dbConnect {DBI} | R Documentation |
Connect to a DBMS going through the appropriate authorization procedure.
dbConnect(drv, ...) dbDisconnect(conn, ...)
drv |
an object that inherits from DBIDriver ,
a character string specifying the DBMS driver, e.g., "RPgSQL",
"ROracle", "Informix", or possibly another dbConnect object.
|
conn |
a connection object as produced by dbConnect .
|
... |
authorization arguments needed by the DBMS instance; these
typically include user , password , dbname ,
host , port , etc. For details see the appropriate
DBIDriver .
|
Some implementations may allow you to have multiple connections open, so you may invoke this function repeatedly assigning its output to different objects.
The authorization mechanism is left unspecified, so check the documentation of individual drivers for details.
An object that extends DBIConnection
in a database-specific
manner. For instance dbConnect("MySQL")
produces an object
of class MySQLConnection
.
This object is used to direct commands to the database engine.
dbDisconnect
returns a logical value indicating whether
the operation succeeded or not.
A connection between R/Splus and the database server is established, and the R/Splus program becomes a client of the database engine. Typically the connections is through the TCP/IP protocol, but this will depend on vendor-specific details.
Make sure you close the connection using dbDisconnect(conn)
when it is not longer needed.
See the Database Interface definition document
DBI.pdf
in the base directory of this package
or http://developer.r-project.org/db.
dbConnect
dbSendQuery
dbGetQuery
fetch
dbCommit
dbGetInfo
dbReadTable
## Not run: # create an RODBC instance and create one connection. m <- dbDriver("RODBC") # open the connection using user, passsword, etc., as # specified in the file \file{\$HOME/.my.cnf} con <- dbConnect(m, dsn="data.source", uid="user", pwd="password")) # Run an SQL statement by creating first a resultSet object rs <- dbSendQuery(con, statement = paste( "SELECT w.laser_id, w.wavelength, p.cut_off", "FROM WL w, PURGE P", "WHERE w.laser_id = p.laser_id", "SORT BY w.laser_id") # we now fetch records from the resultSet into a data.frame data <- fetch(rs, n = -1) # extract all rows dim(data) ## End(Not run)