Examples illustrating the usage of the “association object” pattern, │ │ │ │ where an intermediary class mediates the relationship between two │ │ │ │ classes that are associated in a many-to-many pattern.
│ │ │ │Listing of files:
proxied_association.py - Same example as basic_association, adding in
│ │ │ │ +usage of sqlalchemy.ext.associationproxy to make explicit references
│ │ │ │ +to OrderItem optional.
dict_of_sets_with_default.py - An advanced association proxy example which │ │ │ │ illustrates nesting of association proxies to produce multi-level Python │ │ │ │ collections, in this case a dictionary with string keys and sets of integers │ │ │ │ as values, which conceal the underlying mapped classes.
│ │ │ │basic_association.py - Illustrate a many-to-many relationship between an │ │ │ │ “Order” and a collection of “Item” objects, associating a purchase price │ │ │ │ with each via an association object called “OrderItem”
│ │ │ │proxied_association.py - Same example as basic_association, adding in
│ │ │ │ -usage of sqlalchemy.ext.associationproxy to make explicit references
│ │ │ │ -to OrderItem optional.
Examples illustrating the asyncio engine feature of SQLAlchemy.
│ │ │ │Listing of files:
basic.py - Illustrates the asyncio engine / connection interface.
│ │ │ │greenlet_orm.py - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession object │ │ │ │ -for asynchronous ORM use, including the optional run_sync() method.
│ │ │ │ +async_orm.py - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession object │ │ │ │ +for asynchronous ORM use.
│ │ │ │gather_orm_statements.py - Illustrates how to run many statements concurrently using asyncio.gather()
│ │ │ │ along many asyncio database connections, merging ORM results into a single
│ │ │ │ AsyncSession.
async_orm.py - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession object │ │ │ │ -for asynchronous ORM use.
│ │ │ │ +greenlet_orm.py - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession object │ │ │ │ +for asynchronous ORM use, including the optional run_sync() method.
│ │ │ │An example of persistence for a directed graph structure. The
│ │ │ │ @@ -384,14 +384,18 @@
│ │ │ │ subclassing the HasAddresses mixin, which ensures that the
│ │ │ │ parent class is provided with an addresses collection
│ │ │ │ which contains Address objects.
The discriminator_on_association.py and generic_fk.py scripts │ │ │ │ are modernized versions of recipes presented in the 2007 blog post │ │ │ │ Polymorphic Associations with SQLAlchemy.
│ │ │ │Listing of files:
table_per_related.py - Illustrates a generic association which persists association │ │ │ │ +objects within individual tables, each one generated to persist │ │ │ │ +those objects on behalf of a particular parent class.
│ │ │ │ +discriminator_on_association.py - Illustrates a mixin which provides a generic association │ │ │ │ using a single target table and a single association table, │ │ │ │ referred to by all parent tables. The association table │ │ │ │ contains a “discriminator” column which determines what type of │ │ │ │ parent object associates to each particular row in the association │ │ │ │ table.
│ │ │ │generic_fk.py - Illustrates a so-called “generic foreign key”, in a similar fashion │ │ │ │ to that of popular frameworks such as Django, ROR, etc. This │ │ │ │ approach bypasses standard referential integrity │ │ │ │ practices, in that the “foreign key” column is not actually │ │ │ │ constrained to refer to any particular table; instead, │ │ │ │ in-application logic is used to determine which table is referenced.
│ │ │ │table_per_related.py - Illustrates a generic association which persists association │ │ │ │ -objects within individual tables, each one generated to persist │ │ │ │ -those objects on behalf of a particular parent class.
│ │ │ │ -Large collection example.
│ │ │ │Illustrates the options to use with │ │ │ │ @@ -500,33 +500,33 @@ │ │ │ │
See also
│ │ │ │ │ │ │ │Listing of files:
large_resultsets.py - In this series of tests, we are looking at time to load a large number │ │ │ │ -of very small and simple rows.
│ │ │ │ -bulk_updates.py - This series of tests will illustrate different ways to UPDATE a large number │ │ │ │ -of rows in bulk (under construction! there’s just one test at the moment)
│ │ │ │ -short_selects.py - This series of tests illustrates different ways to SELECT a single │ │ │ │ -record by primary key
│ │ │ │ -bulk_inserts.py - This series of tests illustrates different ways to INSERT a large number │ │ │ │ of rows in bulk.
│ │ │ │__main__.py - Allows the examples/performance package to be run as a script.
│ │ │ │ +short_selects.py - This series of tests illustrates different ways to SELECT a single │ │ │ │ +record by primary key
│ │ │ │single_inserts.py - In this series of tests, we’re looking at a method that inserts a row │ │ │ │ within a distinct transaction, and afterwards returns to essentially a │ │ │ │ “closed” state. This would be analogous to an API call that starts up │ │ │ │ a database connection, inserts the row, commits and closes.
│ │ │ │bulk_updates.py - This series of tests will illustrate different ways to UPDATE a large number │ │ │ │ +of rows in bulk (under construction! there’s just one test at the moment)
│ │ │ │ +large_resultsets.py - In this series of tests, we are looking at time to load a large number │ │ │ │ +of very small and simple rows.
│ │ │ │ +__main__.py - Allows the examples/performance package to be run as a script.
│ │ │ │ +This is the default form of run:
│ │ │ │$ python -m examples.performance single_inserts
│ │ │ │ @@ -668,22 +668,22 @@
│ │ │ │
│ │ │ │
│ │ │ │ Relationship Join Conditions¶
│ │ │ │ Examples of various relationship() configurations,
│ │ │ │ which make use of the primaryjoin argument to compose special types
│ │ │ │ of join conditions.
│ │ │ │ Listing of files:
│ │ │ │ -cast.py - Illustrate a relationship() that joins two columns where those
│ │ │ │ -columns are not of the same type, and a CAST must be used on the SQL
│ │ │ │ -side in order to match them.
│ │ │ │ -threeway.py - Illustrate a “three way join” - where a primary table joins to a remote
│ │ │ │ table via an association table, but then the primary table also needs
│ │ │ │ to refer to some columns in the remote table directly.
│ │ │ │ cast.py - Illustrate a relationship() that joins two columns where those
│ │ │ │ +columns are not of the same type, and a CAST must be used on the SQL
│ │ │ │ +side in order to match them.
│ │ │ │ +
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │ Space Invaders¶
│ │ │ │ A Space Invaders game using SQLite as the state machine.
│ │ │ │ Originally developed in 2012. Adapted to work in Python 3.
│ │ │ │ @@ -830,31 +830,31 @@
│ │ │ │ Several examples that illustrate the technique of intercepting changes
│ │ │ │ that would be first interpreted as an UPDATE on a row, and instead turning
│ │ │ │ it into an INSERT of a new row, leaving the previous row intact as
│ │ │ │ a historical version.
│ │ │ │ Compare to the Versioning with a History Table example which writes a
│ │ │ │ history row to a separate history table.
│ │ │ │ Listing of files:
│ │ │ │ -versioned_rows_w_versionid.py - Illustrates a method to intercept changes on objects, turning
│ │ │ │ -an UPDATE statement on a single row into an INSERT statement, so that a new
│ │ │ │ -row is inserted with the new data, keeping the old row intact.
│ │ │ │ -versioned_rows.py - Illustrates a method to intercept changes on objects, turning
│ │ │ │ an UPDATE statement on a single row into an INSERT statement, so that a new
│ │ │ │ row is inserted with the new data, keeping the old row intact.
│ │ │ │ versioned_map.py - A variant of the versioned_rows example built around the
│ │ │ │ concept of a “vertical table” structure, like those illustrated in
│ │ │ │ Vertical Attribute Mapping examples.
│ │ │ │ versioned_update_old_row.py - Illustrates the same UPDATE into INSERT technique of versioned_rows.py,
│ │ │ │ but also emits an UPDATE on the old row to affect a change in timestamp.
│ │ │ │ Also includes a SessionEvents.do_orm_execute() hook to limit queries
│ │ │ │ to only the most recent version.
│ │ │ │ versioned_rows_w_versionid.py - Illustrates a method to intercept changes on objects, turning
│ │ │ │ +an UPDATE statement on a single row into an INSERT statement, so that a new
│ │ │ │ +row is inserted with the new data, keeping the old row intact.
│ │ │ │ +
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │ Vertical Attribute Mapping¶
│ │ │ │ Illustrates “vertical table” mappings.
│ │ │ │ @@ -896,40 +896,40 @@
│ │ │ │
│ │ │ │ Basic Inheritance Mappings¶
│ │ │ │ Working examples of single-table, joined-table, and concrete-table
│ │ │ │ inheritance as described in Mapping Class Inheritance Hierarchies.
│ │ │ │ Listing of files:
│ │ │ │ concrete.py - Concrete-table (table-per-class) inheritance example.
│ │ │ │ joined.py - Joined-table (table-per-subclass) inheritance example.
│ │ │ │ -single.py - Single-table (table-per-hierarchy) inheritance example.
│ │ │ │ joined.py - Joined-table (table-per-subclass) inheritance example.
│ │ │ │ +
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │ Special APIs¶
│ │ │ │
│ │ │ │ Attribute Instrumentation¶
│ │ │ │ Examples illustrating modifications to SQLAlchemy’s attribute management
│ │ │ │ system.
│ │ │ │ Listing of files:
│ │ │ │ +custom_management.py - Illustrates customized class instrumentation, using
│ │ │ │ +the sqlalchemy.ext.instrumentation extension package.
│ │ │ │ +listen_for_events.py - Illustrates how to attach events to all instrumented attributes
│ │ │ │ and listen for change events.
│ │ │ │ active_column_defaults.py - Illustrates use of the AttributeEvents.init_scalar()
│ │ │ │ event, in conjunction with Core column defaults to provide
│ │ │ │ ORM objects that automatically produce the default value
│ │ │ │ when an un-set attribute is accessed.
│ │ │ │ custom_management.py - Illustrates customized class instrumentation, using
│ │ │ │ -the sqlalchemy.ext.instrumentation extension package.
│ │ │ │ -
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │ Horizontal Sharding¶
│ │ │ │ A basic example of using the SQLAlchemy Sharding API.
│ │ │ │ Sharding refers to horizontally scaling data across multiple
│ │ │ │ @@ -958,20 +958,20 @@
│ │ │ │
The construction of generic sharding routines is an ambitious approach
│ │ │ │ to the issue of organizing instances among multiple databases. For a
│ │ │ │ more plain-spoken alternative, the “distinct entity” approach
│ │ │ │ is a simple method of assigning objects to different tables (and potentially
│ │ │ │ database nodes) in an explicit way - described on the wiki at
│ │ │ │ EntityName.
│ │ │ │ Listing of files:
│ │ │ │ -separate_schema_translates.py - Illustrates sharding using a single database with multiple schemas,
│ │ │ │ -where a different “schema_translates_map” can be used for each shard.
│ │ │ │ -separate_tables.py - Illustrates sharding using a single SQLite database, that will however
│ │ │ │ have multiple tables using a naming convention.
│ │ │ │ separate_schema_translates.py - Illustrates sharding using a single database with multiple schemas,
│ │ │ │ +where a different “schema_translates_map” can be used for each shard.
│ │ │ │ +separate_databases.py - Illustrates sharding using distinct SQLite databases.
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │ @@ -984,19 +984,19 @@
│ │ │ │ object.
│ │ │ │ Examples include demonstrations of the with_loader_criteria()
│ │ │ │ option as well as the SessionEvents.do_orm_execute() hook.
│ │ │ │ As of SQLAlchemy 1.4, the Query construct is unified
│ │ │ │ with the Select construct, so that these two objects
│ │ │ │ are mostly the same.
│ │ │ │ Listing of files:
│ │ │ │ -filter_public.py - Illustrates a global criteria applied to entities of a particular type.
│ │ │ │ -temporal_range.py - Illustrates a custom per-query criteria that will be applied
│ │ │ │ to selected entities.
│ │ │ │ filter_public.py - Illustrates a global criteria applied to entities of a particular type.
│ │ │ │ +
│ │ │ │
│ │ │ │
│ │ │ │
│ │ │ │ Dogpile Caching¶
│ │ │ │ Illustrates how to embed
│ │ │ │ dogpile.cache
│ │ │ │ ├── html2text {}
│ │ │ │ │ @@ -105,35 +105,35 @@
│ │ │ │ │ Listing of files:
│ │ │ │ │ * _a_d_j_a_c_e_n_c_y___l_i_s_t_._p_y
│ │ │ │ │ ******** AAssssoocciiaattiioonnss_?¶ ********
│ │ │ │ │ Examples illustrating the usage of the “association object” pattern, where an
│ │ │ │ │ intermediary class mediates the relationship between two classes that are
│ │ │ │ │ associated in a many-to-many pattern.
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _d_i_c_t___o_f___s_e_t_s___w_i_t_h___d_e_f_a_u_l_t_._p_y - An advanced association proxy example
│ │ │ │ │ - which illustrates nesting of association proxies to produce multi-level
│ │ │ │ │ - Python collections, in this case a dictionary with string keys and sets
│ │ │ │ │ - of integers as values, which conceal the underlying mapped classes.
│ │ │ │ │ + * _p_r_o_x_i_e_d___a_s_s_o_c_i_a_t_i_o_n_._p_y - Same example as basic_association, adding in
│ │ │ │ │ + usage of _s_q_l_a_l_c_h_e_m_y_._e_x_t_._a_s_s_o_c_i_a_t_i_o_n_p_r_o_x_y to make explicit references to
│ │ │ │ │ + OrderItem optional.
│ │ │ │ │ +_d_i_c_t___o_f___s_e_t_s___w_i_t_h___d_e_f_a_u_l_t_._p_y - An advanced association proxy example which
│ │ │ │ │ +illustrates nesting of association proxies to produce multi-level Python
│ │ │ │ │ +collections, in this case a dictionary with string keys and sets of integers as
│ │ │ │ │ +values, which conceal the underlying mapped classes.
│ │ │ │ │ _b_a_s_i_c___a_s_s_o_c_i_a_t_i_o_n_._p_y - Illustrate a many-to-many relationship between an
│ │ │ │ │ “Order” and a collection of “Item” objects, associating a purchase price with
│ │ │ │ │ each via an association object called “OrderItem”
│ │ │ │ │ -_p_r_o_x_i_e_d___a_s_s_o_c_i_a_t_i_o_n_._p_y - Same example as basic_association, adding in usage of
│ │ │ │ │ -_s_q_l_a_l_c_h_e_m_y_._e_x_t_._a_s_s_o_c_i_a_t_i_o_n_p_r_o_x_y to make explicit references to OrderItem
│ │ │ │ │ -optional.
│ │ │ │ │ ******** AAssyynncciioo IInntteeggrraattiioonn_?¶ ********
│ │ │ │ │ Examples illustrating the asyncio engine feature of SQLAlchemy.
│ │ │ │ │ Listing of files:
│ │ │ │ │ * _b_a_s_i_c_._p_y - Illustrates the asyncio engine / connection interface.
│ │ │ │ │ -_g_r_e_e_n_l_e_t___o_r_m_._p_y - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession
│ │ │ │ │ -object for asynchronous ORM use, including the optional run_sync() method.
│ │ │ │ │ +_a_s_y_n_c___o_r_m_._p_y - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession
│ │ │ │ │ +object for asynchronous ORM use.
│ │ │ │ │ _g_a_t_h_e_r___o_r_m___s_t_a_t_e_m_e_n_t_s_._p_y - Illustrates how to run many statements concurrently
│ │ │ │ │ using asyncio.gather() along many asyncio database connections, merging ORM
│ │ │ │ │ results into a single AsyncSession.
│ │ │ │ │ -_a_s_y_n_c___o_r_m_._p_y - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession
│ │ │ │ │ -object for asynchronous ORM use.
│ │ │ │ │ +_g_r_e_e_n_l_e_t___o_r_m_._p_y - Illustrates use of the sqlalchemy.ext.asyncio.AsyncSession
│ │ │ │ │ +object for asynchronous ORM use, including the optional run_sync() method.
│ │ │ │ │ ******** DDiirreecctteedd GGrraapphhss_?¶ ********
│ │ │ │ │ An example of persistence for a directed graph structure. The graph is stored
│ │ │ │ │ as a collection of edges, each referencing both a “lower” and an “upper” node
│ │ │ │ │ in a table of nodes. Basic persistence and querying for lower- and upper-
│ │ │ │ │ neighbors are illustrated:
│ │ │ │ │ n2 = Node(2)
│ │ │ │ │ n5 = Node(5)
│ │ │ │ │ @@ -155,31 +155,31 @@
│ │ │ │ │ Supplier, both subclassing the HasAddresses mixin, which ensures that the
│ │ │ │ │ parent class is provided with an addresses collection which contains Address
│ │ │ │ │ objects.
│ │ │ │ │ The _d_i_s_c_r_i_m_i_n_a_t_o_r___o_n___a_s_s_o_c_i_a_t_i_o_n_._p_y and _g_e_n_e_r_i_c___f_k_._p_y scripts are modernized
│ │ │ │ │ versions of recipes presented in the 2007 blog post _P_o_l_y_m_o_r_p_h_i_c_ _A_s_s_o_c_i_a_t_i_o_n_s
│ │ │ │ │ _w_i_t_h_ _S_Q_L_A_l_c_h_e_m_y.
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _d_i_s_c_r_i_m_i_n_a_t_o_r___o_n___a_s_s_o_c_i_a_t_i_o_n_._p_y - Illustrates a mixin which provides a
│ │ │ │ │ - generic association using a single target table and a single association
│ │ │ │ │ - table, referred to by all parent tables. The association table contains a
│ │ │ │ │ - “discriminator” column which determines what type of parent object
│ │ │ │ │ - associates to each particular row in the association table.
│ │ │ │ │ + * _t_a_b_l_e___p_e_r___r_e_l_a_t_e_d_._p_y - Illustrates a generic association which persists
│ │ │ │ │ + association objects within individual tables, each one generated to
│ │ │ │ │ + persist those objects on behalf of a particular parent class.
│ │ │ │ │ +_d_i_s_c_r_i_m_i_n_a_t_o_r___o_n___a_s_s_o_c_i_a_t_i_o_n_._p_y - Illustrates a mixin which provides a generic
│ │ │ │ │ +association using a single target table and a single association table,
│ │ │ │ │ +referred to by all parent tables. The association table contains a
│ │ │ │ │ +“discriminator” column which determines what type of parent object associates
│ │ │ │ │ +to each particular row in the association table.
│ │ │ │ │ _t_a_b_l_e___p_e_r___a_s_s_o_c_i_a_t_i_o_n_._p_y - Illustrates a mixin which provides a generic
│ │ │ │ │ association via a individually generated association tables for each parent
│ │ │ │ │ class. The associated objects themselves are persisted in a single table shared
│ │ │ │ │ among all parents.
│ │ │ │ │ _g_e_n_e_r_i_c___f_k_._p_y - Illustrates a so-called “generic foreign key”, in a similar
│ │ │ │ │ fashion to that of popular frameworks such as Django, ROR, etc. This approach
│ │ │ │ │ bypasses standard referential integrity practices, in that the “foreign key”
│ │ │ │ │ column is not actually constrained to refer to any particular table; instead,
│ │ │ │ │ in-application logic is used to determine which table is referenced.
│ │ │ │ │ -_t_a_b_l_e___p_e_r___r_e_l_a_t_e_d_._p_y - Illustrates a generic association which persists
│ │ │ │ │ -association objects within individual tables, each one generated to persist
│ │ │ │ │ -those objects on behalf of a particular parent class.
│ │ │ │ │ ******** LLaarrggee CCoolllleeccttiioonnss_?¶ ********
│ │ │ │ │ Large collection example.
│ │ │ │ │ Illustrates the options to use with _r_e_l_a_t_i_o_n_s_h_i_p_(_) when the list of related
│ │ │ │ │ objects is very large, including:
│ │ │ │ │ * “dynamic” relationships which query slices of data as accessed
│ │ │ │ │ * how to use ON DELETE CASCADE in conjunction with passive_deletes=True to
│ │ │ │ │ greatly improve the performance of related collection deletion.
│ │ │ │ │ @@ -236,28 +236,28 @@
│ │ │ │ │ $ python -m examples.performance bulk_inserts \
│ │ │ │ │ --dburl mysql+mysqldb://scott:tiger@localhost/test \
│ │ │ │ │ --profile --num 1000
│ │ │ │ │ See also
│ │ │ │ │ _H_o_w_ _c_a_n_ _I_ _p_r_o_f_i_l_e_ _a_ _S_Q_L_A_l_c_h_e_m_y_ _p_o_w_e_r_e_d_ _a_p_p_l_i_c_a_t_i_o_n_?
│ │ │ │ │ ****** FFiillee LLiissttiinngg_?¶ ******
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _l_a_r_g_e___r_e_s_u_l_t_s_e_t_s_._p_y - In this series of tests, we are looking at time to
│ │ │ │ │ - load a large number of very small and simple rows.
│ │ │ │ │ -_b_u_l_k___u_p_d_a_t_e_s_._p_y - This series of tests will illustrate different ways to UPDATE
│ │ │ │ │ -a large number of rows in bulk (under construction! there’s just one test at
│ │ │ │ │ -the moment)
│ │ │ │ │ + * _b_u_l_k___i_n_s_e_r_t_s_._p_y - This series of tests illustrates different ways to
│ │ │ │ │ + INSERT a large number of rows in bulk.
│ │ │ │ │ _s_h_o_r_t___s_e_l_e_c_t_s_._p_y - This series of tests illustrates different ways to SELECT a
│ │ │ │ │ single record by primary key
│ │ │ │ │ -_b_u_l_k___i_n_s_e_r_t_s_._p_y - This series of tests illustrates different ways to INSERT a
│ │ │ │ │ -large number of rows in bulk.
│ │ │ │ │ -_____m_a_i_n_____._p_y - Allows the examples/performance package to be run as a script.
│ │ │ │ │ _s_i_n_g_l_e___i_n_s_e_r_t_s_._p_y - In this series of tests, we’re looking at a method that
│ │ │ │ │ inserts a row within a distinct transaction, and afterwards returns to
│ │ │ │ │ essentially a “closed” state. This would be analogous to an API call that
│ │ │ │ │ starts up a database connection, inserts the row, commits and closes.
│ │ │ │ │ +_b_u_l_k___u_p_d_a_t_e_s_._p_y - This series of tests will illustrate different ways to UPDATE
│ │ │ │ │ +a large number of rows in bulk (under construction! there’s just one test at
│ │ │ │ │ +the moment)
│ │ │ │ │ +_l_a_r_g_e___r_e_s_u_l_t_s_e_t_s_._p_y - In this series of tests, we are looking at time to load a
│ │ │ │ │ +large number of very small and simple rows.
│ │ │ │ │ +_____m_a_i_n_____._p_y - Allows the examples/performance package to be run as a script.
│ │ │ │ │ ****** RRuunnnniinngg aallll tteessttss wwiitthh ttiimmee_?¶ ******
│ │ │ │ │ This is the default form of run:
│ │ │ │ │ $ python -m examples.performance single_inserts
│ │ │ │ │ Tests to run: test_orm_commit, test_bulk_save,
│ │ │ │ │ test_bulk_insert_dictionaries, test_core,
│ │ │ │ │ test_core_query_caching, test_dbapi_raw_w_connect,
│ │ │ │ │ test_dbapi_raw_w_pool
│ │ │ │ │ @@ -394,20 +394,20 @@
│ │ │ │ │ total time 2.754592 sec
│ │ │ │ │ test_subqueryload : load everything, subquery eager loading. (1000 iterations);
│ │ │ │ │ total time 2.977696 sec
│ │ │ │ │ ******** RReellaattiioonnsshhiipp JJooiinn CCoonnddiittiioonnss_?¶ ********
│ │ │ │ │ Examples of various _r_e_l_a_t_i_o_n_s_h_i_p_(_) configurations, which make use of the
│ │ │ │ │ primaryjoin argument to compose special types of join conditions.
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _c_a_s_t_._p_y - Illustrate a _r_e_l_a_t_i_o_n_s_h_i_p_(_) that joins two columns where those
│ │ │ │ │ - columns are not of the same type, and a CAST must be used on the SQL side
│ │ │ │ │ - in order to match them.
│ │ │ │ │ -_t_h_r_e_e_w_a_y_._p_y - Illustrate a “three way join” - where a primary table joins to a
│ │ │ │ │ -remote table via an association table, but then the primary table also needs to
│ │ │ │ │ -refer to some columns in the remote table directly.
│ │ │ │ │ + * _t_h_r_e_e_w_a_y_._p_y - Illustrate a “three way join” - where a primary table joins
│ │ │ │ │ + to a remote table via an association table, but then the primary table
│ │ │ │ │ + also needs to refer to some columns in the remote table directly.
│ │ │ │ │ +_c_a_s_t_._p_y - Illustrate a _r_e_l_a_t_i_o_n_s_h_i_p_(_) that joins two columns where those
│ │ │ │ │ +columns are not of the same type, and a CAST must be used on the SQL side in
│ │ │ │ │ +order to match them.
│ │ │ │ │ ******** SSppaaccee IInnvvaaddeerrss_?¶ ********
│ │ │ │ │ A Space Invaders game using SQLite as the state machine.
│ │ │ │ │ Originally developed in 2012. Adapted to work in Python 3.
│ │ │ │ │ Runs in a textual console using ASCII art.
│ │ │ │ │ [../_images/space_invaders.jpg]
│ │ │ │ │ To run:
│ │ │ │ │ python -m examples.space_invaders.space_invaders
│ │ │ │ │ @@ -521,28 +521,27 @@
│ │ │ │ │ Several examples that illustrate the technique of intercepting changes that
│ │ │ │ │ would be first interpreted as an UPDATE on a row, and instead turning it into
│ │ │ │ │ an INSERT of a new row, leaving the previous row intact as a historical
│ │ │ │ │ version.
│ │ │ │ │ Compare to the _V_e_r_s_i_o_n_i_n_g_ _w_i_t_h_ _a_ _H_i_s_t_o_r_y_ _T_a_b_l_e example which writes a history
│ │ │ │ │ row to a separate history table.
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _v_e_r_s_i_o_n_e_d___r_o_w_s___w___v_e_r_s_i_o_n_i_d_._p_y - Illustrates a method to intercept changes
│ │ │ │ │ - on objects, turning an UPDATE statement on a single row into an INSERT
│ │ │ │ │ - statement, so that a new row is inserted with the new data, keeping the
│ │ │ │ │ - old row intact.
│ │ │ │ │ -_v_e_r_s_i_o_n_e_d___r_o_w_s_._p_y - Illustrates a method to intercept changes on objects,
│ │ │ │ │ -turning an UPDATE statement on a single row into an INSERT statement, so that a
│ │ │ │ │ -new row is inserted with the new data, keeping the old row intact.
│ │ │ │ │ + * _v_e_r_s_i_o_n_e_d___r_o_w_s_._p_y - Illustrates a method to intercept changes on objects,
│ │ │ │ │ + turning an UPDATE statement on a single row into an INSERT statement, so
│ │ │ │ │ + that a new row is inserted with the new data, keeping the old row intact.
│ │ │ │ │ _v_e_r_s_i_o_n_e_d___m_a_p_._p_y - A variant of the versioned_rows example built around the
│ │ │ │ │ concept of a “vertical table” structure, like those illustrated in _V_e_r_t_i_c_a_l
│ │ │ │ │ _A_t_t_r_i_b_u_t_e_ _M_a_p_p_i_n_g examples.
│ │ │ │ │ _v_e_r_s_i_o_n_e_d___u_p_d_a_t_e___o_l_d___r_o_w_._p_y - Illustrates the same UPDATE into INSERT technique
│ │ │ │ │ of versioned_rows.py, but also emits an UPDATE on the oolldd row to affect a
│ │ │ │ │ change in timestamp. Also includes a _S_e_s_s_i_o_n_E_v_e_n_t_s_._d_o___o_r_m___e_x_e_c_u_t_e_(_) hook to
│ │ │ │ │ limit queries to only the most recent version.
│ │ │ │ │ +_v_e_r_s_i_o_n_e_d___r_o_w_s___w___v_e_r_s_i_o_n_i_d_._p_y - Illustrates a method to intercept changes on
│ │ │ │ │ +objects, turning an UPDATE statement on a single row into an INSERT statement,
│ │ │ │ │ +so that a new row is inserted with the new data, keeping the old row intact.
│ │ │ │ │ ******** VVeerrttiiccaall AAttttrriibbuuttee MMaappppiinngg_?¶ ********
│ │ │ │ │ Illustrates “vertical table” mappings.
│ │ │ │ │ A “vertical table” refers to a technique where individual attributes of an
│ │ │ │ │ object are stored as distinct rows in a table. The “vertical table” technique
│ │ │ │ │ is used to persist objects which can have a varied set of attributes, at the
│ │ │ │ │ expense of simple query control and brevity. It is commonly found in content/
│ │ │ │ │ document management systems in order to represent user-created structures
│ │ │ │ │ @@ -570,28 +569,28 @@
│ │ │ │ │ dictionary.
│ │ │ │ │ ********** IInnhheerriittaannccee MMaappppiinngg RReecciippeess_?¶ **********
│ │ │ │ │ ******** BBaassiicc IInnhheerriittaannccee MMaappppiinnggss_?¶ ********
│ │ │ │ │ Working examples of single-table, joined-table, and concrete-table inheritance
│ │ │ │ │ as described in _M_a_p_p_i_n_g_ _C_l_a_s_s_ _I_n_h_e_r_i_t_a_n_c_e_ _H_i_e_r_a_r_c_h_i_e_s.
│ │ │ │ │ Listing of files:
│ │ │ │ │ * _c_o_n_c_r_e_t_e_._p_y - Concrete-table (table-per-class) inheritance example.
│ │ │ │ │ -_j_o_i_n_e_d_._p_y - Joined-table (table-per-subclass) inheritance example.
│ │ │ │ │ _s_i_n_g_l_e_._p_y - Single-table (table-per-hierarchy) inheritance example.
│ │ │ │ │ +_j_o_i_n_e_d_._p_y - Joined-table (table-per-subclass) inheritance example.
│ │ │ │ │ ********** SSppeecciiaall AAPPIIss_?¶ **********
│ │ │ │ │ ******** AAttttrriibbuuttee IInnssttrruummeennttaattiioonn_?¶ ********
│ │ │ │ │ Examples illustrating modifications to SQLAlchemy’s attribute management
│ │ │ │ │ system.
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _l_i_s_t_e_n___f_o_r___e_v_e_n_t_s_._p_y - Illustrates how to attach events to all
│ │ │ │ │ - instrumented attributes and listen for change events.
│ │ │ │ │ + * _c_u_s_t_o_m___m_a_n_a_g_e_m_e_n_t_._p_y - Illustrates customized class instrumentation,
│ │ │ │ │ + using the _s_q_l_a_l_c_h_e_m_y_._e_x_t_._i_n_s_t_r_u_m_e_n_t_a_t_i_o_n extension package.
│ │ │ │ │ +_l_i_s_t_e_n___f_o_r___e_v_e_n_t_s_._p_y - Illustrates how to attach events to all instrumented
│ │ │ │ │ +attributes and listen for change events.
│ │ │ │ │ _a_c_t_i_v_e___c_o_l_u_m_n___d_e_f_a_u_l_t_s_._p_y - Illustrates use of the _A_t_t_r_i_b_u_t_e_E_v_e_n_t_s_._i_n_i_t___s_c_a_l_a_r
│ │ │ │ │ _(_) event, in conjunction with Core column defaults to provide ORM objects that
│ │ │ │ │ automatically produce the default value when an un-set attribute is accessed.
│ │ │ │ │ -_c_u_s_t_o_m___m_a_n_a_g_e_m_e_n_t_._p_y - Illustrates customized class instrumentation, using the
│ │ │ │ │ -_s_q_l_a_l_c_h_e_m_y_._e_x_t_._i_n_s_t_r_u_m_e_n_t_a_t_i_o_n extension package.
│ │ │ │ │ ******** HHoorriizzoonnttaall SShhaarrddiinngg_?¶ ********
│ │ │ │ │ A basic example of using the SQLAlchemy Sharding API. Sharding refers to
│ │ │ │ │ horizontally scaling data across multiple databases.
│ │ │ │ │ The basic components of a “sharded” mapping are:
│ │ │ │ │ * multiple _E_n_g_i_n_e instances, each assigned a “shard id”. These _E_n_g_i_n_e
│ │ │ │ │ instances may refer to different databases, or different schemas /
│ │ │ │ │ accounts within the same database, or they can even be differentiated
│ │ │ │ │ @@ -612,34 +611,34 @@
│ │ │ │ │ attempt to determine a single shard being requested.
│ │ │ │ │ The construction of generic sharding routines is an ambitious approach to the
│ │ │ │ │ issue of organizing instances among multiple databases. For a more plain-spoken
│ │ │ │ │ alternative, the “distinct entity” approach is a simple method of assigning
│ │ │ │ │ objects to different tables (and potentially database nodes) in an explicit way
│ │ │ │ │ - described on the wiki at _E_n_t_i_t_y_N_a_m_e.
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _s_e_p_a_r_a_t_e___s_c_h_e_m_a___t_r_a_n_s_l_a_t_e_s_._p_y - Illustrates sharding using a single
│ │ │ │ │ - database with multiple schemas, where a different “schema_translates_map”
│ │ │ │ │ - can be used for each shard.
│ │ │ │ │ -_s_e_p_a_r_a_t_e___t_a_b_l_e_s_._p_y - Illustrates sharding using a single SQLite database, that
│ │ │ │ │ -will however have multiple tables using a naming convention.
│ │ │ │ │ + * _s_e_p_a_r_a_t_e___t_a_b_l_e_s_._p_y - Illustrates sharding using a single SQLite database,
│ │ │ │ │ + that will however have multiple tables using a naming convention.
│ │ │ │ │ +_s_e_p_a_r_a_t_e___s_c_h_e_m_a___t_r_a_n_s_l_a_t_e_s_._p_y - Illustrates sharding using a single database
│ │ │ │ │ +with multiple schemas, where a different “schema_translates_map” can be used
│ │ │ │ │ +for each shard.
│ │ │ │ │ _s_e_p_a_r_a_t_e___d_a_t_a_b_a_s_e_s_._p_y - Illustrates sharding using distinct SQLite databases.
│ │ │ │ │ ********** EExxtteennddiinngg tthhee OORRMM_?¶ **********
│ │ │ │ │ ******** OORRMM QQuueerryy EEvveennttss_?¶ ********
│ │ │ │ │ Recipes which illustrate augmentation of ORM SELECT behavior as used by
│ │ │ │ │ _S_e_s_s_i_o_n_._e_x_e_c_u_t_e_(_) with _2_._0_ _s_t_y_l_e use of _s_e_l_e_c_t_(_), as well as the _1_._x_ _s_t_y_l_e
│ │ │ │ │ _Q_u_e_r_y object.
│ │ │ │ │ Examples include demonstrations of the _w_i_t_h___l_o_a_d_e_r___c_r_i_t_e_r_i_a_(_) option as well as
│ │ │ │ │ the _S_e_s_s_i_o_n_E_v_e_n_t_s_._d_o___o_r_m___e_x_e_c_u_t_e_(_) hook.
│ │ │ │ │ As of SQLAlchemy 1.4, the _Q_u_e_r_y construct is unified with the _S_e_l_e_c_t construct,
│ │ │ │ │ so that these two objects are mostly the same.
│ │ │ │ │ Listing of files:
│ │ │ │ │ - * _f_i_l_t_e_r___p_u_b_l_i_c_._p_y - Illustrates a global criteria applied to entities of a
│ │ │ │ │ - particular type.
│ │ │ │ │ -_t_e_m_p_o_r_a_l___r_a_n_g_e_._p_y - Illustrates a custom per-query criteria that will be
│ │ │ │ │ -applied to selected entities.
│ │ │ │ │ + * _t_e_m_p_o_r_a_l___r_a_n_g_e_._p_y - Illustrates a custom per-query criteria that will be
│ │ │ │ │ + applied to selected entities.
│ │ │ │ │ +_f_i_l_t_e_r___p_u_b_l_i_c_._p_y - Illustrates a global criteria applied to entities of a
│ │ │ │ │ +particular type.
│ │ │ │ │ ******** DDooggppiillee CCaacchhiinngg_?¶ ********
│ │ │ │ │ Illustrates how to embed _d_o_g_p_i_l_e_._c_a_c_h_e functionality with ORM queries, allowing
│ │ │ │ │ full cache control as well as the ability to pull “lazy loaded” attributes from
│ │ │ │ │ long term cache.
│ │ │ │ │ In this demo, the following techniques are illustrated:
│ │ │ │ │ * Using the _S_e_s_s_i_o_n_E_v_e_n_t_s_._d_o___o_r_m___e_x_e_c_u_t_e_(_) event hook
│ │ │ │ │ * Basic technique of circumventing _S_e_s_s_i_o_n_._e_x_e_c_u_t_e_(_) to pull from a custom