Module: Sequel::Postgres::DatasetMethods

Included in:
DataObjects::Postgres::Dataset, JDBC::Postgres::Dataset, Dataset
Defined in:
lib/sequel/adapters/shared/postgres.rb

Overview

Instance methods for datasets that connect to a PostgreSQL database.

Defined Under Namespace

Modules: PreparedStatementMethods

Constant Summary collapse

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')

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.extended(obj) ⇒ Object

Add the disable_insert_returning! mutation method



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# File 'lib/sequel/adapters/shared/postgres.rb', line 663

def self.extended(obj)
  obj.def_mutation_method(:disable_insert_returning)
end

.included(mod) ⇒ Object

Add the disable_insert_returning! mutation method



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# File 'lib/sequel/adapters/shared/postgres.rb', line 668

def self.included(mod)
  mod.def_mutation_method(:disable_insert_returning)
end

Instance Method Details

#analyze ⇒ Object

Return the results of an ANALYZE query as a string



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# File 'lib/sequel/adapters/shared/postgres.rb', line 673

def analyze
  explain(:analyze=>true)
end

#complex_expression_sql(op, args) ⇒ Object

Handle converting the ruby xor operator (^) into the PostgreSQL xor operator (#).



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# File 'lib/sequel/adapters/shared/postgres.rb', line 679

def complex_expression_sql(op, args)
  case op
  when :^
    "(#{literal(args.at(0))} # #{literal(args.at(1))})"
  else
    super
  end
end

#disable_insert_returning ⇒ Object

Disable the use of INSERT RETURNING, even if the server supports it



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# File 'lib/sequel/adapters/shared/postgres.rb', line 689

def disable_insert_returning
  clone(:disable_insert_returning=>true)
end

#explain(opts = {}) ⇒ Object

Return the results of an EXPLAIN query as a string



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# File 'lib/sequel/adapters/shared/postgres.rb', line 694

def explain(opts={})
  with_sql((opts[:analyze] ? EXPLAIN_ANALYZE : EXPLAIN) + select_sql).map(QUERY_PLAN).join("\r\n")
end

#for_share ⇒ Object

Return a cloned dataset which will use FOR SHARE to lock returned rows.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 699

def for_share
  lock_style(:share)
end

#full_text_search(cols, terms, opts = {}) ⇒ Object

PostgreSQL specific full text search syntax, using tsearch2 (included in 8.3 by default, and available for earlier versions as an add-on).



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# File 'lib/sequel/adapters/shared/postgres.rb', line 705

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(*values) ⇒ Object

Insert given values into the database.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 711

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

#insert_returning_sql(returning, *values) ⇒ Object

Use the RETURNING clause to return the columns listed in returning.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 722

def insert_returning_sql(returning, *values)
  "#{insert_sql(*values)} RETURNING #{column_list(Array(returning))}"
end

#insert_select(*values) ⇒ Object

Insert a record returning the record inserted



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# File 'lib/sequel/adapters/shared/postgres.rb', line 727

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

#lock(mode, opts = {}) ⇒ Object

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.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 737

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

#multi_insert_sql(columns, values) ⇒ Object

For PostgreSQL version > 8.2, allow inserting multiple rows at once.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 747

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

#supports_distinct_on? ⇒ Boolean

DISTINCT ON is a PostgreSQL extension

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 755

def supports_distinct_on?
  true
end

#supports_modifying_joins? ⇒ Boolean

PostgreSQL supports modifying joined datasets

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 760

def supports_modifying_joins?
  true
end

#supports_timestamp_timezones? ⇒ Boolean

PostgreSQL supports timezones in literal timestamps

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 765

def supports_timestamp_timezones?
  true
end

#supports_window_functions? ⇒ Boolean

PostgreSQL 8.4+ supports window functions

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 770

def supports_window_functions?
  server_version >= 80400
end

#window(name, opts) ⇒ Object

Return a clone of the dataset with an addition named window that can be referenced in window functions.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 775

def window(name, opts)
  clone(:window=>(@opts[:window]||[]) + [[name, SQL::Window.new(opts)]])
end