module Sequel
Dataset::NON_SQL_OPTIONS << :disable_insert_returning
# Top level module for holding all PostgreSQL-related modules and classes
# for Sequel. There are a few module level accessors that are added via
# metaprogramming. These are:
# * client_min_messages (only available when using the native adapter) -
# Change the minimum level of messages that PostgreSQL will send to the
# the client. The PostgreSQL default is NOTICE, the Sequel default is
# WARNING. Set to nil to not change the server default.
# * force_standard_strings - Set to false to not force the use of
# standard strings
# * use_iso_date_format (only available when using the native adapter) -
# Set to false to not change the date format to
# ISO. This disables one of Sequel's optimizations.
#
# Changes in these settings only affect future connections. To make
# sure that they are applied, they should generally be called right
# after the Database object is instantiated and before a connection
# is actually made. For example, to use whatever the server defaults are:
#
# DB = Sequel.postgres(...)
# Sequel::Postgres.client_min_messages = nil
# Sequel::Postgres.force_standard_strings = false
# Sequel::Postgres.use_iso_date_format = false
# # A connection to the server is not made until here
# DB[:t].all
#
# The reason they can't be done earlier is that the Sequel::Postgres
# module is not loaded until a Database object which uses PostgreSQL
# is created.
module Postgres
# Array of exceptions that need to be converted. JDBC
# uses NativeExceptions, the native adapter uses PGError.
CONVERTED_EXCEPTIONS = []
@client_min_messages = :warning
@force_standard_strings = true
class << self
# By default, Sequel sets the minimum level of log messages sent to the client
# to WARNING, where PostgreSQL uses a default of NOTICE. This is to avoid a lot
# of mostly useless messages when running migrations, such as a couple of lines
# for every serial primary key field.
attr_accessor :client_min_messages
# By default, Sequel forces the use of standard strings, so that
# '\\' is interpreted as \\ and not \. While PostgreSQL defaults
# to interpreting plain strings as extended strings, this will change
# in a future version of PostgreSQL. Sequel assumes that SQL standard
# strings will be used.
attr_accessor :force_standard_strings
end
# Methods shared by adapter/connection instances.
module AdapterMethods
attr_writer :db
SELECT_CURRVAL = "SELECT currval('%s')".freeze
SELECT_CUSTOM_SEQUENCE = proc do |schema, table| <<-end_sql
SELECT '"' || name.nspname || '".' || 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_namespace name ON (t.relnamespace = name.oid)
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 cons.contype = 'p'
AND def.adsrc ~* 'nextval'
#{"AND name.nspname = '#{schema}'" if schema}
AND t.relname = '#{table}'
end_sql
end
SELECT_PK = proc do |schema, table| <<-end_sql
SELECT pg_attribute.attname
FROM pg_class, pg_attribute, pg_index, pg_namespace
WHERE pg_class.oid = pg_attribute.attrelid
AND pg_class.relnamespace = pg_namespace.oid
AND pg_class.oid = pg_index.indrelid
AND pg_index.indkey[0] = pg_attribute.attnum
AND pg_index.indisprimary = 't'
#{"AND pg_namespace.nspname = '#{schema}'" if schema}
AND pg_class.relname = '#{table}'
end_sql
end
SELECT_SERIAL_SEQUENCE = proc do |schema, table| <<-end_sql
SELECT '"' || name.nspname || '".' || 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.relnamespace = name.oid
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 name.nspname = '#{schema}'" if schema}
AND seq.relname = '#{table}'
end_sql
end
# Depth of the current transaction on this connection, used
# to implement multi-level transactions with savepoints.
attr_accessor :transaction_depth
# Apply connection settings for this connection. Currently, turns
# standard_conforming_strings ON if Postgres.force_standard_strings
# is true.
def apply_connection_settings
if Postgres.force_standard_strings
sql = "SET standard_conforming_strings = ON"
@db.log_info(sql)
# This setting will only work on PostgreSQL 8.2 or greater
# and we don't know the server version at this point, so
# try it unconditionally and rescue any errors.
execute(sql) rescue nil
end
if cmm = Postgres.client_min_messages
sql = "SET client_min_messages = '#{cmm.to_s.upcase}'"
@db.log_info(sql)
execute(sql)
end
end
# Get the last inserted value for the given sequence.
def last_insert_id(sequence)
sql = SELECT_CURRVAL % sequence
@db.log_info(sql)
execute(sql) do |r|
val = single_value(r)
return val.to_i if val
end
end
# Get the primary key for the given table.
def primary_key(schema, table)
sql = SELECT_PK[schema, table]
@db.log_info(sql)
execute(sql) do |r|
return single_value(r)
end
end
# Get the primary key and sequence for the given table.
def sequence(schema, table)
sql = SELECT_SERIAL_SEQUENCE[schema, table]
@db.log_info(sql)
execute(sql) do |r|
seq = single_value(r)
return seq if seq
end
sql = SELECT_CUSTOM_SEQUENCE[schema, table]
@db.log_info(sql)
execute(sql) do |r|
return single_value(r)
end
end
end
# Methods shared by Database instances that connect to PostgreSQL.
module DatabaseMethods
PREPARED_ARG_PLACEHOLDER = LiteralString.new('$').freeze
RE_CURRVAL_ERROR = /currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.freeze
SYSTEM_TABLE_REGEXP = /^pg|sql/.freeze
# Creates the function in the database. Arguments:
# * name : name of the function to create
# * definition : string definition of the function, or object file for a dynamically loaded C function.
# * opts : options hash:
# * :args : function arguments, can be either a symbol or string specifying a type or an array of 1-3 elements:
# * element 1 : argument data type
# * element 2 : argument name
# * element 3 : argument mode (e.g. in, out, inout)
# * :behavior : Should be IMMUTABLE, STABLE, or VOLATILE. PostgreSQL assumes VOLATILE by default.
# * :cost : The estimated cost of the function, used by the query planner.
# * :language : The language the function uses. SQL is the default.
# * :link_symbol : For a dynamically loaded see function, the function's link symbol if different from the definition argument.
# * :returns : The data type returned by the function. If you are using OUT or INOUT argument modes, this is ignored.
# Otherwise, if this is not specified, void is used by default to specify the function is not supposed to return a value.
# * :rows : The estimated number of rows the function will return. Only use if the function returns SETOF something.
# * :security_definer : Makes the privileges of the function the same as the privileges of the user who defined the function instead of
# the privileges of the user who runs the function. There are security implications when doing this, see the PostgreSQL documentation.
# * :set : Configuration variables to set while the function is being run, can be a hash or an array of two pairs. search_path is
# often used here if :security_definer is used.
# * :strict : Makes the function return NULL when any argument is NULL.
def create_function(name, definition, opts={})
self << create_function_sql(name, definition, opts)
end
# Create the procedural language in the database. Arguments:
# * name : Name of the procedural language (e.g. plpgsql)
# * opts : options hash:
# * :handler : The name of a previously registered function used as a call handler for this language.
# * :trusted : Marks the language being created as trusted, allowing unprivileged users to create functions using this language.
# * :validator : The name of previously registered function used as a validator of functions defined in this language.
def create_language(name, opts={})
self << create_language_sql(name, opts)
end
# Create a trigger in the database. Arguments:
# * table : the table on which this trigger operates
# * name : the name of this trigger
# * function : the function to call for this trigger, which should return type trigger.
# * opts : options hash:
# * :after : Calls the trigger after execution instead of before.
# * :args : An argument or array of arguments to pass to the function.
# * :each_row : Calls the trigger for each row instead of for each statement.
# * :events : Can be :insert, :update, :delete, or an array of any of those. Calls the trigger whenever that type of statement is used. By default,
# the trigger is called for insert, update, or delete.
def create_trigger(table, name, function, opts={})
self << create_trigger_sql(table, name, function, opts)
end
# PostgreSQL uses the :postgres database type.
def database_type
:postgres
end
# Drops the function from the database. Arguments:
# * name : name of the function to drop
# * opts : options hash:
# * :args : The arguments for the function. See create_function_sql.
# * :cascade : Drop other objects depending on this function.
# * :if_exists : Don't raise an error if the function doesn't exist.
def drop_function(name, opts={})
self << drop_function_sql(name, opts)
end
# Drops a procedural language from the database. Arguments:
# * name : name of the procedural language to drop
# * opts : options hash:
# * :cascade : Drop other objects depending on this function.
# * :if_exists : Don't raise an error if the function doesn't exist.
def drop_language(name, opts={})
self << drop_language_sql(name, opts)
end
# Remove the cached entries for primary keys and sequences when dropping a table.
def drop_table(*names)
names.each do |name|
name = quote_schema_table(name)
@primary_keys.delete(name)
@primary_key_sequences.delete(name)
end
super
end
# Drops a trigger from the database. Arguments:
# * table : table from which to drop the trigger
# * name : name of the trigger to drop
# * opts : options hash:
# * :cascade : Drop other objects depending on this function.
# * :if_exists : Don't raise an error if the function doesn't exist.
def drop_trigger(table, name, opts={})
self << drop_trigger_sql(table, name, opts)
end
# Return a hash containing index information. Hash keys are index name symbols.
# Values are subhashes with two keys, :columns and :unique. The value of :columns
# is an array of symbols of column names. The value of :unique is true or false
# depending on if the index is unique.
#
# This will not output any partial indexes, indexes that aren't valid or ready,
# or indexes that contain anything other than simple column references.
def indexes(table)
m = output_identifier_meth
im = input_identifier_meth
schema, table = schema_and_table(table)
range = 0...32
attnums = server_version >= 80100 ? SQL::Function.new(:ANY, :ind__indkey) : range.map{|x| SQL::Subscript.new(:ind__indkey, [x])}
ds = metadata_dataset.
from(:pg_class___tab).
join(:pg_index___ind, :indrelid=>:oid, im.call(table)=>:relname).
join(:pg_class___indc, :oid=>:indexrelid).
join(:pg_attribute___att, :attrelid=>:tab__oid, :attnum=>attnums).
filter(:indc__relkind=>'i', :ind__indisprimary=>false, :indexprs=>nil, :indpred=>nil).
order(:indc__relname, range.map{|x| [SQL::Subscript.new(:ind__indkey, [x]), x]}.case(32, :att__attnum)).
select(:indc__relname___name, :ind__indisunique___unique, :att__attname___column)
ds.join!(:pg_namespace___nsp, :oid=>:tab__relnamespace, :nspname=>schema.to_s) if schema
ds.filter!(:indisvalid=>true) if server_version >= 80200
ds.filter!(:indisready=>true, :indcheckxmin=>false) if server_version >= 80300
indexes = {}
ds.each do |r|
i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique]}
i[:columns] << m.call(r[:column])
end
indexes
end
# Dataset containing all current database locks
def locks
dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks))
end
# Return primary key for the given table.
def primary_key(table, opts={})
quoted_table = quote_schema_table(table)
return @primary_keys[quoted_table] if @primary_keys.include?(quoted_table)
@primary_keys[quoted_table] = if conn = opts[:conn]
conn.primary_key(*schema_and_table(table))
else
synchronize(opts[:server]){|con| con.primary_key(*schema_and_table(table))}
end
end
# Return the sequence providing the default for the primary key for the given table.
def primary_key_sequence(table, opts={})
quoted_table = quote_schema_table(table)
return @primary_key_sequences[quoted_table] if @primary_key_sequences.include?(quoted_table)
@primary_key_sequences[quoted_table] = if conn = opts[:conn]
conn.sequence(*schema_and_table(table))
else
synchronize(opts[:server]){|con| con.sequence(*schema_and_table(table))}
end
end
# Reset the primary key sequence for the given table, baseing it on the
# maximum current value of the table's primary key.
def reset_primary_key_sequence(table)
pk = SQL::Identifier.new(primary_key(table))
return unless seq = primary_key_sequence(table)
db = self
seq_ds = db.from(seq.lit)
get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)}
end
# PostgreSQL uses SERIAL psuedo-type instead of AUTOINCREMENT for
# managing incrementing primary keys.
def serial_primary_key_options
{:primary_key => true, :serial => true, :type=>Integer}
end
# The version of the PostgreSQL server, used for determining capability.
def server_version(server=nil)
return @server_version if @server_version
@server_version = synchronize(server) do |conn|
(conn.server_version rescue nil) if conn.respond_to?(:server_version)
end
unless @server_version
m = /PostgreSQL (\d+)\.(\d+)(?:(?:rc\d+)|\.(\d+))?/.match(fetch('SELECT version()').single_value)
@server_version = (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
end
@server_version
end
# PostgreSQL supports savepoints
def supports_savepoints?
true
end
# Whether the given table exists in the database
#
# Options:
# * :schema - The schema to search (default_schema by default)
# * :server - The server to use
def table_exists?(table, opts={})
im = input_identifier_meth
schema, table = schema_and_table(table)
opts[:schema] ||= schema
tables(opts){|ds| !ds.first(:relname=>im.call(table)).nil?}
end
# Array of symbols specifying table names in the current database.
# The dataset used is yielded to the block if one is provided,
# otherwise, an array of symbols of table names is returned.
#
# Options:
# * :schema - The schema to search (default_schema by default)
# * :server - The server to use
def tables(opts={})
ds = metadata_dataset.from(:pg_class).filter(:relkind=>'r').select(:relname).exclude(SQL::StringExpression.like(:relname, SYSTEM_TABLE_REGEXP)).server(opts[:server]).join(:pg_namespace, :oid=>:relnamespace, :nspname=>(opts[:schema]||default_schema||'public').to_s)
m = output_identifier_meth
block_given? ? yield(ds) : ds.map{|r| m.call(r[:relname])}
end
private
# SQL statement to create database function.
def create_function_sql(name, definition, opts={})
args = opts[:args]
if !opts[:args].is_a?(Array) || !opts[:args].any?{|a| Array(a).length == 3 and %w'OUT INOUT'.include?(a[2].to_s)}
returns = opts[:returns] || 'void'
end
language = opts[:language] || 'SQL'
<<-END
CREATE#{' OR REPLACE' if opts[:replace]} FUNCTION #{name}#{sql_function_args(args)}
#{"RETURNS #{returns}" if returns}
LANGUAGE #{language}
#{opts[:behavior].to_s.upcase if opts[:behavior]}
#{'STRICT' if opts[:strict]}
#{'SECURITY DEFINER' if opts[:security_definer]}
#{"COST #{opts[:cost]}" if opts[:cost]}
#{"ROWS #{opts[:rows]}" if opts[:rows]}
#{opts[:set].map{|k,v| " SET #{k} = #{v}"}.join("\n") if opts[:set]}
AS #{literal(definition.to_s)}#{", #{literal(opts[:link_symbol].to_s)}" if opts[:link_symbol]}
END
end
# SQL for creating a procedural language.
def create_language_sql(name, opts={})
"CREATE#{' TRUSTED' if opts[:trusted]} LANGUAGE #{name}#{" HANDLER #{opts[:handler]}" if opts[:handler]}#{" VALIDATOR #{opts[:validator]}" if opts[:validator]}"
end
# SQL for creating a database trigger.
def create_trigger_sql(table, name, function, opts={})
events = opts[:events] ? Array(opts[:events]) : [:insert, :update, :delete]
whence = opts[:after] ? 'AFTER' : 'BEFORE'
"CREATE TRIGGER #{name} #{whence} #{events.map{|e| e.to_s.upcase}.join(' OR ')} ON #{quote_schema_table(table)}#{' FOR EACH ROW' if opts[:each_row]} EXECUTE PROCEDURE #{function}(#{Array(opts[:args]).map{|a| literal(a)}.join(', ')})"
end
# The errors that the main adapters can raise, depends on the adapter being used
def database_error_classes
CONVERTED_EXCEPTIONS
end
# SQL for dropping a function from the database.
def drop_function_sql(name, opts={})
"DROP FUNCTION#{' IF EXISTS' if opts[:if_exists]} #{name}#{sql_function_args(opts[:args])}#{' CASCADE' if opts[:cascade]}"
end
# SQL for dropping a procedural language from the database.
def drop_language_sql(name, opts={})
"DROP LANGUAGE#{' IF EXISTS' if opts[:if_exists]} #{name}#{' CASCADE' if opts[:cascade]}"
end
# Always CASCADE the table drop
def drop_table_sql(name)
"DROP TABLE #{quote_schema_table(name)} CASCADE"
end
# SQL for dropping a trigger from the database.
def drop_trigger_sql(table, name, opts={})
"DROP TRIGGER#{' IF EXISTS' if opts[:if_exists]} #{name} ON #{quote_schema_table(table)}#{' CASCADE' if opts[:cascade]}"
end
# PostgreSQL folds unquoted identifiers to lowercase, so it shouldn't need to upcase identifiers on input.
def identifier_input_method_default
nil
end
# PostgreSQL folds unquoted identifiers to lowercase, so it shouldn't need to upcase identifiers on output.
def identifier_output_method_default
nil
end
# PostgreSQL specific index SQL.
def index_definition_sql(table_name, index)
cols = index[:columns]
index_name = index[:name] || default_index_name(table_name, cols)
expr = if o = index[:opclass]
"(#{Array(cols).map{|c| "#{literal(c)} #{o}"}.join(', ')})"
else
literal(Array(cols))
end
unique = "UNIQUE " if index[:unique]
index_type = index[:type]
filter = index[:where] || index[:filter]
filter = " WHERE #{filter_expr(filter)}" if filter
case index_type
when :full_text
expr = "(to_tsvector(#{literal(index[:language] || 'simple')}, #{dataset.send(:full_text_string_join, cols)}))"
index_type = :gin
when :spatial
index_type = :gist
end
"CREATE #{unique}INDEX #{quote_identifier(index_name)} ON #{quote_schema_table(table_name)} #{"USING #{index_type} " if index_type}#{expr}#{filter}"
end
# The result of the insert for the given table and values. If values
# is an array, assume the first column is the primary key and return
# that. If values is a hash, lookup the primary key for the table. If
# the primary key is present in the hash, return its value. Otherwise,
# look up the sequence for the table's primary key. If one exists,
# return the last value the of the sequence for the connection.
def insert_result(conn, table, values)
case values
when Hash
return nil unless pk = primary_key(table, :conn=>conn)
if pk and pkv = values[pk.to_sym]
pkv
else
begin
if seq = primary_key_sequence(table, :conn=>conn)
conn.last_insert_id(seq)
end
rescue Exception => e
raise_error(e, :classes=>CONVERTED_EXCEPTIONS) unless RE_CURRVAL_ERROR.match(e.message)
end
end
when Array
values.first
else
nil
end
end
# Use a dollar sign instead of question mark for the argument
# placeholder.
def prepared_arg_placeholder
PREPARED_ARG_PLACEHOLDER
end
# SQL DDL statement for renaming a table. PostgreSQL doesn't allow you to change a table's schema in
# a rename table operation, so speciying a new schema in new_name will not have an effect.
def rename_table_sql(name, new_name)
"ALTER TABLE #{quote_schema_table(name)} RENAME TO #{quote_identifier(schema_and_table(new_name).last)}"
end
# PostgreSQL's autoincrementing primary keys are of type integer or bigint
# using a nextval function call as a default.
def schema_autoincrementing_primary_key?(schema)
super and schema[:db_type] =~ /\A(?:integer|bigint)\z/io and schema[:default]=~/\Anextval/io
end
# The dataset used for parsing table schemas, using the pg_* system catalogs.
def schema_parse_table(table_name, opts)
m = output_identifier_meth
m2 = input_identifier_meth
ds = metadata_dataset.select(:pg_attribute__attname___name,
SQL::Function.new(:format_type, :pg_type__oid, :pg_attribute__atttypmod).as(:db_type),
SQL::Function.new(:pg_get_expr, :pg_attrdef__adbin, :pg_class__oid).as(:default),
SQL::BooleanExpression.new(:NOT, :pg_attribute__attnotnull).as(:allow_null),
SQL::Function.new(:COALESCE, SQL::BooleanExpression.from_value_pairs(:pg_attribute__attnum => SQL::Function.new(:ANY, :pg_index__indkey)), false).as(:primary_key)).
from(:pg_class).
join(:pg_attribute, :attrelid=>:oid).
join(:pg_type, :oid=>:atttypid).
left_outer_join(:pg_attrdef, :adrelid=>:pg_class__oid, :adnum=>:pg_attribute__attnum).
left_outer_join(:pg_index, :indrelid=>:pg_class__oid, :indisprimary=>true).
filter(:pg_attribute__attisdropped=>false).
filter{|o| o.pg_attribute__attnum > 0}.
filter(:pg_class__relname=>m2.call(table_name)).
order(:pg_attribute__attnum)
ds.join!(:pg_namespace, :oid=>:pg_class__relnamespace, :nspname=>(opts[:schema] || default_schema).to_s) if opts[:schema] || default_schema
ds.map do |row|
row[:default] = nil if blank_object?(row[:default])
row[:type] = schema_column_type(row[:db_type])
[m.call(row.delete(:name)), row]
end
end
# Turns an array of argument specifiers into an SQL fragment used for function arguments. See create_function_sql.
def sql_function_args(args)
"(#{Array(args).map{|a| Array(a).reverse.join(' ')}.join(', ')})"
end
# Handle bigserial type if :serial option is present
def type_literal_generic_bignum(column)
column[:serial] ? :bigserial : super
end
# PostgreSQL uses the bytea data type for blobs
def type_literal_generic_file(column)
:bytea
end
# Handle serial type if :serial option is present
def type_literal_generic_integer(column)
column[:serial] ? :serial : super
end
# PostgreSQL prefers the text datatype. If a fixed size is requested,
# the char type is used. If the text type is specifically
# disallowed or there is a size specified, use the varchar type.
# Otherwise use the type type.
def type_literal_generic_string(column)
if column[:fixed]
"char(#{column[:size]||255})"
elsif column[:text] == false or column[:size]
"varchar(#{column[:size]||255})"
else
:text
end
end
end
# Instance methods for datasets that connect to a PostgreSQL database.
module DatasetMethods
ACCESS_SHARE = 'ACCESS SHARE'.freeze
ACCESS_EXCLUSIVE = 'ACCESS EXCLUSIVE'.freeze
BOOL_FALSE = 'false'.freeze
BOOL_TRUE = 'true'.freeze
COMMA_SEPARATOR = ', '.freeze
DELETE_CLAUSE_METHODS = Dataset.clause_methods(:delete, %w'from using where')
EXCLUSIVE = 'EXCLUSIVE'.freeze
EXPLAIN = 'EXPLAIN '.freeze
EXPLAIN_ANALYZE = 'EXPLAIN ANALYZE '.freeze
FOR_SHARE = ' FOR SHARE'.freeze
LOCK = 'LOCK TABLE %s IN %s MODE'.freeze
NULL = LiteralString.new('NULL').freeze
PG_TIMESTAMP_FORMAT = "TIMESTAMP '%Y-%m-%d %H:%M:%S".freeze
QUERY_PLAN = 'QUERY PLAN'.to_sym
ROW_EXCLUSIVE = 'ROW EXCLUSIVE'.freeze
ROW_SHARE = 'ROW SHARE'.freeze
SELECT_CLAUSE_METHODS = Dataset.clause_methods(:select, %w'distinct columns from join where group having compounds order limit lock')
SELECT_CLAUSE_METHODS_84 = Dataset.clause_methods(:select, %w'with distinct columns from join where group having window compounds order limit lock')
SHARE = 'SHARE'.freeze
SHARE_ROW_EXCLUSIVE = 'SHARE ROW EXCLUSIVE'.freeze
SHARE_UPDATE_EXCLUSIVE = 'SHARE UPDATE EXCLUSIVE'.freeze
SQL_WITH_RECURSIVE = "WITH RECURSIVE ".freeze
UPDATE_CLAUSE_METHODS = Dataset.clause_methods(:update, %w'table set from where')
# Shared methods for prepared statements when used with PostgreSQL databases.
module PreparedStatementMethods
# Override insert action to use RETURNING if the server supports it.
def prepared_sql
return @prepared_sql if @prepared_sql
super
if @prepared_type == :insert and !@opts[:disable_insert_returning] and server_version >= 80200
@prepared_sql = insert_returning_pk_sql(*@prepared_modify_values)
meta_def(:insert_returning_pk_sql){|*args| prepared_sql}
end
@prepared_sql
end
end
# Add the disable_insert_returning! mutation method
def self.extended(obj)
obj.def_mutation_method(:disable_insert_returning)
end
# Add the disable_insert_returning! mutation method
def self.included(mod)
mod.def_mutation_method(:disable_insert_returning)
end
# Return the results of an ANALYZE query as a string
def analyze
explain(:analyze=>true)
end
# Disable the use of INSERT RETURNING, even if the server supports it
def disable_insert_returning
clone(:disable_insert_returning=>true)
end
# Return the results of an EXPLAIN query as a string
def explain(opts={})
with_sql((opts[:analyze] ? EXPLAIN_ANALYZE : EXPLAIN) + select_sql).map(QUERY_PLAN).join("\r\n")
end
# Return a cloned dataset which will use FOR SHARE to lock returned rows.
def for_share
lock_style(:share)
end
# PostgreSQL specific full text search syntax, using tsearch2 (included
# in 8.3 by default, and available for earlier versions as an add-on).
def full_text_search(cols, terms, opts = {})
lang = opts[:language] || 'simple'
filter("to_tsvector(#{literal(lang)}, #{full_text_string_join(cols)}) @@ to_tsquery(#{literal(lang)}, #{literal(Array(terms).join(' | '))})")
end
# Insert given values into the database.
def insert(*values)
if @opts[:sql]
execute_insert(insert_sql(*values))
elsif @opts[:disable_insert_returning] || server_version < 80200
execute_insert(insert_sql(*values), :table=>opts[:from].first, :values=>values.size == 1 ? values.first : values)
else
clone(default_server_opts(:sql=>insert_returning_pk_sql(*values))).single_value
end
end
# Use the RETURNING clause to return the columns listed in returning.
def insert_returning_sql(returning, *values)
"#{insert_sql(*values)} RETURNING #{column_list(Array(returning))}"
end
# Insert a record returning the record inserted
def insert_select(*values)
return if opts[:disable_insert_returning] || server_version < 80200
naked.clone(default_server_opts(:sql=>insert_returning_sql(nil, *values))).single_record
end
# Locks all tables in the dataset's FROM clause (but not in JOINs) with
# the specified mode (e.g. 'EXCLUSIVE'). If a block is given, starts
# a new transaction, locks the table, and yields. If a block is not given
# just locks the tables. Note that PostgreSQL will probably raise an error
# if you lock the table outside of an existing transaction. Returns nil.
def lock(mode, opts={})
if block_given? # perform locking inside a transaction and yield to block
@db.transaction(opts){lock(mode, opts); yield}
else
@db.execute(LOCK % [source_list(@opts[:from]), mode], opts) # lock without a transaction
end
nil
end
# For PostgreSQL version > 8.2, allow inserting multiple rows at once.
def multi_insert_sql(columns, values)
return super if server_version < 80200
# postgresql 8.2 introduces support for multi-row insert
[insert_sql(columns, LiteralString.new('VALUES ' + values.map {|r| literal(Array(r))}.join(COMMA_SEPARATOR)))]
end
# PostgreSQL supports modifying joined datasets
def supports_modifying_joins?
true
end
# PostgreSQL supports timezones in literal timestamps
def supports_timestamp_timezones?
true
end
# PostgreSQL 8.4+ supports window functions
def supports_window_functions?
server_version >= 80400
end
# Return a clone of the dataset with an addition named window that can be referenced in window functions.
def window(name, opts)
clone(:window=>(@opts[:window]||[]) + [[name, SQL::Window.new(opts)]])
end
private
# PostgreSQL allows deleting from joined datasets
def delete_clause_methods
DELETE_CLAUSE_METHODS
end
# Only include the primary table in the main delete clause
def delete_from_sql(sql)
sql << " FROM #{source_list(@opts[:from][0..0])}"
end
# Use USING to specify additional tables in a delete query
def delete_using_sql(sql)
join_from_sql(:USING, sql)
end
# Use the RETURNING clause to return the primary key of the inserted record, if it exists
def insert_returning_pk_sql(*values)
pk = db.primary_key(opts[:from].first) if opts[:from] && !opts[:from].empty?
insert_returning_sql(pk ? Sequel::SQL::Identifier.new(pk) : NULL, *values)
end
# For multiple table support, PostgreSQL requires at least
# two from tables, with joins allowed.
def join_from_sql(type, sql)
if(from = @opts[:from][1..-1]).empty?
raise(Error, 'Need multiple FROM tables if updating/deleting a dataset with JOINs') if @opts[:join]
else
sql << " #{type} #{source_list(from)}"
select_join_sql(sql)
end
end
# Use a generic blob quoting method, hopefully overridden in one of the subadapter methods
def literal_blob(v)
"'#{v.gsub(/[\000-\037\047\134\177-\377]/){|b| "\\#{("%o" % b[0..1].unpack("C")[0]).rjust(3, '0')}"}}'"
end
# PostgreSQL uses FALSE for false values
def literal_false
BOOL_FALSE
end
# Assume that SQL standard quoting is on, per Sequel's defaults
def literal_string(v)
"'#{v.gsub("'", "''")}'"
end
# PostgreSQL uses FALSE for false values
def literal_true
BOOL_TRUE
end
# The order of clauses in the SELECT SQL statement
def select_clause_methods
server_version >= 80400 ? SELECT_CLAUSE_METHODS_84 : SELECT_CLAUSE_METHODS
end
# Support FOR SHARE locking when using the :share lock style.
def select_lock_sql(sql)
@opts[:lock] == :share ? (sql << FOR_SHARE) : super
end
# SQL fragment for named window specifications
def select_window_sql(sql)
sql << " WINDOW #{@opts[:window].map{|name, window| "#{literal(name)} AS #{literal(window)}"}.join(', ')}" if @opts[:window]
end
# Use WITH RECURSIVE instead of WITH if any of the CTEs is recursive
def select_with_sql_base
opts[:with].any?{|w| w[:recursive]} ? SQL_WITH_RECURSIVE : super
end
# The version of the database server
def server_version
db.server_version(@opts[:server])
end
# Concatenate the expressions with a space in between
def full_text_string_join(cols)
cols = Array(cols).map{|x| SQL::Function.new(:COALESCE, x, '')}
cols = cols.zip([' '] * cols.length).flatten
cols.pop
literal(SQL::StringExpression.new(:'||', *cols))
end
# PostgreSQL splits the main table from the joined tables
def update_clause_methods
UPDATE_CLAUSE_METHODS
end
# Use FROM to specify additional tables in an update query
def update_from_sql(sql)
join_from_sql(:FROM, sql)
end
# Only include the primary table in the main update clause
def update_table_sql(sql)
sql << " #{source_list(@opts[:from][0..0])}"
end
end
end
end