Class Table

tests/comparison/common.py:498–624

Represents a standard database table.

class Table(TableExpr):
  '''Represents a standard database table.'''

  def __init__(self, name):
    self.name = name
    self._cols = []  # can include CollectionColumns and StructColumns
    self._unique_cols = []
    self.alias = None
    self.is_visible = True   # Tables used in SEMI or ANTI JOINs are invisible

    # Only used for data loading. Always stored in upper-case. If set, values will be
    # something like 'PARQUET' or 'TEXT'. See cli_options.py for a full list of
    # possible values.
    self._storage_format = None

    # Only used for data loading. For Impala and Hive, this is the path to the directory
    # in the storage system, such as an HDFS URL.
    self.storage_location = None

    # Only used for data loading. Avro tables may require a separate schema definition,
    # this is the path to the schema file in the storage system, such as an HDFS URL.
    self.schema_location = None

  @property
  def identifier(self):
    return self.alias or self.name

  @property
  def primary_keys(self):
    """
    Return immutable sequence of primary keys.
    """
    return tuple(col for col in self._cols if col.is_primary_key)

  @property
  def primary_key_names(self):
    """
    Return immutable sequence for primary key names.
    """
    return tuple(col.name for col in self.primary_keys)

  @property
  def updatable_columns(self):
    """
    Return immutable sequence of columns that may be updated (i.e., not primary keys).

    If the table doesn't have primary keys, no columns are updatable.
    """
    if self.primary_keys:
      return tuple(col for col in self._cols if not col.is_primary_key)
    else:
      return ()

  @property
  def updatable_column_names(self):
    """
    Return immutable sequence of column names that may be updated
    """