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"""
Creates a new Greenplum database connection.
"""
import getml.communication as comm
import getml.constants as constants
from .connection import Connection
[docs]def connect_greenplum(
dbname,
user,
password,
host,
hostaddr,
port=5432,
time_formats=None,
conn_id="default",
):
"""Creates a new Greenplum database connection.
But first, make sure your database is running and you can reach it
from via your command line.
Args:
dbname (str):
The name of the database to which you want to connect.
user (str):
User name with which to log into the Greenplum database.
password (str):
Password with which to log into the Greenplum database.
host (str):
Host of the Greenplum database.
hostaddr (str):
IP address of the Greenplum database.
port(int, optional):
Port of the Greenplum database.
The default port used by Greenplum is 5432.
If you do not know, which port to use, type the following into your
Greenplum client:
.. code-block:: sql
SELECT setting FROM pg_settings WHERE name = 'port';
time_formats (List[str], optional):
The list of formats tried when parsing time stamps.
The formats are allowed to contain the following
special characters:
* %w - abbreviated weekday (Mon, Tue, ...)
* %W - full weekday (Monday, Tuesday, ...)
* %b - abbreviated month (Jan, Feb, ...)
* %B - full month (January, February, ...)
* %d - zero-padded day of month (01 .. 31)
* %e - day of month (1 .. 31)
* %f - space-padded day of month ( 1 .. 31)
* %m - zero-padded month (01 .. 12)
* %n - month (1 .. 12)
* %o - space-padded month ( 1 .. 12)
* %y - year without century (70)
* %Y - year with century (1970)
* %H - hour (00 .. 23)
* %h - hour (00 .. 12)
* %a - am/pm
* %A - AM/PM
* %M - minute (00 .. 59)
* %S - second (00 .. 59)
* %s - seconds and microseconds (equivalent to %S.%F)
* %i - millisecond (000 .. 999)
* %c - centisecond (0 .. 9)
* %F - fractional seconds/microseconds (000000 - 999999)
* %z - time zone differential in ISO 8601 format (Z or +NN.NN)
* %Z - time zone differential in RFC format (GMT or +NNNN)
* %% - percent sign
conn_id (str, optional):
The name to be used to reference the connection.
If you do not pass anything, this will create a new default connection.
Note:
By selecting an existing table of your database in
:func:`~getml.DataFrame.from_db` function, you can create
a new :class:`~getml.DataFrame` containing all its data.
Alternatively you can use the
:meth:`~.getml.DataFrame.read_db` and
:meth:`~.getml.DataFrame.read_query` methods to replace
the content of the current :class:`~getml.DataFrame`
instance or append further rows based on either a table or a
specific query.
You can also write your results back into the Greenplum
database. By passing the name for the destination table to
:meth:`getml.Pipeline.transform`, the features
generated from your raw data will be written back. Passing
them into :meth:`getml.Pipeline.predict`, instead,
makes predictions of the target variables to new, unseen data
and stores the result into the corresponding table.
"""
# -------------------------------------------
time_formats = time_formats or constants.TIME_FORMATS
# -------------------------------------------
# Prepare command.
cmd = dict()
cmd["name_"] = ""
cmd["type_"] = "Database.new"
cmd["db_"] = "greenplum"
cmd["host_"] = host
cmd["hostaddr_"] = hostaddr
cmd["port_"] = port
cmd["dbname_"] = dbname
cmd["user_"] = user
cmd["time_formats_"] = time_formats
cmd["conn_id_"] = conn_id
# -------------------------------------------
# Send JSON command to engine.
sock = comm.send_and_get_socket(cmd)
# -------------------------------------------
# The password is sent separately, so it doesn't
# end up in the logs.
comm.send_string(sock, password)
# -------------------------------------------
# Make sure that everything went well.
msg = comm.recv_string(sock)
if msg != "Success!":
comm.engine_exception_handler(msg)
# -------------------------------------------
return Connection(conn_id=conn_id)