Module: Sequel::Postgres::DatabaseMethods

Overview

Methods shared by Database instances that connect to PostgreSQL.

Constant Summary

PREPARED_ARG_PLACEHOLDER =
LiteralString.new('$').freeze
RE_CURRVAL_ERROR =
/currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.freeze
FOREIGN_KEY_LIST_ON_DELETE_MAP =
{'a'.freeze=>:no_action, 'r'.freeze=>:restrict, 'c'.freeze=>:cascade, 'n'.freeze=>:set_null, 'd'.freeze=>:set_default}.freeze
POSTGRES_DEFAULT_RE =
/\A(?:B?('.*')::[^']+|\((-?\d+(?:\.\d+)?)\))\z/
UNLOGGED =
'UNLOGGED '.freeze
ON_COMMIT =
{
  :drop => 'DROP', :delete_rows => 'DELETE ROWS', :preserve_rows => 'PRESERVE ROWS',
}.freeze
SELECT_CUSTOM_SEQUENCE_SQL =

SQL fragment for custom sequences (ones not created by serial primary key), Returning the schema and literal form of the sequence name, by parsing the column defaults table.

(<<-end_sql
  SELECT name.nspname AS "schema",
      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 AS "sequence"
  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'
end_sql
).strip.gsub(/\s+/, ' ').freeze
SELECT_PK_SQL =

SQL fragment for determining primary key column for the given table. Only returns the first primary key if the table has a composite primary key.

(<<-end_sql
  SELECT pg_attribute.attname AS pk
  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'
end_sql
).strip.gsub(/\s+/, ' ').freeze
SELECT_SERIAL_SEQUENCE_SQL =

SQL fragment for getting sequence associated with table's primary key, assuming it was a serial primary key column.

(<<-end_sql
  SELECT  name.nspname AS "schema", seq.relname AS "sequence"
  FROM pg_class seq, pg_attribute attr, pg_depend dep,
    pg_namespace name, pg_constraint cons, pg_class t
  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 attr.attrelid = t.oid
    AND cons.contype = 'p'
end_sql
).strip.gsub(/\s+/, ' ').freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Database::ResetIdentifierMangling

extended

Instance Attribute Details

#conversion_procsObject (readonly)

A hash of conversion procs, keyed by type integer (oid) and having callable values for the conversion proc for that type.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 155

def conversion_procs
  @conversion_procs
end

Instance Method Details

#commit_prepared_transaction(transaction_id, opts = OPTS) ⇒ Object

Commit an existing prepared transaction with the given transaction identifier string.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 159

def commit_prepared_transaction(transaction_id, opts=OPTS)
  run("COMMIT PREPARED #{literal(transaction_id)}", opts)
end

#create_function(name, definition, opts = OPTS) ⇒ Object

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.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 183

def create_function(name, definition, opts=OPTS)
  self << create_function_sql(name, definition, opts)
end

#create_language(name, opts = OPTS) ⇒ Object

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.

    • :replace : Replace the installed language if it already exists (on PostgreSQL 9.0+).

    • :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.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 194

def create_language(name, opts=OPTS)
  self << create_language_sql(name, opts)
end

#create_schema(name, opts = OPTS) ⇒ Object

Create a schema in the database. Arguments:

  • name : Name of the schema (e.g. admin)

  • opts : options hash:

    • :if_not_exists : Don't raise an error if the schema already exists (PostgreSQL 9.3+)

    • :owner : The owner to set for the schema (defaults to current user if not specified)



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# File 'lib/sequel/adapters/shared/postgres.rb', line 203

def create_schema(name, opts=OPTS)
  self << create_schema_sql(name, opts)
end

#create_trigger(table, name, function, opts = OPTS) ⇒ Object

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.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 217

def create_trigger(table, name, function, opts=OPTS)
  self << create_trigger_sql(table, name, function, opts)
end

#database_typeObject

PostgreSQL uses the :postgres database type.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 222

def database_type
  :postgres
end

#do(code, opts = OPTS) ⇒ Object

Use PostgreSQL's DO syntax to execute an anonymous code block. The code should be the literal code string to use in the underlying procedural language. Options:

:language

The procedural language the code is written in. The PostgreSQL default is plpgsql. Can be specified as a string or a symbol.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 231

def do(code, opts=OPTS)
  language = opts[:language]
  run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
end

#drop_function(name, opts = OPTS) ⇒ Object

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.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 242

def drop_function(name, opts=OPTS)
  self << drop_function_sql(name, opts)
end

#drop_language(name, opts = OPTS) ⇒ Object

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.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 251

def drop_language(name, opts=OPTS)
  self << drop_language_sql(name, opts)
end

#drop_schema(name, opts = OPTS) ⇒ Object

Drops a schema from the database. Arguments:

  • name : name of the schema to drop

  • opts : options hash:

    • :cascade : Drop all objects in this schema.

    • :if_exists : Don't raise an error if the schema doesn't exist.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 260

def drop_schema(name, opts=OPTS)
  self << drop_schema_sql(name, opts)
end

#drop_trigger(table, name, opts = OPTS) ⇒ Object

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.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 270

def drop_trigger(table, name, opts=OPTS)
  self << drop_trigger_sql(table, name, opts)
end

#foreign_key_list(table, opts = OPTS) ⇒ Object

Return full foreign key information using the pg system tables, including :name, :on_delete, :on_update, and :deferrable entries in the hashes.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 276

def foreign_key_list(table, opts=OPTS)
  m = output_identifier_meth
  schema, _ = opts.fetch(:schema, schema_and_table(table))
  range = 0...32

  base_ds = .
    from(:pg_constraint___co).
    join(:pg_class___cl, :oid=>:conrelid).
    where(:cl__relkind=>'r', :co__contype=>'f', :cl__oid=>regclass_oid(table))

  # We split the parsing into two separate queries, which are merged manually later.
  # This is because PostgreSQL stores both the referencing and referenced columns in
  # arrays, and I don't know a simple way to not create a cross product, as PostgreSQL
  # doesn't appear to have a function that takes an array and element and gives you
  # the index of that element in the array.

  ds = base_ds.
    join(:pg_attribute___att, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__conkey)).
    order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att__attnum)).
    select(:co__conname___name, :att__attname___column, :co__confupdtype___on_update, :co__confdeltype___on_delete,
           SQL::BooleanExpression.new(:AND, :co__condeferrable, :co__condeferred).as(:deferrable))

  ref_ds = base_ds.
    join(:pg_class___cl2, :oid=>:co__confrelid).
    join(:pg_attribute___att2, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__confkey)).
    order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att2__attnum)).
    select(:co__conname___name, :cl2__relname___table, :att2__attname___refcolumn)

  # If a schema is given, we only search in that schema, and the returned :table
  # entry is schema qualified as well.
  if schema
    ref_ds = ref_ds.join(:pg_namespace___nsp2, :oid=>:cl2__relnamespace).
      select_more(:nsp2__nspname___schema)
  end

  h = {}
  fklod_map = FOREIGN_KEY_LIST_ON_DELETE_MAP 
  ds.each do |row|
    if r = h[row[:name]]
      r[:columns] << m.call(row[:column])
    else
      h[row[:name]] = {:name=>m.call(row[:name]), :columns=>[m.call(row[:column])], :on_update=>fklod_map[row[:on_update]], :on_delete=>fklod_map[row[:on_delete]], :deferrable=>row[:deferrable]}
    end
  end
  ref_ds.each do |row|
    r = h[row[:name]]
    r[:table] ||= schema ? SQL::QualifiedIdentifier.new(m.call(row[:schema]), m.call(row[:table])) : m.call(row[:table])
    r[:key] ||= []
    r[:key] << m.call(row[:refcolumn])
  end
  h.values
end

#indexes(table, opts = OPTS) ⇒ Object

Use the pg_* system tables to determine indexes on a table



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# File 'lib/sequel/adapters/shared/postgres.rb', line 330

def indexes(table, opts=OPTS)
  m = output_identifier_meth
  range = 0...32
  attnums = server_version >= 80100 ? SQL::Function.new(:ANY, :ind__indkey) : range.map{|x| SQL::Subscript.new(:ind__indkey, [x])}
  ds = .
    from(:pg_class___tab).
    join(:pg_index___ind, :indrelid=>:oid).
    join(:pg_class___indc, :oid=>:indexrelid).
    join(:pg_attribute___att, :attrelid=>:tab__oid, :attnum=>attnums).
    left_join(:pg_constraint___con, :conname=>:indc__relname).
    filter(:indc__relkind=>'i', :ind__indisprimary=>false, :indexprs=>nil, :indpred=>nil, :indisvalid=>true, :tab__oid=>regclass_oid(table, opts)).
    order(:indc__relname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:ind__indkey, [x]), x]}, 32, :att__attnum)).
    select(:indc__relname___name, :ind__indisunique___unique, :att__attname___column, :con__condeferrable___deferrable)

  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], :deferrable=>r[:deferrable]}
    i[:columns] << m.call(r[:column])
  end
  indexes
end

#locksObject

Dataset containing all current database locks



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# File 'lib/sequel/adapters/shared/postgres.rb', line 355

def locks
  dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks))
end

#notify(channel, opts = OPTS) ⇒ Object

Notifies the given channel. See the PostgreSQL NOTIFY documentation. Options:

:payload

The payload string to use for the NOTIFY statement. Only supported in PostgreSQL 9.0+.

:server

The server to which to send the NOTIFY statement, if the sharding support is being used.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 365

def notify(channel, opts=OPTS)
  sql = "NOTIFY "
  dataset.send(:identifier_append, sql, channel)
  if payload = opts[:payload]
    sql << ", "
    dataset.literal_append(sql, payload.to_s)
  end
  execute_ddl(sql, opts)
end

#primary_key(table, opts = OPTS) ⇒ Object

Return primary key for the given table.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 376

def primary_key(table, opts=OPTS)
  quoted_table = quote_schema_table(table)
  Sequel.synchronize{return @primary_keys[quoted_table] if @primary_keys.has_key?(quoted_table)}
  sql = "#{SELECT_PK_SQL} AND pg_class.oid = #{literal(regclass_oid(table, opts))}"
  value = fetch(sql).single_value
  Sequel.synchronize{@primary_keys[quoted_table] = value}
end

#primary_key_sequence(table, opts = OPTS) ⇒ Object

Return the sequence providing the default for the primary key for the given table.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 385

def primary_key_sequence(table, opts=OPTS)
  quoted_table = quote_schema_table(table)
  Sequel.synchronize{return @primary_key_sequences[quoted_table] if @primary_key_sequences.has_key?(quoted_table)}
  sql = "#{SELECT_SERIAL_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
  if pks = fetch(sql).single_record
    value = literal(SQL::QualifiedIdentifier.new(pks[:schema], pks[:sequence]))
    Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
  else
    sql = "#{SELECT_CUSTOM_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
    if pks = fetch(sql).single_record
      value = literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
      Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
    end
  end
end

#refresh_view(name, opts = OPTS) ⇒ Object

Refresh the materialized view with the given name.

DB.refresh_view(:items_view)
# REFRESH MATERIALIZED VIEW items_view


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# File 'lib/sequel/adapters/shared/postgres.rb', line 405

def refresh_view(name, opts=OPTS)
  run "REFRESH MATERIALIZED VIEW #{quote_schema_table(name)}"
end

#reset_conversion_procsObject

Reset the database's conversion procs, requires a server query if there any named types.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 411

def reset_conversion_procs
  @conversion_procs = get_conversion_procs
end

#reset_primary_key_sequence(table) ⇒ Object

Reset the primary key sequence for the given table, basing it on the maximum current value of the table's primary key.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 417

def reset_primary_key_sequence(table)
  return unless seq = primary_key_sequence(table)
  pk = SQL::Identifier.new(primary_key(table))
  db = self
  seq_ds = db.from(LiteralString.new(seq))
  s, t = schema_and_table(table)
  table = Sequel.qualify(s, t) if s
  get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)}
end

#rollback_prepared_transaction(transaction_id, opts = OPTS) ⇒ Object

Rollback an existing prepared transaction with the given transaction identifier string.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 429

def rollback_prepared_transaction(transaction_id, opts=OPTS)
  run("ROLLBACK PREPARED #{literal(transaction_id)}", opts)
end

#serial_primary_key_optionsObject

PostgreSQL uses SERIAL psuedo-type instead of AUTOINCREMENT for managing incrementing primary keys.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 435

def serial_primary_key_options
  {:primary_key => true, :serial => true, :type=>Integer}
end

#server_version(server = nil) ⇒ Object

The version of the PostgreSQL server, used for determining capability.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 440

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
    @server_version = if m = /PostgreSQL (\d+)\.(\d+)(?:(?:rc\d+)|\.(\d+))?/.match(fetch('SELECT version()').single_value)
      (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
    else
      0
    end
  end
  warn 'Sequel no longer supports PostgreSQL <8.2, some things may not work' if @server_version < 80200
  @server_version
end

#supports_create_table_if_not_exists?Boolean

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+



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# File 'lib/sequel/adapters/shared/postgres.rb', line 457

def supports_create_table_if_not_exists?
  server_version >= 90100
end

#supports_deferrable_constraints?Boolean

PostgreSQL 9.0+ supports some types of deferrable constraints beyond foreign key constraints.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 462

def supports_deferrable_constraints?
  server_version >= 90000
end

#supports_deferrable_foreign_key_constraints?Boolean

PostgreSQL supports deferrable foreign key constraints.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 467

def supports_deferrable_foreign_key_constraints?
  true
end

#supports_drop_table_if_exists?Boolean

PostgreSQL supports DROP TABLE IF EXISTS



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# File 'lib/sequel/adapters/shared/postgres.rb', line 472

def supports_drop_table_if_exists?
  true
end

#supports_partial_indexes?Boolean

PostgreSQL supports partial indexes.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 477

def supports_partial_indexes?
  true
end

#supports_prepared_transactions?Boolean

PostgreSQL supports prepared transactions (two-phase commit) if max_prepared_transactions is greater than 0.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 483

def supports_prepared_transactions?
  return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
  @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
end

#supports_savepoints?Boolean

PostgreSQL supports savepoints



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# File 'lib/sequel/adapters/shared/postgres.rb', line 489

def supports_savepoints?
  true
end

#supports_transaction_isolation_levels?Boolean

PostgreSQL supports transaction isolation levels



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# File 'lib/sequel/adapters/shared/postgres.rb', line 494

def supports_transaction_isolation_levels?
  true
end

#supports_transactional_ddl?Boolean

PostgreSQL supports transaction DDL statements.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 499

def supports_transactional_ddl?
  true
end

#tables(opts = OPTS, &block) ⇒ Object

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:

:qualify

Return the tables as Sequel::SQL::QualifiedIdentifier instances, using the schema the table is located in as the qualifier.

:schema

The schema to search

:server

The server to use



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# File 'lib/sequel/adapters/shared/postgres.rb', line 512

def tables(opts=OPTS, &block)
  pg_class_relname('r', opts, &block)
end

#type_supported?(type) ⇒ Boolean

Check whether the given type name string/symbol (e.g. :hstore) is supported by the database.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 518

def type_supported?(type)
  @supported_types ||= {}
  @supported_types.fetch(type){@supported_types[type] = (from(:pg_type).filter(:typtype=>'b', :typname=>type.to_s).count > 0)}
end

#views(opts = OPTS) ⇒ Object

Array of symbols specifying view names in the current database.

Options:

:qualify

Return the views as Sequel::SQL::QualifiedIdentifier instances, using the schema the view is located in as the qualifier.

:schema

The schema to search

:server

The server to use



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# File 'lib/sequel/adapters/shared/postgres.rb', line 530

def views(opts=OPTS)
  pg_class_relname('v', opts)
end