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.. currentmodule:: apsw.ext
Various interesting and useful bits of functionality
====================================================
You need to import `apsw.ext` to use this module.
Pretty printing
---------------
:meth:`format_query_table` makes nicely formatted query output - see
the :ref:`the example <example_format_query>`.
Logging and tracebacks
----------------------
You can use :meth:`log_sqlite` to forward SQLite log messages
to the :mod:`logging` module.
:meth:`print_augmented_traceback` prints an exception the usual way
but also includes local variables, which :ref:`APSW includes
<augmentedstacktraces>` to make debugging quicker and easier.
Virtual Tables
--------------
Use :meth:`index_info_to_dict` to get :class:`apsw.IndexInfo`
in an easier to print and work with format.
Use :meth:`make_virtual_module` to easily turn a Python function
into a virtual table source.
:meth:`generate_series` and :meth:`generate_series_sqlite` provide
`generate_series <https://sqlite.org/series.html>`__.
Accessing result rows by column name
------------------------------------
See :ref:`the example <example_colnames>`.
Use :class:`apsw.ext.DataClassRowFactory` as a
:attr:`apsw.Connection.row_trace` for an entire connection, or
:attr:`apsw.Cursor.row_trace` for a specific cursor.
.. _typeconversion:
Converting types into and out of SQLite
---------------------------------------
SQLite only stores and returns 5 types:
* None
* int
* float
* str
* bytes
Use :class:`TypesConverterCursorFactory` as
:attr:`apsw.Connection.cursor_factory` to adapt values going into
SQLite, and convert them coming out. See :ref:`the example
<example_type_conversion>`.
To convert values going into SQLite, do either of:
* Inherit from :class:`apsw.ext.SQLiteTypeAdapter` and define a
*to_sqlite_value* method on the class
* Call :meth:`TypesConverterCursorFactory.register_adapter` with the
type and a adapter function
To adapt values coming out of SQLite:
* Call :meth:`TypesConverterCursorFactory.register_converter` with the
exact type string in the table and a converter function
Detailed Query Information
--------------------------
SQLite can provide lots of information about queries. The
:meth:`~apsw.ext.query_info` function can gather them up
for you. This includes:
* **readonly** if the query makes no direct changes
* **first_query** if multiple queries are provided
* **actions** which databases, tables, columns, functions, views etc
are referenced - see `actions
<https://sqlite.org/c3ref/c_alter_table.html>`__
* **query_plan** which indices, tables scans etc are used to find the
query results - see `query plans <https://sqlite.org/eqp.html>`__
* **explain** for the low level steps taken inside SQLite - see
`SQLite bytecode <https://sqlite.org/opcode.html>`__
See :ref:`the example <example_query_details>`.
API Reference
-------------
.. automodule:: apsw.ext
:synopsis: Various interesting and useful bits of functionality
:members:
:undoc-members:
:member-order: bysource
:special-members: __call__
|
