unless limit case limit when 1, 2; 'smallint' when 3, 4; 'integer' when 5..8; 'bigint' else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with precision 0 instead.") end else super 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, orders) #:nodoc: return "DISTINCT #{columns}" if orders.empty? # Construct a clean list of column names from the ORDER BY clause, removing # any ASC/DESC modifiers order_columns = orders.collect { |s| s.gsub(/\s+(ASC|DESC)\s*(NULLS\s+(FIRST|LAST)\s*)?/i, '') } order_columns.delete_if { |c| c.blank? } order_columns = order_columns.zip((0...order_columns.size).to_a).map { |s,i| "#{s} AS alias_#{i}" } "DISTINCT #{columns}, #{order_columns * ', '}" end module Utils extend self # Returns an array of [schema_name, table_name] extracted from +name+. # +schema_name+ is nil if not specified in +name+. # +schema_name+ and +table_name+ exclude surrounding quotes (regardless of whether provided in +name+) # +name+ supports the range of schema/table references understood by PostgreSQL, for example: # # * table_name # * "table.name" # * schema_name.table_name # * schema_name."table.name" # * "schema.name"."table name" def extract_schema_and_table(name) table, schema = name.scan(/[^".\s]+|"[^"]*"/)[0..1].collect{|m| m.gsub(/(^"|"$)/,'') }.reverse [schema, table] end end protected # Returns the version of the connected PostgreSQL server. def postgresql_version @connection.server_version end # See http://www.postgresql.org/docs/9.1/static/errcodes-appendix.html FOREIGN_KEY_VIOLATION = "23503" UNIQUE_VIOLATION = "23505" def translate_exception(exception, message) return exception unless exception.respond_to?(:result) case exception.result.try(:error_field, PGresult::PG_DIAG_SQLSTATE) when UNIQUE_VIOLATION RecordNotUnique.new(message, exception) when FOREIGN_KEY_VIOLATION InvalidForeignKey.new(message, exception) else super end end private FEATURE_NOT_SUPPORTED = "0A000" # :nodoc: def exec_no_cache(sql, binds) @connection.async_exec(sql, []) end def exec_cache(sql, binds) begin stmt_key = prepare_statement sql # Clear the queue @connection.get_last_result @connection.send_query_prepared(stmt_key, binds.map { |col, val| type_cast(val, col) }) @connection.block @connection.get_last_result rescue PGError => e # Get the PG code for the failure. Annoyingly, the code for # prepared statements whose return value may have changed is # FEATURE_NOT_SUPPORTED. Check here for more details: # http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=src/backend/utils/cache/plancache.c#l573 begin code = e.result.result_error_field(PGresult::PG_DIAG_SQLSTATE) rescue raise e end if FEATURE_NOT_SUPPORTED == code @statements.delete sql_key(sql) retry else raise e end end end # Returns the statement identifier for the client side cache # of statements def sql_key(sql) "#{schema_search_path}-#{sql}" end # Prepare the statement if it hasn't been prepared, return # the statement key. def prepare_statement(sql) sql_key = sql_key(sql) unless @statements.key? sql_key nextkey = @statements.next_key @connection.prepare nextkey, sql @statements[sql_key] = nextkey end @statements[sql_key] end # The internal PostgreSQL identifier of the money data type. MONEY_COLUMN_TYPE_OID = 790 #:nodoc: # The internal PostgreSQL identifier of the BYTEA data type. BYTEA_COLUMN_TYPE_OID = 17 #: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) # 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. PostgreSQLColumn.money_precision = (postgresql_version >= 80300) ? 19 : 10 configure_connection end # Configures the encoding, verbosity, schema search path, and time zone of the connection. # This is called by #connect and should not be called manually. def configure_connection if @config[:encoding] @connection.set_client_encoding(@config[:encoding]) end self.client_min_messages = @config[:min_messages] if @config[:min_messages] self.schema_search_path = @config[:schema_search_path] || @config[:schema_order] # Use standard-conforming strings if available so we don't have to do the E'...' dance. set_standard_conforming_strings # If using Active Record's time zone support configure the connection to return # TIMESTAMP WITH ZONE types in UTC. if ActiveRecord::Base.default_timezone == :utc execute("SET time zone 'UTC'", 'SCHEMA') elsif @local_tz execute("SET time zone '#{@local_tz}'", 'SCHEMA') end end # Returns the current ID of a table's sequence. def last_insert_id(sequence_name) #:nodoc: r = exec_query("SELECT currval('#{sequence_name}')", 'SQL') Integer(r.rows.first.first) 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, binds = []) exec_query(sql, name, binds).to_a end def select_raw(sql, name = nil) res = execute(sql, name) results = result_as_array(res) fields = res.fields res.clear return fields, results 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: exec_query(<<-end_sql, 'SCHEMA').rows SELECT a.attname, format_type(a.atttypid, a.atttypmod), pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod 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.start_with?('"') ? name.match(/\"([^\"]+)\"/) : name.match(/([^\.]+)/) if match_data rest = name[match_data[0].length, name.length] rest = rest[1, rest.length] if rest.start_with? "." [match_data[1], (rest.length > 0 ? rest : nil)] end end def extract_table_ref_from_insert_sql(sql) sql[/into\s+([^\(]*).*values\s*\(/i] $1.strip if $1 end def table_definition TableDefinition.new(self) end end end end