class_docstr: Class implementing database connection.
  
  Example
  -------
  >>> AMPLIGRAPH_DATA_HOME='/your/path/to/datasets/'
  >>> # Initialize GraphDataLoader from .csv file
  >>> data = GraphDataLoader("data.csv", backend=SQLiteAdapter)
  >>> # Initialize GraphDataLoader from .txt file using indexer
  >>> # to map entities to integers
  >>> data = GraphDataLoader(AMPLIGRAPH_DATA_HOME + "fb15k/test.txt",
  >>>                        backend=SQLiteAdapter("database.db",
  >>>                        use_indexer=True))
  >>> for elem in data:
  >>>     print(elem)
  >>>     break
  [(1, 1, 2)]
  >>> # Populate the database with raw triples for training
  >>> with SQLiteAdapter("database.db") as backend:
  >>>     backend.populate(AMPLIGRAPH_DATA_HOME + "fb15k/train.txt",
  >>>                      dataset_type="train")
  >>> # Populate the database with indexed triples for training
  >>> with SQLiteAdapter("database.db", use_indexer=True) as backend:
  >>>     backend.populate(AMPLIGRAPH_DATA_HOME + "fb15k/train.txt",
  >>>                      dataset_type="train")
docstr: Defines SQL commands to clean the database (tables and indexes).
  
  Returns
  -------
  clean_up: list
       List of SQL commands to clean tables and indexes.
docstr_tok: ["Defines","SQL","commands","to","clean","the","database","(","tables","and","indexes",")",".","Returns","--","--","--","-","clean_up",":","list","List","of","SQL","commands","to","clean","tables","and","indexes","."]
code: def _get_clean_up(self):
      """Defines SQL commands to clean the database (tables and indexes).
  
      Returns
      -------
      clean_up: list
           List of SQL commands to clean tables and indexes.
      """
      clean_up = [
          "drop index IF EXISTS triples_table_po_idx",
          "drop index IF EXISTS triples_table_sp_idx",
          "drop index IF EXISTS triples_table_type_idx",
          "drop table IF EXISTS triples_table",
      ]
      return clean_up
  
imports: import logging
  import os
  import sqlite3
  import tempfile
  from sqlite3 import Error
  from urllib.request import pathname2url
  import numpy
  import pandas
  import tensorflow
  from ampligraph.utils.profiling import get_human_readable_size
  from .data_indexer import DataIndexer
label_desc: Use image node_id 9 for calling the SQLiteAdapter obj's underlying member method code with example usage: obj._get_clean_up() and returns: clean_up