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')
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
ESCAPE = 
Dataset::ESCAPE
BACKSLASH = 
Dataset::BACKSLASH
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
LOCK_MODES = 
['ACCESS SHARE', 'ROW SHARE', 'ROW EXCLUSIVE', 'SHARE UPDATE EXCLUSIVE', 'SHARE', 'SHARE ROW EXCLUSIVE', 'EXCLUSIVE', 'ACCESS EXCLUSIVE'].each{|s| s.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 1156

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 (#), and use the ILIKE and NOT ILIKE operators.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 1163

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
  when :ILIKE, :'NOT ILIKE'
    sql << PAREN_OPEN
    literal_append(sql, args.at(0))
    sql << SPACE << op.to_s << SPACE
    literal_append(sql, args.at(1))
    sql << ESCAPE
    literal_append(sql, BACKSLASH)
    sql << PAREN_CLOSE
  else
    super
  end
end

#disable_insert_returning ⇒ Object

Disables automatic use of INSERT … RETURNING. You can still use returning manually to force the use of RETURNING when inserting.

This is designed for cases where INSERT RETURNING cannot be used, such as when you are using partitioning with trigger functions or conditional rules, or when you are using a PostgreSQL version less than 8.2, or a PostgreSQL derivative that does not support returning.

Note that when this method is used, insert will not return the primary key of the inserted row, you will have to get the primary key of the inserted row before inserting via nextval, or after inserting via currval or lastval (making sure to use the same database connection for currval or lastval).



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# File 'lib/sequel/adapters/shared/postgres.rb', line 1200

def disable_insert_returning
  clone(:disable_insert_returning=>true)
end

#explain(opts = OPTS) ⇒ Object

Return the results of an EXPLAIN query as a string



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# File 'lib/sequel/adapters/shared/postgres.rb', line 1205

def explain(opts=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 1210

def for_share
  lock_style(:share)
end

#full_text_search(cols, terms, opts = OPTS) ⇒ Object

Run a full text search on PostgreSQL. By default, searching for the inclusion of any of the terms in any of the cols.

Options:

:language

The language to use for the search (default: ‘simple’)

:plain

Whether a plain search should be used (default: false). In this case, terms should be a single string, and it will do a search where cols contains all of the words in terms. This ignores search operators in terms.

:phrase

Similar to :plain, but also adding an ILIKE filter to ensure that returned rows also include the exact phrase used.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 1224

def full_text_search(cols, terms, opts = OPTS)
  lang = opts[:language] || 'simple'
  terms = terms.join(' | ') if terms.is_a?(Array)
  to_tsquery = (opts[:phrase] || opts[:plain]) ? 'plainto_tsquery' : 'to_tsquery'

  ds = where(Sequel.lit(["(to_tsvector(", "::regconfig, ", ") @@ #{to_tsquery}(", "::regconfig, ", "))"], lang, full_text_string_join(cols), lang, terms))

  if opts[:phrase]
    ds = ds.grep(cols, "%#{escape_like(terms)}%", :case_insensitive=>true)
  end

  ds
end

#insert(*values) ⇒ Object

Insert given values into the database.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 1239

def insert(*values)
  if @opts[:returning]
    # Already know which columns to return, let the standard code handle it
    super
  elsif @opts[:sql] || @opts[:disable_insert_returning]
    # Raw SQL used or RETURNING disabled, just use the default behavior
    # and return nil since sequence is not known.
    super
    nil
  else
    # Force the use of RETURNING with the primary key value,
    # unless it has been disabled.
    returning(insert_pk).insert(*values){|r| return r.values.first}
  end
end

#insert_select(*values) ⇒ Object

Insert a record returning the record inserted. Always returns nil without inserting a query if disable_insert_returning is used.



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# File 'lib/sequel/adapters/shared/postgres.rb', line 1257

def insert_select(*values)
  returning.insert(*values){|r| return r} unless @opts[:disable_insert_returning]
end

#lock(mode, opts = 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 1266

def lock(mode, opts=OPTS)
  if block_given? # perform locking inside a transaction and yield to block
    @db.transaction(opts){lock(mode, opts); yield}
  else
    sql = 'LOCK TABLE '
    source_list_append(sql, @opts[:from])
    mode = mode.to_s.upcase.strip
    unless LOCK_MODES.include?(mode)
      raise Error, "Unsupported lock mode: #{mode}"
    end
    sql << " IN #{mode} MODE"
    @db.execute(sql, opts)
  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 1283

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 1291

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 1296

def supports_distinct_on?
  true
end

#supports_insert_select? ⇒ Boolean

True unless insert returning has been disabled for this dataset.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1301

def supports_insert_select?
  !@opts[:disable_insert_returning]
end

#supports_lateral_subqueries? ⇒ Boolean

PostgreSQL 9.3rc1+ supports lateral subqueries

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1306

def supports_lateral_subqueries?
  server_version >= 90300
end

#supports_modifying_joins? ⇒ Boolean

PostgreSQL supports modifying joined datasets

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1311

def supports_modifying_joins?
  true
end

#supports_regexp? ⇒ Boolean

PostgreSQL supports pattern matching via regular expressions

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1321

def supports_regexp?
  true
end

#supports_returning?(type) ⇒ Boolean

Returning is always supported.

Returns:

  • (Boolean) 


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1316

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 1326

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 1331

def supports_window_functions?
  server_version >= 80400
end

#truncate(opts = 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 1350

def truncate(opts = 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 1359

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