Other top-level objects - psycopg 3.1.9 documentation
Psycopg - PostgreSQL database adapter for Python - Psycopg documentation
Other top-level objects #
Connection information #
- class psycopg. ConnectionInfo ( pgconn ) #
Allow access to information about the connection.
The object is usually returned by
- dsn #
Return the connection string to connect to the database.
The string contains all the parameters set to a non-default value, which might come either from the connection string and parameters passed to
connect()or from environment variables. The password is never returned (you can read it using the
get_parameters()method returns the same information as a dict.
- status #
The status of the connection. See
The status can be one of a number of values. However, only two of these are seen outside of an asynchronous connection procedure:
BAD. A good connection to the database has the status
OK. Ordinarily, an
OKstatus will remain so until
Connection.close(), but a communications failure might result in the status changing to
- transaction_status #
The current in-transaction status of the session. See
The status can be
ACTIVE(a command is in progress),
INTRANS(idle, in a valid transaction block), or
INERROR(idle, in a failed transaction block).
UNKNOWNis reported if the connection is bad.
ACTIVEis reported only when a query has been sent to the server and not yet completed.
- backend_pid #
The process ID (PID) of the backend process handling this connection. See
- vendor #
A string representing the database vendor connected to.
Normally it is
PostgreSQL; it may be different if connected to a different database.
New in version 3.1.
- server_version #
An integer representing the server version. See
The number is formed by converting the major, minor, and revision numbers into two-decimal-digit numbers and appending them together. Starting from PostgreSQL 10 the minor version was dropped, so the second group of digits is always 00. For example, version 9.3.5 is returned as 90305, version 10.2 as 100002.
- error_message #
The error message most recently generated by an operation on the connection. See
- get_parameters ( ) #
Return the connection parameters values.
Return all the parameters set to a non-default value, which might come either from the connection string and parameters passed to ~Connection.connect() or from environment variables. The password is never returned (you can read it using the password attribute).
The dsn attribute returns the same information in the form as a string.
- timezone #
The Python timezone info of the connection’s timezone.
>>> conn.info.timezone zoneinfo.ZoneInfo(key='Europe/Rome')
- host #
The server host name of the active connection. See
This can be a host name, an IP address, or a directory path if the connection is via Unix socket. (The path case can be distinguished because it will always be an absolute path, beginning with
- hostaddr #
The server IP address of the connection. See
Only available if the libpq used is at least from PostgreSQL 12. Raise ~psycopg.NotSupportedError otherwise.
- parameter_status ( param_name ) #
Return a parameter setting of the connection.
Return None is the parameter is unknown.
Example of parameters are
PQparameterStatus()for all the available parameters.
- encoding #
The Python codec name of the connection’s client encoding.
The value returned is always normalized to the Python codec ~codecs.CodecInfo.name :
conn.execute("SET client_encoding TO LATIN9") conn.info.encoding 'iso8859-15'
A few PostgreSQL encodings are not available in Python and cannot be selected (currently
MULE_INTERNAL). The PostgreSQL
SQL_ASCIIencoding has the special meaning of "no encoding": see Strings adaptation for details.
The description Column object #
- class psycopg. Column ( cursor , index ) #
An object describing a column of data from a database result, as described by the DBAPI , so it can also be unpacked as a 7-items tuple.
The object is returned by Cursor.description .
- name #
The name of the column.
- type_code #
The numeric OID of the column.
- display_size #
The field size, for
varchar(n), None otherwise.
- internal_size #
The internal field size for fixed-size types, None otherwise.
- precision #
The number of digits for fixed precision types.
- scale #
The number of digits after the decimal point if available.
- class psycopg. Notify #
An asynchronous notification received from the database.
The object is usually returned by Connection.notifies() .