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Class: Arel::Visitors::PostgreSQL

Do not use. This class is for internal use only.
Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, ToSql, Visitor
Instance Chain:
self, ToSql, Visitor
Inherits: Arel::Visitors::ToSql
Defined in: activerecord/lib/arel/visitors/postgresql.rb

Constant Summary

ToSql - Inherited

BIND_BLOCK

Class Method Summary

ToSql - Inherited

.new

Visitor - Inherited

.new, .dispatch_cache

Instance Attribute Summary

Visitor - Inherited

#dispatch

Instance Method Summary

ToSql - Inherited

#compile, #aggregate, #bind_block,
#build_subselect

FIXME: we should probably have a 2-pass visitor for this.
#collect_ctes, #collect_nodes_for, #collect_optimizer_hints,
#grouping_parentheses

Used by some visitors to enclose select queries in parentheses.
#has_group_by_and_having?, #has_join_sources?, #has_limit_or_offset_or_orders?, #infix_value, #infix_value_with_paren, #inject_join, #is_distinct_from, #maybe_visit,
#prepare_delete_statement

Alias for ToSql#prepare_update_statement.
#prepare_update_statement

The default strategy for an UPDATE with joins is to use a subquery.
#quote, #quote_column_name, #quote_table_name, #require_parentheses?, #sanitize_as_sql_comment, #unboundable?, #unsupported, #visit_ActiveModel_Attribute,
#visit_ActiveSupport_Multibyte_Chars

Alias for ToSql#unsupported.
#visit_ActiveSupport_StringInquirer

Alias for ToSql#unsupported.
#visit_Arel_Attributes_Attribute, #visit_Arel_Nodes_And, #visit_Arel_Nodes_As, #visit_Arel_Nodes_Ascending, #visit_Arel_Nodes_Assignment, #visit_Arel_Nodes_Avg, #visit_Arel_Nodes_Between, #visit_Arel_Nodes_Bin, #visit_Arel_Nodes_BindParam, #visit_Arel_Nodes_BoundSqlLiteral, #visit_Arel_Nodes_Case, #visit_Arel_Nodes_Casted, #visit_Arel_Nodes_Comment, #visit_Arel_Nodes_Count, #visit_Arel_Nodes_Cte, #visit_Arel_Nodes_CurrentRow, #visit_Arel_Nodes_DeleteStatement, #visit_Arel_Nodes_Descending, #visit_Arel_Nodes_Distinct, #visit_Arel_Nodes_DistinctOn, #visit_Arel_Nodes_DoesNotMatch, #visit_Arel_Nodes_Else, #visit_Arel_Nodes_Equality, #visit_Arel_Nodes_Except, #visit_Arel_Nodes_Exists, #visit_Arel_Nodes_Extract, #visit_Arel_Nodes_False, #visit_Arel_Nodes_Filter, #visit_Arel_Nodes_Following, #visit_Arel_Nodes_Fragments, #visit_Arel_Nodes_FullOuterJoin, #visit_Arel_Nodes_GreaterThan, #visit_Arel_Nodes_GreaterThanOrEqual, #visit_Arel_Nodes_Group, #visit_Arel_Nodes_Grouping, #visit_Arel_Nodes_HomogeneousIn, #visit_Arel_Nodes_In, #visit_Arel_Nodes_InfixOperation, #visit_Arel_Nodes_InnerJoin, #visit_Arel_Nodes_InsertStatement, #visit_Arel_Nodes_Intersect, #visit_Arel_Nodes_IsDistinctFrom, #visit_Arel_Nodes_IsNotDistinctFrom, #visit_Arel_Nodes_JoinSource, #visit_Arel_Nodes_LessThan, #visit_Arel_Nodes_LessThanOrEqual, #visit_Arel_Nodes_Limit, #visit_Arel_Nodes_Lock, #visit_Arel_Nodes_Matches, #visit_Arel_Nodes_Max, #visit_Arel_Nodes_Min, #visit_Arel_Nodes_NamedFunction, #visit_Arel_Nodes_NamedWindow, #visit_Arel_Nodes_Not, #visit_Arel_Nodes_NotEqual, #visit_Arel_Nodes_NotIn, #visit_Arel_Nodes_NotRegexp,
#visit_Arel_Nodes_NullsFirst

NullsFirst is available on all but MySQL, where it is redefined.
#visit_Arel_Nodes_NullsLast, #visit_Arel_Nodes_Offset, #visit_Arel_Nodes_On, #visit_Arel_Nodes_OptimizerHints, #visit_Arel_Nodes_Or, #visit_Arel_Nodes_OuterJoin, #visit_Arel_Nodes_Over, #visit_Arel_Nodes_Preceding,
#visit_Arel_Nodes_Quoted

Alias for ToSql#visit_Arel_Nodes_Casted.
#visit_Arel_Nodes_Range, #visit_Arel_Nodes_Regexp, #visit_Arel_Nodes_RightOuterJoin, #visit_Arel_Nodes_Rows, #visit_Arel_Nodes_SelectCore,
#visit_Arel_Nodes_SelectOptions

The Oracle enhanced adapter uses this private method, see github.com/rsim/oracle-enhanced/issues/2186.
#visit_Arel_Nodes_SelectStatement, #visit_Arel_Nodes_SqlLiteral, #visit_Arel_Nodes_StringJoin, #visit_Arel_Nodes_Sum, #visit_Arel_Nodes_TableAlias, #visit_Arel_Nodes_True, #visit_Arel_Nodes_UnaryOperation, #visit_Arel_Nodes_Union, #visit_Arel_Nodes_UnionAll, #visit_Arel_Nodes_UnqualifiedColumn, #visit_Arel_Nodes_UpdateStatement, #visit_Arel_Nodes_ValuesList, #visit_Arel_Nodes_When, #visit_Arel_Nodes_Window, #visit_Arel_Nodes_With, #visit_Arel_Nodes_WithRecursive, #visit_Arel_SelectManager, #visit_Arel_Table, #visit_Array,
#visit_BigDecimal

Alias for ToSql#unsupported.
#visit_Class

Alias for ToSql#unsupported.
#visit_Date

Alias for ToSql#unsupported.
#visit_DateTime

Alias for ToSql#unsupported.
#visit_FalseClass

Alias for ToSql#unsupported.
#visit_Float

Alias for ToSql#unsupported.
#visit_Hash

Alias for ToSql#unsupported.
#visit_Integer,
#visit_NilClass

Alias for ToSql#unsupported.
#visit_Set

Alias for ToSql#visit_Array.
#visit_String

Alias for ToSql#unsupported.
#visit_Symbol

Alias for ToSql#unsupported.
#visit_Time

Alias for ToSql#unsupported.
#visit_TrueClass

Alias for ToSql#unsupported.

Visitor - Inherited

#accept, #get_dispatch_cache, #visit

Constructor Details

This class inherits a constructor from Arel::Visitors::ToSql

Instance Method Details

#bind_block (private)

[ GitHub ] 

  


# File 'activerecord/lib/arel/visitors/postgresql.rb', line 151



def bind_block; BIND_BLOCK; end


  








  

    #grouping_array_or_grouping_element(o, collector)   (private)
  



  

    

Utilized by GroupingSet, Cube & RollUp visitors to handle grouping aggregation semantics


  



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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 155



def grouping_array_or_grouping_element(o, collector)
  if o.expr.is_a? Array
    collector << "( "
    visit o.expr, collector
    collector << " )"
  else
    visit o.expr, collector
  end
end


  








  

    #prepare_update_statement(o)   (private)
  



  

    

In the simple case, PostgreSQL allows us to place FROM or JOINs directly into the UPDATE query. However, this does not allow for LIMIT, OFFSET and ORDER. To support these, we must use a subquery.


  



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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 62



def prepare_update_statement(o)
  if has_join_sources?(o) && !has_limit_or_offset_or_orders?(o) && !has_group_by_and_having?(o) &&
    # The PostgreSQL dialect isn't flexible enough to allow anything other than a inner join
    # for the first join:
    #   UPDATE table SET .. FROM joined_table WHERE ...
    (o.relation.right.all? { |join| join.is_a?(Arel::Nodes::InnerJoin) || join.right.expr.right.relation != o.relation.left })
    o
  else
    super
  end
end


  








  

    #visit_Arel_Nodes_Cube(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 116



def visit_Arel_Nodes_Cube(o, collector)
  collector << "CUBE"
  grouping_array_or_grouping_element o, collector
end


  








  

    #visit_Arel_Nodes_DistinctOn(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 106



def visit_Arel_Nodes_DistinctOn(o, collector)
  collector << "DISTINCT ON ( "
  visit(o.expr, collector) << " )"
end


  








  

    #visit_Arel_Nodes_DoesNotMatch(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 85



def visit_Arel_Nodes_DoesNotMatch(o, collector)
  op = o.case_sensitive ? " NOT LIKE " : " NOT ILIKE "
  collector = infix_value o, collector, op
  if o.escape
    collector << " ESCAPE "
    visit o.escape, collector
  else
    collector
  end
end


  








  

    #visit_Arel_Nodes_GroupingElement(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 111



def visit_Arel_Nodes_GroupingElement(o, collector)
  collector << "( "
  visit(o.expr, collector) << " )"
end


  








  

    #visit_Arel_Nodes_GroupingSet(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 126



def visit_Arel_Nodes_GroupingSet(o, collector)
  collector << "GROUPING SETS"
  grouping_array_or_grouping_element o, collector
end


  








  

    #visit_Arel_Nodes_IsDistinctFrom(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 142



def visit_Arel_Nodes_IsDistinctFrom(o, collector)
  collector = visit o.left, collector
  collector << " IS DISTINCT FROM "
  visit o.right, collector
end


  








  

    #visit_Arel_Nodes_IsNotDistinctFrom(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 136



def visit_Arel_Nodes_IsNotDistinctFrom(o, collector)
  collector = visit o.left, collector
  collector << " IS NOT DISTINCT FROM "
  visit o.right, collector
end


  








  

    #visit_Arel_Nodes_Lateral(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 131



def visit_Arel_Nodes_Lateral(o, collector)
  collector << "LATERAL "
  grouping_parentheses o.expr, collector
end


  








  

    #visit_Arel_Nodes_Matches(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 74



def visit_Arel_Nodes_Matches(o, collector)
  op = o.case_sensitive ? " LIKE " : " ILIKE "
  collector = infix_value o, collector, op
  if o.escape
    collector << " ESCAPE "
    visit o.escape, collector
  else
    collector
  end
end


  








  

    #visit_Arel_Nodes_NotRegexp(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 101



def visit_Arel_Nodes_NotRegexp(o, collector)
  op = o.case_sensitive ? " !~ " : " !~* "
  infix_value o, collector, op
end


  








  

    #visit_Arel_Nodes_Regexp(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 96



def visit_Arel_Nodes_Regexp(o, collector)
  op = o.case_sensitive ? " ~ " : " ~* "
  infix_value o, collector, op
end


  








  

    #visit_Arel_Nodes_RollUp(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 121



def visit_Arel_Nodes_RollUp(o, collector)
  collector << "ROLLUP"
  grouping_array_or_grouping_element o, collector
end


  








  

    #visit_Arel_Nodes_UpdateStatement(o, collector)   (private)
  

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# File 'activerecord/lib/arel/visitors/postgresql.rb', line 7



def visit_Arel_Nodes_UpdateStatement(o, collector)
  collector.retryable = false
  o = prepare_update_statement(o)

  collector << "UPDATE "

  # UPDATE with JOIN is in the form of:
  #
  #   UPDATE t1
  #   SET ..
  #   FROM t2
  #   WHERE t1.join_id = t2.join_id
  #
  # Or if more than one join is present:
  #
  #   UPDATE t1
  #   SET ..
  #   FROM t2
  #   JOIN t3 ON t2.join_id = t3.join_id
  #   WHERE t1.join_id = t2.join_id
  if has_join_sources?(o)
    visit o.relation.left, collector
    collect_nodes_for o.values, collector, " SET "
    collector << " FROM "
    first_join, *remaining_joins = o.relation.right
    from_items = remaining_joins.extract! do |join|
      join.right.expr.right.relation == o.relation.left
    end

    from_where = [first_join.left] + from_items.map(&:left)
    collect_nodes_for from_where, collector, " ", ", "

    if remaining_joins && !remaining_joins.empty?
      collector << " "
      remaining_joins.each do |join|
        visit join, collector
        collector << " "
      end
    end

    from_where = [first_join.right.expr] + from_items.map { |i| i.right.expr }
    collect_nodes_for from_where + o.wheres, collector, " WHERE ", " AND "
  else
    collector = visit o.relation, collector
    collect_nodes_for o.values, collector, " SET "
    collect_nodes_for o.wheres, collector, " WHERE ", " AND "
  end

  collect_nodes_for o.orders, collector, " ORDER BY "
  maybe_visit o.limit, collector
end