Module: Sequel::Postgres::DatasetMethods

Included in:
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'delete from using where returning')
DELETE_CLAUSE_METHODS_91 = 
Dataset.clause_methods(:delete, %w'with delete from using where returning')
EXCLUSIVE = 
'EXCLUSIVE'.freeze
EXPLAIN = 
'EXPLAIN '.freeze
EXPLAIN_ANALYZE = 
'EXPLAIN ANALYZE '.freeze
FOR_SHARE = 
' FOR SHARE'.freeze
INSERT_CLAUSE_METHODS = 
Dataset.clause_methods(:insert, %w'insert into columns values returning')
INSERT_CLAUSE_METHODS_91 = 
Dataset.clause_methods(:insert, %w'with insert into columns values returning')
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'select distinct columns from join where group having compounds order limit lock')
SELECT_CLAUSE_METHODS_84 = 
Dataset.clause_methods(:select, %w'with select 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'update table set from where returning')
UPDATE_CLAUSE_METHODS_91 = 
Dataset.clause_methods(:update, %w'with update table set from where returning')
SPACE = 
Dataset::SPACE
FROM = 
Dataset::FROM
APOS = 
Dataset::APOS
APOS_RE = 
Dataset::APOS_RE
DOUBLE_APOS = 
Dataset::DOUBLE_APOS
PAREN_OPEN = 
Dataset::PAREN_OPEN
PAREN_CLOSE = 
Dataset::PAREN_CLOSE
COMMA = 
Dataset::COMMA
AS = 
Dataset::AS
XOR_OP = 
' # '.freeze
CRLF = 
"\r\n".freeze
BLOB_RE = 
/[\000-\037\047\134\177-\377]/n.freeze
WINDOW = 
" WINDOW ".freeze
EMPTY_STRING = 
''.freeze

Instance Method Summary collapse

Instance Method Details

#analyze ⇒ Object

Return the results of an EXPLAIN ANALYZE query as a string



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# File 'lib/sequel/adapters/shared/postgres.rb', line 798

def analyze
  explain(:analyze=>true)
end

#complex_expression_sql_append(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 804

def complex_expression_sql_append(sql, op, args)
  case op
  when :^
    j = XOR_OP
    c = false
    args.each do |a|
      sql << j if c
      literal_append(sql, a)
      c ||= true
    end
  else
    super
  end
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 820

def explain(opts={})
  with_sql((opts[:analyze] ? EXPLAIN_ANALYZE : EXPLAIN) + select_sql).map(QUERY_PLAN).join(CRLF)
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 825

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 831

def full_text_search(cols, terms, opts = {})
  lang = opts[:language] || 'simple'
  terms = terms.join(' | ') if terms.is_a?(Array)
  filter("to_tsvector(?::regconfig, ?) @@ to_tsquery(?::regconfig, ?)", lang, full_text_string_join(cols), lang, terms)
end

#insert(*values) ⇒ Object

Insert given values into the database.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 838

def insert(*values)
  if @opts[:returning]
    # already know which columns to return, let the standard code
    # handle it
    super
  elsif @opts[:sql]
    # raw SQL used, so don't know which table is being inserted
    # into, and therefore can't determine primary key.  Run the
    # insert statement and return nil.
    super
    nil
  else
    # Force the use of RETURNING with the primary key value.
    returning(insert_pk).insert(*values){|r| return r.values.first}
  end
end

#insert_select(*values) ⇒ Object

Insert a record returning the record inserted



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# File 'lib/sequel/adapters/shared/postgres.rb', line 856

def insert_select(*values)
  returning.insert(*values){|r| return r}
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 865

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

PostgreSQL allows inserting multiple rows at once.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 875

def multi_insert_sql(columns, values)
  sql = LiteralString.new('VALUES ')
  expression_list_append(sql, values.map{|r| Array(r)})
  [insert_sql(columns, sql)]
end

#supports_cte_in_subqueries? ⇒ Boolean

PostgreSQL supports using the WITH clause in subqueries if it supports using WITH at all (i.e. on PostgreSQL 8.4+).

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 883

def supports_cte_in_subqueries?
  supports_cte?
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 888

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 893

def supports_modifying_joins?
  true
end

#supports_returning?(type) ⇒ Boolean

Returning is always supported.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 898

def supports_returning?(type)
  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 903

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 908

def supports_window_functions?
  server_version >= 80400
end

#truncate(opts = {}) ⇒ Object

Truncates the dataset. Returns nil.

Options:

:cascade

whether to use the CASCADE option, useful when truncating

tables with Foreign Keys.
:only

truncate using ONLY, so child tables are unaffected

:restart

use RESTART IDENTITY to restart any related sequences

:only and :restart only work correctly on PostgreSQL 8.4+.

Usage:

DB[:table].truncate # TRUNCATE TABLE "table"
# => nil
DB[:table].truncate(:cascade => true, :only=>true, :restart=>true) # TRUNCATE TABLE ONLY "table" RESTART IDENTITY CASCADE
# => nil



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# File 'lib/sequel/adapters/shared/postgres.rb', line 927

def truncate(opts = {})
  if opts.empty?
    super()
  else
    clone(:truncate_opts=>opts).truncate
  end
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 936

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