Create a connection to a DBMS
Connect to a DBMS going through the appropriate authentication procedure.
Some implementations may allow you to have multiple connections open, so you
may invoke this function repeatedly assigning its output to different
objects.
The authentication mechanism is left unspecified, so check the
documentation of individual drivers for details.
Use dbCanConnect()
to check if a connection can be established.
dbConnect(drv, ...)
drv |
an object that inherits from DBIDriver, or an existing DBIConnection object (in order to clone an existing connection). |
... |
authentication arguments needed by the DBMS instance; these
typically include |
dbConnect()
returns an S4 object that inherits from DBIConnection.
This object is used to communicate with the database engine.
A format()
method is defined for the connection object.
It returns a string that consists of a single line of text.
DBI recommends using the following argument names for authentication
parameters, with NULL
default:
user
for the user name (default: current user)
password
for the password
host
for the host name (default: local connection)
port
for the port number (default: local connection)
dbname
for the name of the database on the host, or the database file
name
The defaults should provide reasonable behavior, in particular a
local connection for host = NULL
. For some DBMS (e.g., PostgreSQL),
this is different to a TCP/IP connection to localhost
.
In addition, DBI supports the bigint
argument that governs how
64-bit integer data is returned. The following values are supported:
"integer"
: always return as integer
, silently overflow
"numeric"
: always return as numeric
, silently round
"character"
: always return the decimal representation as character
"integer64"
: return as a data type that can be coerced using
as.integer()
(with warning on overflow), as.numeric()
and as.character()
dbDisconnect()
to disconnect from a database.
Other DBIDriver generics:
DBIDriver-class
,
dbCanConnect()
,
dbDataType()
,
dbDriver()
,
dbGetInfo()
,
dbIsReadOnly()
,
dbIsValid()
,
dbListConnections()
Other DBIConnector generics:
DBIConnector-class
,
dbDataType()
,
dbGetConnectArgs()
,
dbIsReadOnly()
# SQLite only needs a path to the database. (Here, ":memory:" is a special # path that creates an in-memory database.) Other database drivers # will require more details (like user, password, host, port, etc.) con <- dbConnect(RSQLite::SQLite(), ":memory:") con dbListTables(con) dbDisconnect(con) # Bad, for subtle reasons: # This code fails when RSQLite isn't loaded yet, # because dbConnect() doesn't know yet about RSQLite. dbListTables(con <- dbConnect(RSQLite::SQLite(), ":memory:"))
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