Class: NoSE::Update

Inherits:
Statement show all
Includes:
StatementConditions, StatementSettings, StatementSupportQuery
Defined in:
lib/nose/statements/update.rb

Overview

A representation of an update in the workload

Instance Attribute Summary

Attributes included from StatementSettings

#settings

Attributes included from StatementConditions

#conditions

Attributes inherited from Statement

#comment, #entity, #eq_fields, #graph, #group, #key_path, #label, #range_field, #text

Class Method Summary collapse

Instance Method Summary collapse

Methods included from StatementSupportQuery

#modifies_index?

Methods included from StatementSettings

included

Methods included from StatementConditions

included, #populate_conditions

Methods inherited from Statement

#materialize_view, #read_only?, #to_color

Constructor Details

#initialize(params, text, group: nil, label: nil) ⇒ Update

Returns a new instance of Update.



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# File 'lib/nose/statements/update.rb', line 10

def initialize(params, text, group: nil, label: nil)
  super params, text, group: group, label: label

  populate_conditions params
  @settings = params[:settings]
end

Class Method Details

.parse(tree, params, text, group: nil, label: nil) ⇒ Update

Build a new update from a provided parse tree

Returns:



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# File 'lib/nose/statements/update.rb', line 19

def self.parse(tree, params, text, group: nil, label: nil)
  conditions_from_tree tree, params
  settings_from_tree tree, params

  Update.new params, text, group: group, label: label
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql? 



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# File 'lib/nose/statements/update.rb', line 37

def ==(other)
  other.is_a?(Update) &&
    @graph == other.graph &&
    entity == other.entity &&
    @settings == other.settings &&
    @conditions == other.conditions
end

#given_fields ⇒ Object

The condition fields are provided with the update Note that we don’t include the settings here because we care about the previously existing values in the database



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# File 'lib/nose/statements/update.rb', line 97

def given_fields
  @conditions.each_value.map(&:field)
end

#hash ⇒ Object 



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# File 'lib/nose/statements/update.rb', line 46

def hash
  @hash ||= [@graph, entity, @settings, @conditions].hash
end

#requires_delete?(index) ⇒ Boolean

Specifies that updates require deletion

Returns:

  • (Boolean) 


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# File 'lib/nose/statements/update.rb', line 56

def requires_delete?(index)
  !(settings.map(&:field).to_set &
    (index.hash_fields + index.order_fields.to_set)).empty?
end

#requires_insert?(_index) ⇒ Boolean

Specifies that updates require insertion

Returns:

  • (Boolean) 


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# File 'lib/nose/statements/update.rb', line 51

def requires_insert?(_index)
  true
end

#support_queries(index) ⇒ Array<SupportQuery>

Get the support queries for updating an index

Returns:



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# File 'lib/nose/statements/update.rb', line 63

def support_queries(index)
  return [] unless modifies_index? index

  # Get the updated fields and check if an update is necessary
  set_fields = settings.map(&:field).to_set

  # We only need to fetch all the fields if we're updating a key
  updated_key = !(set_fields &
                  (index.hash_fields + index.order_fields)).empty?

  select = if updated_key
             index.all_fields
           else
             index.hash_fields + index.order_fields
           end - set_fields - @conditions.each_value.map(&:field)
  return [] if select.empty?

  support_queries = []

  graph = @graph.dup
  support_fields = select.select do |field|
    field.parent == entity
  end.to_set
  support_fields << entity.id_field \
    unless @conditions.each_value.map(&:field).include? entity.id_field

  support_queries << build_support_query(entity, index, graph,
                                         support_fields, conditions)
  support_queries.compact + support_queries_for_entity(index, select)
end

#unparse ⇒ String

Produce the SQL text corresponding to this update

Returns:

  • (String) 


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# File 'lib/nose/statements/update.rb', line 28

def unparse
  update = "UPDATE #{entity.name} "
  update += "FROM #{from_path @key_path} "
  update << settings_clause
  update << where_clause

  update
end