sqlalchemy_mptt package

Events

Base events

SQLAlchemy events extension

sqlalchemy_mptt.events.mptt_before_insert(mapper, connection, instance)[source]

Based on example https://bitbucket.org/zzzeek/sqlalchemy/src/73095b353124/examples/nested_sets/nested_sets.py?at=master

sqlalchemy_mptt.events.mptt_before_delete(mapper, connection, instance, delete=True)[source]
sqlalchemy_mptt.events.mptt_before_update(mapper, connection, instance)[source]

Based on this example: http://stackoverflow.com/questions/889527/move-node-in-nested-set

class sqlalchemy_mptt.events.TreesManager(base_class)[source]

Manages events dispatching for all subclasses of a given class.

Hidden method

sqlalchemy_mptt.events._insert_subtree(table, connection, node_size, node_pos_left, node_pos_right, parent_pos_left, parent_pos_right, subtree, parent_tree_id, parent_level, node_level, left_sibling, table_pk)[source]

Mixins

SQLAlchemy nested sets mixin

class sqlalchemy_mptt.mixins.BaseNestedSets[source]

Base mixin for MPTT model.

Example:

from sqlalchemy import Boolean, Column, create_engine, Integer
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker

from sqlalchemy_mptt.mixins import BaseNestedSets

Base = declarative_base()


class Tree(Base, BaseNestedSets):
    __tablename__ = "tree"

    id = Column(Integer, primary_key=True)
    visible = Column(Boolean)

    def __repr__(self):
        return "<Node (%s)>" % self.id
tree_id()

Represents a column in a database table.

parent_id
parent
left()

Represents a column in a database table.

right()

Represents a column in a database table.

level()

Represents a column in a database table.

drilldown_tree(session=None, json=False, json_fields=None)[source]

This method generate a branch from a tree, begining with current node.

For example:

node7.drilldown_tree()

level           Nested sets example
1                    1(1)22       ---------------------
        _______________|_________|_________            |
       |               |         |         |           |
2    2(2)5           6(4)11      |      12(7)21        |
       |               ^         |         ^           |
3    3(3)4       7(5)8   9(6)10  | 13(8)16   17(10)20  |
                                 |    |          |     |
4                                | 14(9)15   18(11)19  |
                                 |                     |
                                  ---------------------

Example in tests:

  • sqlalchemy_mptt.tests.cases.get_tree.test_drilldown_tree
classmethod get_default_level()[source]

Compatibility with Django MPTT: level value for root node. See https://github.com/uralbash/sqlalchemy_mptt/issues/56

classmethod get_tree(session=None, json=False, json_fields=None, query=None)[source]

This method generate tree of current node table in dict or json format. You can make custom query with attribute query. By default it return all nodes in table.

Args:
session (sqlalchemy.orm.session.Session): SQLAlchemy session
Kwargs:

json (bool): if True return JSON jqTree format json_fields (function): append custom fields in JSON query (function): it takes sqlalchemy.orm.query.Query object as an argument, and returns in a modified form

def query(nodes):
    return nodes.filter(node.__class__.tree_id.is_(node.tree_id))

node.get_tree(session=DBSession, json=True, query=query)

Example:

  • sqlalchemy_mptt.tests.cases.get_tree.test_get_tree
  • sqlalchemy_mptt.tests.cases.get_tree.test_get_json_tree
  • sqlalchemy_mptt.tests.cases.get_tree.test_get_json_tree_with_custom_field
is_ancestor_of(other, inclusive=False)[source]

class or instance level method which returns True if self is ancestor (closer to root) of other else False. Optional flag inclusive on whether or not to treat self as ancestor of self.

For example see:

  • sqlalchemy_mptt.tests.cases.integrity.test_hierarchy_structure
is_descendant_of(other, inclusive=False)[source]

class or instance level method which returns True if self is descendant (farther from root) of other else False. Optional flag inclusive on whether or not to treat self as descendant of self.

For example see:

  • sqlalchemy_mptt.tests.cases.integrity.test_hierarchy_structure
leftsibling_in_level()[source]

Node to the left of the current node at the same level

For example see sqlalchemy_mptt.tests.cases.get_tree.test_leftsibling_in_level

move_after(node_id)[source]

Moving one node of tree after another

For example see sqlalchemy_mptt.tests.cases.move_node.test_move_after_function

move_before(node_id)[source]

Moving one node of tree before another

For example see:

  • sqlalchemy_mptt.tests.cases.move_node.test_move_before_function
  • sqlalchemy_mptt.tests.cases.move_node.test_move_before_to_other_tree
  • sqlalchemy_mptt.tests.cases.move_node.test_move_before_to_top_level
move_inside(parent_id)[source]

Moving one node of tree inside another

For example see:

  • sqlalchemy_mptt.tests.cases.move_node.test_move_inside_function
  • sqlalchemy_mptt.tests.cases.move_node.test_move_inside_to_the_same_parent_function
path_to_root(session=None)[source]

Generate path from a leaf or intermediate node to the root.

For example:

node11.path_to_root()

level           Nested sets example

                 -----------------------------------------
1               |    1(1)22                               |
        ________|______|_____________________             |
       |        |      |                     |            |
       |         ------+---------            |            |
2    2(2)5           6(4)11      | --     12(7)21         |
       |               ^             |   /      \         |
3    3(3)4       7(5)8   9(6)10      ---/----    \        |
                                    13(8)16 |  17(10)20   |
                                       |    |     |       |
4                                   14(9)15 | 18(11)19    |
                                            |             |
                                             -------------
classmethod rebuild(session, tree_id=None)[source]

This function rebuid tree.

Args:
session (sqlalchemy.orm.session.Session): SQLAlchemy session
Kwargs:
tree_id (int or str): id of tree, default None

Example:

  • sqlalchemy_mptt.tests.TestTree.test_rebuild
classmethod rebuild_tree(session, tree_id)[source]

This method rebuid tree.

Args:
session (sqlalchemy.orm.session.Session): SQLAlchemy session tree_id (int or str): id of tree

Example:

  • sqlalchemy_mptt.tests.cases.get_tree.test_rebuild

Tests

Base tests

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