Transaction context manager, provides convenience methods for queries. More...

Inheritance diagram for dblite.engines.postgres.Transaction:

Public Member Functions
def	__init__ (self, db, commit=True, exclusive=False, schema=None, lazy=False, itersize=None, **__)
	Creates a transaction context manager. More...

def	__enter__ (self)
	Context manager entry, opens cursor, returns Transaction object. More...

def	__exit__ (self, exc_type, exc_val, exc_trace)
	Context manager exit, closes cursor, commits or rolls back as specified on creation. More...

def	close (self, commit=None)
	Closes the transaction, performing commit or rollback as specified, and releases database connection back to connection pool. More...

def	commit (self)
	Commits pending actions, if any. 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	rollback (self)
	Rolls back pending actions, if any. More...

Public Member Functions inherited from dblite.api.Transaction
def	__init__ (self, db, commit=True, exclusive=False, **kwargs)
	Constructs a new transaction. More...

def	__del__ (self)
	Closes the transaction, 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...

Properties
	closed = property
	Whether transaction is currently not open. More...

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

	database = property
	Returns transaction Database instance. More...

Properties inherited from dblite.api.Transaction
	database = property
	Returns transaction Database instance. 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...

Additional Inherited Members
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...

Detailed Description

Transaction context manager, provides convenience methods for queries.

Supports server-side cursors; those can only be used for making a single query.

Must be closed explicitly if not used as context manager in a with-block. Block can be exited early by raising Rollback.

Definition at line 634 of file postgres.py.

Constructor & Destructor Documentation

◆ init()

def dblite.engines.postgres.Transaction.__init__	(		self,
			db,
			commit = `True`,
			exclusive = `False`,
			schema = `None`,
			lazy = `False`,
			itersize = `None`,
		**	__
	)

Creates a transaction context manager.

Context is breakable by raising Rollback.

Parameters

db	Database instance
commit	whether transaction commits automatically at exiting with-block
exclusive	whether entering a with-block is exclusive over other Transaction instances Database
schema	search_path to use in this transaction
lazy	if true, uses a server-side cursor to fetch results from server iteratively in batches instead of all at once, supports one single query only
itersize	batch size for server-side cursor (defaults to 2000 rows)

Definition at line 651 of file postgres.py.

Member Function Documentation

◆ enter()

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

Context manager entry, opens cursor, returns Transaction object.

Reimplemented from dblite.api.Transaction.

Definition at line 662 of file postgres.py.

◆ exit()

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

Context manager exit, closes cursor, commits or rolls back as specified on creation.

Reimplemented from dblite.api.Transaction.

Definition at line 675 of file postgres.py.

◆ close()

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

Closes the transaction, performing commit or rollback as specified, and releases database connection back to connection pool.

Required if not using transaction as context manager in a with-block.

Parameters

commit `True` for explicit commit, `False` for explicit rollback, `None` defaults to `commit` flag from creation

Reimplemented from dblite.api.Transaction.

Definition at line 698 of file postgres.py.

◆ commit()

def dblite.engines.postgres.Transaction.commit ( self )

Commits pending actions, if any.

Reimplemented from dblite.api.Transaction.

Definition at line 745 of file postgres.py.

◆ execute()

def dblite.engines.postgres.Transaction.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 716 of file postgres.py.

◆ executemany()

def dblite.engines.postgres.Transaction.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 728 of file postgres.py.

◆ executescript()

def dblite.engines.postgres.Transaction.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 740 of file postgres.py.

◆ rollback()

def dblite.engines.postgres.Transaction.rollback ( self )

Rolls back pending actions, if any.

Reimplemented from dblite.api.Transaction.

Definition at line 749 of file postgres.py.

Property Documentation

◆ closed

dblite.engines.postgres.Transaction.closed = property

static

Whether transaction is currently not open.

Definition at line 755 of file postgres.py.

◆ cursor

dblite.engines.postgres.Transaction.cursor = property

static

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

Definition at line 762 of file postgres.py.

◆ database

dblite.engines.postgres.Transaction.database = property

static

Returns transaction Database instance.

Definition at line 771 of file postgres.py.

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

dblite/engines/postgres.py

Public Member Functions

Properties

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ __init__()

Member Function Documentation

◆ __enter__()

◆ __exit__()

◆ close()

◆ commit()

◆ execute()

◆ executemany()

◆ executescript()

◆ rollback()

Property Documentation

◆ closed

◆ cursor

◆ database

◆ init()

◆ enter()

◆ exit()