Convenience wrapper around psycopg2.ConnectionPool and Cursor. More...

Inheritance diagram for dblite.engines.postgres.Database:

Public Member Functions
def	__init__ (self, opts, **kwargs)
	Creates a new Database instance for Postgres. More...

def	__enter__ (self)
	Context manager entry, opens database if not already open, returns Database object. More...

def	__exit__ (self, exc_type, exc_val, exc_trace)
	Context manager exit, closes database and any pending transactions if open. More...

def	close (self, commit=None)
	Closes the database and any pending transactions, if open. More...

def	execute (self, sql, args=())
	Executes SQL statement, returns psycopg cursor. More...

def	executemany (self, sql, args)
	Executes the SQL statement against all parameter sequences. More...

def	executescript (self, sql)
	Executes the SQL as script of any number of statements. More...

def	init_pool (cls, db, minconn=POOL_SIZE[0], maxconn=POOL_SIZE[1], **kwargs)
	Initializes connection pool for Database if not already initialized. More...

def	make_cursor (self, commit=False, autocommit=False, schema=None, lazy=False, itersize=None)
	Context manager for psycopg connection cursor. More...

def	open (self)
	Opens database connection if not already open. More...

def	transaction (self, commit=True, exclusive=False, **kwargs)
	Returns a transaction context manager. More...

Public Member Functions inherited from dblite.api.Database
def	__del__ (self)
	Closes the database, if open. More...

Public Member Functions inherited from dblite.api.Queryable
def	delete (self, table, where=(), **kwargs)
	Convenience wrapper for database DELETE, returns affected row count. More...

def	fetchall (self, table, cols="", where=(), group=(), order=(), limit=(), *kwargs)
	Convenience wrapper for database SELECT and fetch all. More...

def	fetchone (self, table, cols="", where=(), group=(), order=(), limit=(), *kwargs)
	Convenience wrapper for database SELECT and fetch one. More...

def	select (self, table, cols="", where=(), group=(), order=(), limit=(), *kwargs)
	Convenience wrapper for database SELECT, returns database cursor. More...

def	update (self, table, values, where=(), **kwargs)
	Convenience wrapper for database UPDATE, returns affected row count. More...

Public Member Functions inherited from dblite.engines.postgres.Queryable
def	insert (self, table, values=(), **kwargs)
	Convenience wrapper for database INSERT, returns inserted row ID. More...

def	insertmany (self, table, rows=(), **kwargs)
	Convenience wrapper for database multiple INSERTs, returns list of inserted row IDs. More...

def	makeSQL (self, action, table, cols="*", where=(), group=(), order=(), limit=(), values=(), kwargs=None)
	Returns (SQL statement string, parameter dict). More...

def	quote (cls, value, force=False)
	Returns identifier in quotes and proper-escaped for queries, if value needs quoting (has non-alphanumerics, starts with number, or is reserved). More...

Public Attributes
	CONVERTERS

	dsn
	Data Source Name, as URL like `"postgresql://user@host/dbname"`. More...

Static Public Attributes
dictionary	ADAPTERS = {}
	Registered adapters for Python->SQL, as {typeclass: converter}. More...

dictionary	CONVERTERS = {}
	Registered converters for SQL->Python pending application, as {typename: converter}. More...

	MUTEX = collections.defaultdict(threading.RLock)
	Mutexes for exclusive transactions, as {Database instance: lock}. More...

tuple	POOL_SIZE = (1, 4)
	Connection pool default size per Database. More...

dictionary	POOLS = {}
	Connection pools, as {Database: psycopg2.pool.ConnectionPool}. More...

	ROW_FACTORY = None
	Registered row factory. More...

Static Public Attributes inherited from dblite.api.Queryable
	ENGINE = None
	Underlying database engine, "sqlite" for SQLite3 and "postgres" for PostgreSQL. More...

Static Public Attributes inherited from dblite.engines.postgres.Queryable
string	ENGINE = "postgres"
	Name of underlying database engine. More...

tuple	OPS
	Recognized binary operators for makeSQL() More...

Properties
	closed = property
	Whether database connection is currently not open. More...

	cursor = property
	Database engine cursor object, or `None` if closed. More...

	row_factory = property
	The custom row factory, if any, as `function(cursor, row tuple)`. More...

Properties inherited from dblite.api.Database
	row_factory = property
	The custom row factory, if any, as `function(cursor, row tuple)`. More...

Properties inherited from dblite.api.Queryable
	closed = property
	Whether currently not open. More...

	cursor = property
	Database engine cursor object, or `None` if closed. More...

Detailed Description

Convenience wrapper around psycopg2.ConnectionPool and Cursor.

Queries directly on the Database object use autocommit mode.

Definition at line 361 of file postgres.py.

Constructor & Destructor Documentation

◆ init()

def dblite.engines.postgres.Database.__init__	(		self,
			opts,
		**	kwargs
	)

Creates a new Database instance for Postgres.

By default uses a pool of 1..4 connections.

Connection parameters can also be specified in OS environment, via standard Postgres environment variables like `PGUSER` and `PGPASSWORD`.

Parameters

opts	Postgres connection string, or options dictionary as `dict(dbname=.., user=.., password=.., host=.., port=.., ..)`
kwargs	additional arguments given to engine constructor, e.g. `minconn=1, maxconn=4`

Definition at line 394 of file postgres.py.

Member Function Documentation

◆ enter()

def dblite.engines.postgres.Database.__enter__ ( self )

Context manager entry, opens database if not already open, returns Database object.

Reimplemented from dblite.api.Database.

Definition at line 406 of file postgres.py.

◆ exit()

def dblite.engines.postgres.Database.__exit__	(	self,
		exc_type,
		exc_val,
		exc_trace
	)

Context manager exit, closes database and any pending transactions if open.

Reimplemented from dblite.api.Database.

Definition at line 412 of file postgres.py.

◆ close()

def dblite.engines.postgres.Database.close	(	self,
		commit = `None`
	)

Closes the database and any pending transactions, if open.

Parameters

commit `True` for explicit commit on open transactions, `False` for explicit rollback on open transactions, `None` defaults to `commit` flag from transaction creations

Reimplemented from dblite.api.Database.

Definition at line 471 of file postgres.py.

◆ execute()

def dblite.engines.postgres.Database.execute	(	self,
		sql,
		args = `()`
	)

Executes SQL statement, returns psycopg cursor.

Parameters

sql	SQL statement to execute, with psycopg-specific parameter bindings, if any
args	dictionary for %(name)s placeholders, or a sequence for positional s placeholders, or None

Reimplemented from dblite.api.Queryable.

Definition at line 426 of file postgres.py.

◆ executemany()

def dblite.engines.postgres.Database.executemany	(	self,
		sql,
		args
	)

Executes the SQL statement against all parameter sequences.

Parameters

sql	SQL statement to execute, with psycopg-specific parameter bindings
args	iterable of query parameters, as dictionaries for %(name)s placeholders or sequences for positional s placeholders

Reimplemented from dblite.api.Queryable.

Definition at line 438 of file postgres.py.

◆ executescript()

def dblite.engines.postgres.Database.executescript	(	self,
		sql
	)

Executes the SQL as script of any number of statements.

Reloads internal schema structure from database.

Parameters

sql	script with one or more SQL statements

Reimplemented from dblite.api.Queryable.

Definition at line 450 of file postgres.py.

◆ init_pool()

def dblite.engines.postgres.Database.init_pool	(		cls,
			db,
			minconn = `POOL_SIZE[0]`,
			maxconn = `POOL_SIZE[1]`,
		**	kwargs
	)

Initializes connection pool for Database if not already initialized.

Definition at line 583 of file postgres.py.

◆ make_cursor()

def dblite.engines.postgres.Database.make_cursor	(	self,
		commit = `False`,
		autocommit = `False`,
		schema = `None`,
		lazy = `False`,
		itersize = `None`
	)

Context manager for psycopg connection cursor.

Creates a new cursor on an unused connection and closes it when exiting context, committing changes if specified.

Parameters

commit	commit at the end on success
autocommit	connection autocommit mode
schema	name of Postgres schema to use, if not using default `"public"`
lazy	if true, returns a named server-side cursor that fetches rows iteratively in batches; only supports making a single query
itersize	batch size in rows for server-side cursor

Returns: psycopg2 Cursor

Definition at line 549 of file postgres.py.

◆ open()

def dblite.engines.postgres.Database.open ( self )

Opens database connection if not already open.

Reimplemented from dblite.api.Database.

Definition at line 456 of file postgres.py.

◆ transaction()

def dblite.engines.postgres.Database.transaction	(		self,
			commit = `True`,
			exclusive = `False`,
		**	kwargs
	)

Returns a transaction context manager.

Context is breakable by raising Rollback.

Parameters

commit	whether transaction commits at exiting with-block
exclusive	whether entering a with-block is exclusive over other Transaction instances on this Database
kwargs	engine-specific arguments, like `schema="other", lazy=True` for Postgres

Reimplemented from dblite.api.Database.

Definition at line 530 of file postgres.py.

Member Data Documentation

◆ ADAPTERS

dictionary dblite.engines.postgres.Database.ADAPTERS = {}

static

Registered adapters for Python->SQL, as {typeclass: converter}.

Definition at line 364 of file postgres.py.

◆ CONVERTERS [1/2]

dictionary dblite.engines.postgres.Database.CONVERTERS = {}

static

Registered converters for SQL->Python pending application, as {typename: converter}.

Definition at line 367 of file postgres.py.

◆ CONVERTERS [2/2]

dblite.engines.postgres.Database.CONVERTERS

Definition at line 599 of file postgres.py.

◆ dsn

dblite.engines.postgres.Database.dsn

Data Source Name, as URL like `"postgresql://user@host/dbname"`.

Definition at line 397 of file postgres.py.

◆ MUTEX

dblite.engines.postgres.Database.MUTEX = collections.defaultdict(threading.RLock)

static

Mutexes for exclusive transactions, as {Database instance: lock}.

Definition at line 370 of file postgres.py.

◆ POOL_SIZE

tuple dblite.engines.postgres.Database.POOL_SIZE = (1, 4)

static

Connection pool default size per Database.

Definition at line 373 of file postgres.py.

◆ POOLS

dictionary dblite.engines.postgres.Database.POOLS = {}

static

Connection pools, as {Database: psycopg2.pool.ConnectionPool}.

Definition at line 376 of file postgres.py.

◆ ROW_FACTORY

dblite.engines.postgres.Database.ROW_FACTORY = None

static

Registered row factory.

Definition at line 379 of file postgres.py.

Property Documentation

◆ closed

dblite.engines.postgres.Database.closed = property

static

Whether database connection is currently not open.

Definition at line 485 of file postgres.py.

◆ cursor

dblite.engines.postgres.Database.cursor = property

static

Database engine cursor object, or `None` if closed.

Definition at line 493 of file postgres.py.

◆ row_factory

dblite.engines.postgres.Database.row_factory = property

static

The custom row factory, if any, as `function(cursor, row tuple)`.

Definition at line 501 of file postgres.py.

The documentation for this class was generated from the following file:

dblite/engines/postgres.py

Public Member Functions

Public Attributes

Static Public Attributes

Properties

Detailed Description

Constructor & Destructor Documentation

◆ __init__()

Member Function Documentation

◆ __enter__()

◆ __exit__()

◆ close()

◆ execute()

◆ executemany()

◆ executescript()

◆ init_pool()

◆ make_cursor()

◆ open()

◆ transaction()

Member Data Documentation

◆ ADAPTERS

◆ CONVERTERS [1/2]

◆ CONVERTERS [2/2]

◆ dsn

◆ MUTEX

◆ POOL_SIZE

◆ POOLS

◆ ROW_FACTORY

Property Documentation

◆ closed

◆ cursor

◆ row_factory

◆ init()

◆ enter()

◆ exit()