Module: ClosureTree::ArelHelpers

Included in:
Support
Defined in:
lib/closure_tree/arel_helpers.rb

Instance Method Summary collapse

Instance Method Details

#aliased_table(table, alias_name) ⇒ Object

Helper to create an Arel node for a table with an alias



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# File 'lib/closure_tree/arel_helpers.rb', line 32

def aliased_table(table, alias_name)
  table.alias(alias_name)
end

#build_hierarchy_delete_query(hierarchy_table, id) ⇒ Object 



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# File 'lib/closure_tree/arel_helpers.rb', line 60

def build_hierarchy_delete_query(hierarchy_table, id)
  # Build the innermost subquery
  inner_subquery_manager = Arel::SelectManager.new(hierarchy_table)
  inner_subquery_manager.project(hierarchy_table[:descendant_id])
  inner_subquery_manager.where(
    hierarchy_table[:ancestor_id].eq(id)
    .or(hierarchy_table[:descendant_id].eq(id))
  )
  inner_subquery = inner_subquery_manager.as('x')

  # Build the middle subquery with DISTINCT
  middle_subquery = Arel::SelectManager.new
  middle_subquery.from(inner_subquery)
  middle_subquery.project(inner_subquery[:descendant_id]).distinct

  # Build the DELETE statement
  delete_manager = Arel::DeleteManager.new
  delete_manager.from(hierarchy_table)
  delete_manager.where(hierarchy_table[:descendant_id].in(middle_subquery))

  delete_manager
end

#build_hierarchy_insert_query(hierarchy_table, node_id, parent_id) ⇒ Object

Build Arel queries for hierarchy operations



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# File 'lib/closure_tree/arel_helpers.rb', line 37

def build_hierarchy_insert_query(hierarchy_table, node_id, parent_id)
  x = aliased_table(hierarchy_table, 'x')

  # Build the SELECT subquery - use SelectManager
  select_query = Arel::SelectManager.new(x)
  select_query.project(
    x[:ancestor_id],
    Arel.sql(quote(node_id)),
    x[:generations] + 1
  )
  select_query.where(x[:descendant_id].eq(parent_id))

  # Build the INSERT statement
  insert_manager = Arel::InsertManager.new
  insert_manager.into(hierarchy_table)
  insert_manager.columns << hierarchy_table[:ancestor_id]
  insert_manager.columns << hierarchy_table[:descendant_id]
  insert_manager.columns << hierarchy_table[:generations]
  insert_manager.select(select_query)

  insert_manager
end

#hierarchy_table ⇒ Object

Get hierarchy table using the model_class This is for Support class methods



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# File 'lib/closure_tree/arel_helpers.rb', line 24

def hierarchy_table
  @hierarchy_table ||= begin
    hierarchy_class_name = options[:hierarchy_class_name] || "#{model_class}Hierarchy"
    hierarchy_class_name.constantize.arel_table
  end
end

#hierarchy_table_for(model) ⇒ Object

Get hierarchy table from a model class This method should be called from instance methods where hierarchy_class is available



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# File 'lib/closure_tree/arel_helpers.rb', line 12

def hierarchy_table_for(model)
  if model.respond_to?(:hierarchy_class)
    model.hierarchy_class.arel_table
  elsif model.class.respond_to?(:hierarchy_class)
    model.class.hierarchy_class.arel_table
  else
    raise ArgumentError, "Cannot find hierarchy_class for #{model}"
  end
end

#model_table ⇒ Object

Get model’s arel table



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# File 'lib/closure_tree/arel_helpers.rb', line 6

def model_table
  @model_table ||= model_class.arel_table
end

#to_sql_with_connection(arel_manager) ⇒ Object

Convert an Arel AST to SQL using the correct connection’s visitor This ensures proper quoting for the specific database adapter (MySQL uses backticks, PostgreSQL uses double quotes)



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# File 'lib/closure_tree/arel_helpers.rb', line 85

def to_sql_with_connection(arel_manager)
  collector = Arel::Collectors::SQLString.new
  visitor = connection.visitor
  visitor.accept(arel_manager.ast, collector).value
end