def copy_from(self, file, table, sep='\t', null='\\N', size=8192,
columns=None):
"""Reads data from a file-like object appending them to a database
table (COPY table FROM file syntax).
The source file must have both read() and readline() method.
TODO: Improve error handling
"""
if columns:
columns_str = '(%s)' % ','.join([column for column in columns])
else:
columns_str = ''
query = util.unicode_to_bytes(
"COPY %s%s FROM stdin WITH DELIMITER AS " % (
table, columns_str)) + \
util.quote_string(self._conn, sep) + b' NULL AS ' + \
util.quote_string(self._conn, null)
self._copysize = size
self._copyfile = file
try:
self._pq_execute(query)
finally:
self._copyfile = None
self._copysize = None
def copy_to(self, file, table, sep='\t', null='\\N', columns=None):
"""Writes the content of a table to a file-like object (COPY table
TO file syntax).
The target file must have a write() method.
TODO: Improve error handling
"""
if columns:
columns_str = '(%s)' % ','.join([column for column in columns])
else:
columns_str = ''
query = util.unicode_to_bytes(
"COPY %s%s TO stdout WITH DELIMITER AS " % (
table, columns_str)) + \
util.quote_string(self._conn, sep) + b' NULL AS ' + \
util.quote_string(self._conn, null)
self._copyfile = file
try:
self._pq_execute(query)
finally:
self._copyfile = None
def execute(self, query, parameters=None):
"""Prepare and execute a database operation (query or command).
Parameters may be provided as sequence or mapping and will be bound to
variables in the operation. Variables are specified in a
database-specific notation (see the module's paramstyle attribute for
details).
A reference to the operation will be retained by the cursor. If the
same operation object is passed in again, then the cursor can optimize
its behavior. This is most effective for algorithms where the same
operation is used, but different parameters are bound to it
(many times).
For maximum efficiency when reusing an operation, it is best to use
the .setinputsizes() method to specify the parameter types and sizes
ahead of time. It is legal for a parameter to not match the
predefined information; the implementation should compensate,
possibly with a loss of efficiency.
The parameters may also be specified as list of tuples to e.g. insert
multiple rows in a single operation, but this kind of usage is
deprecated: .executemany() should be used instead.
Return values are not defined.
"""
self._description = None
conn = self._conn
if self._name:
if self._query:
raise ProgrammingError(
"can't call .execute() on named cursors more than once")
if self._conn.autocommit:
raise ProgrammingError(
"can't use a named cursor outside of transactions")
if isinstance(query, six.text_type):
query = query.encode(self._conn._py_enc)
if parameters is not None:
self._query = _combine_cmd_params(query, parameters, conn)
else:
self._query = query
scroll = ""
if self._scrollable is not None:
scroll = self._scrollable and "SCROLL " or "NO SCROLL "
conn._begin_transaction()
self._clear_pgres()
if self._name:
self._query = \
util.unicode_to_bytes(
'DECLARE "%s" %sCURSOR %s HOLD FOR ' % (
self._name, scroll,
"WITH" if self._withhold else "WITHOUT")) \
+ self._query
self._pq_execute(self._query, conn._async)
