Module: Sequel::Plugins::PagedOperations::DatasetMethods

Defined in:
lib/sequel/plugins/paged_operations.rb

Instance Method Summary collapse

Instance Method Details

#paged_datasets(opts = OPTS) {|ds| ... } ⇒ Object

Yield datasets for subsets of the receiver that are limited to no more than 1000 rows (you can configure the number of rows using :rows_per_page).

Options:

:rows_per_page

The maximum number of rows in each yielded dataset (unless concurrent modifications are made to the table).

Yields:

  • (ds) 


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# File 'lib/sequel/plugins/paged_operations.rb', line 91

def paged_datasets(opts=OPTS)
  unless defined?(yield)
    return enum_for(:paged_datasets, opts)
  end

  pk = _paged_operations_pk(:paged_update)
  base_offset_ds = offset_ds = _paged_operations_offset_ds(opts)
  first = nil

  while last = offset_ds.get(pk)
    ds = where(pk < last)
    ds = ds.where(pk >= first) if first
    yield ds
    first = last
    offset_ds = base_offset_ds.where(pk >= first)
  end

  ds = self
  ds = ds.where(pk >= first) if first
  yield ds
  nil
end

#paged_delete(opts = OPTS) ⇒ Object

Delete all rows of the dataset using using multiple queries so that no more than 1000 rows are deleted at a time (you can configure the number of rows using :rows_per_page).

Options:

:rows_per_page

The maximum number of rows affected by each DELETE query (unless concurrent modifications are made to the table).



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# File 'lib/sequel/plugins/paged_operations.rb', line 121

def paged_delete(opts=OPTS)
  if (db.database_type == :oracle && !supports_fetch_next_rows?) || (db.database_type == :mssql && !is_2012_or_later?)
    raise Error, "paged_delete is not supported on MSSQL/Oracle when using emulated offsets"
  end
  pk = _paged_operations_pk(:paged_delete)
  rows_deleted = 0
  offset_ds = _paged_operations_offset_ds(opts)
  while last = offset_ds.get(pk)
    rows_deleted += where(pk < last).delete
  end
  rows_deleted + delete
end

#paged_update(values, opts = OPTS) ⇒ Object

Update all rows of the dataset using using multiple queries so that no more than 1000 rows are updated at a time (you can configure the number of rows using :rows_per_page). All arguments are passed to Dataset#update.

Options:

:rows_per_page

The maximum number of rows affected by each UPDATE query (unless concurrent modifications are made to the table).



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# File 'lib/sequel/plugins/paged_operations.rb', line 142

def paged_update(values, opts=OPTS)
  rows_updated = 0
  paged_datasets(opts) do |ds|
    rows_updated += ds.update(values)
  end
  rows_updated
end