R: Create a connection object to an PostgreSQL DBMS

dbConnect-methods {RPostgreSQL}

R Documentation

Create a connection object to an PostgreSQL DBMS

Description

These methods are straight-forward implementations of the corresponding generic functions.

Methods

drv: an object of class PostgreSQLDriver, or the character string "PostgreSQL" or an PostgreSQLConnection.
conn: an PostgreSQLConnection object as produced by dbConnect.
host: Name or the numeric IPaddress of the host to connect to. If address is specified, it should be in the standard IPv4 address format, e.g., 172.28.40.9 or if your machine supports IPv6, you can also use those addresses. The default is to connect to localhost by a UNIX domain socket.
dbname: The database name. Defaults to "", which is interpreted as PostgreSQL default. Most parameters are currently passed to PQsetdbLogin() as is. If dbname contains an = sign or has a valid connection URI prefix, it is taken as a conninfo for PQconnectdb() depending on the linked driver version. Refer to https://www.postgresql.org/docs/current/libpq-connect.html for detail.
user: PostgreSQL user name to connect as. Defaults to be the same as the operating system name of the user running the application.
password: Password to be used if the server demands password authentication.
port: Port number to connect to at the server host.
tty: Ignored (formerly, this specified where to send server debug output).
options: Command-line options to be sent to the server.
forceISOdate: logical if the communication of date (time stamp) from PostgreSQL is forced to ISO style at conection. This is an exception that is not really set by an option for PQsetdbLogin, but by issueing dbGetQuery(con, "set datestyle to ISO") after connection.

Side Effects

A connection between R/S-Plus and an PostgreSQL server is established. The current implementation supports up to 100 simultaneous connections.

References

See the Database Interface definition document DBI.pdf in the base directory of this package or https://cran.r-project.org/package=DBI.

Examples

## Not run: 
# create an PostgreSQL instance and create one connection.
drv <- dbDriver("PostgreSQL")

# open the connection using user, passsword, etc., as
con <- dbConnect(drv, dbname = "postgres")

df <- dbGetQuery(con, statement = paste(
                      "SELECT itemCode, itemCost, itemProfit",
                      "FROM sales",
                      "SORT BY itemName"));
# Run an SQL statement by creating first a resultSet object
rs <- dbSendQuery(con, statement = paste(
                      "SELECT itemCode, itemCost, itemProfit",
                      "FROM sales",
                      "SORT BY itemName"));

# we now fetch records from the resultSet into a data.frame
df <- fetch(rs, n = -1)   # extract all rows
dim(df)

## End(Not run)