Class: WorkerPlugins::SelectColumnWithTypeCast

Inherits:
ApplicationService
  • Object
show all
Defined in:
app/services/worker_plugins/select_column_with_type_cast.rb

Instance Method Summary collapse

Methods inherited from ApplicationService

#db_now_value, #mysql?, #postgres?, #quote, #quote_column, #quote_table, #relation_unscoped?, #sqlite?

Instance Method Details

#column_to_select ⇒ Object 



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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 16

def column_to_select
  @column_to_select ||= model_class.column_for_attribute(column_name_to_select)
end

#model_class ⇒ Object 



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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 20

def model_class
  @model_class ||= query.klass
end

#mysql_implicit_conversion_safe? ⇒ Boolean

On MySQL / MariaDB, implicit conversion handles comparisons between any string-ish column types (VARCHAR, CHAR, BINARY, UUID, or types AR doesn’t recognize — e.g. MariaDB’s native UUID type when using an older mysql2 adapter). The explicit CAST is only needed when one side is numeric, because MySQL would then force a string → number conversion that loses rows containing non-numeric values.

Returns:

  • (Boolean) 


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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 60

def mysql_implicit_conversion_safe?
  return false unless mysql?

  !numeric_type?(column_to_select.type) && !numeric_type?(column_to_compare_with.type)
end

#numeric_type?(type) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 66

def numeric_type?(type)
  %i[integer decimal float bigint].include?(type)
end

#perform ⇒ Object 



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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 4

def perform
  return succeed! query.select(column_name_to_select) if same_type?

  if column_to_compare_with.type == :integer
    succeed! query_with_integer
  elsif column_to_compare_with.type == :uuid
    succeed! query_with_uuid
  else
    succeed! query_with_varchar
  end
end

#query_with_integer ⇒ Object 



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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 24

def query_with_integer
  if mysql?
    query.select("CAST(#{model_class.table_name}.#{column_name_to_select} AS SIGNED)")
  else
    query.select("CAST(#{model_class.table_name}.#{column_name_to_select} AS BIGINT)")
  end
end

#query_with_uuid ⇒ Object 



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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 40

def query_with_uuid
  if postgres?
    query.select("CAST(#{model_class.table_name}.#{column_name_to_select} AS UUID)")
  else
    query_with_varchar
  end
end

#query_with_varchar ⇒ Object 



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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 32

def query_with_varchar
  if mysql?
    query.select("CAST(#{model_class.table_name}.#{column_name_to_select} AS CHAR)")
  else
    query.select("CAST(#{model_class.table_name}.#{column_name_to_select} AS VARCHAR)")
  end
end

#same_type? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/services/worker_plugins/select_column_with_type_cast.rb', line 48

def same_type?
  return true if column_to_select.type == column_to_compare_with.type

  mysql_implicit_conversion_safe?
end