odbcConnect {RODBC}R Documentation

ODBC Open Connections

Description

Open connections to ODBC databases.

Usage

odbcConnect(dsn, uid = "", pwd = "", ...)

odbcDriverConnect(connection = "", case, believeNRows = TRUE,
                  colQuote, tabQuote = colQuote)

odbcReConnect(channel, case, believeNRows)

Arguments

dsn character string. A registered data source name.
uid, pwd UID and password for authentication (if required).
connection character string. See your ODBC documentation for the format.
... further arguments to be passed to odbcDriverConnect.
case Controls case changes for different DBMS engines. See Details.
channel RODBC connection object returned by odbcConnect.
believeNRows logical. Is the number of rows returned by the ODBC connection believable? Not true for Oracle and Sybase, apparently.
colQuote, tabQuote how to quote column (table) names in SQL statements. Can be of length 0 (no quoting), a length-1 character vector giving the quote character for both ends, or a length-2 character string giving the beginning and ending quotes. ANSI SQL uses doublequotes, but the default mode for a MySQL server is to use backticks.
The defaults are backtick (`) if the DBMS is identified as "MySQL" by the driver, and doublequote otherwise.

Details

odbcConnect establishes a connection to the dsn, and odbcDriverConnect allows a more flexible specification via a connection string. odbcConnect uses the connection string
"DSN=dsn;UID=uid;PWD=pwd", omitting the last two comments if they are empty. See the examples for other uses of connection strings.

For databases that translate table and column names the case must be set as appropriate. Allowable values are "nochange", "toupper" and "tolower" as well as the names of databases where the behaviour is known to us (currently "mysql" (which maps to lower case on Windows but not on Linux), "postgresql" (lower), "oracle" (upper) and "msaccess" (nochange)). If case is not specified, the default is "nochange" unless the appropriate value can be figured out from the DBMS name reported by the ODBC driver.

Function odbcReConnect re-connects to a database using the settings of an existing (and presumably now closed) channel object. Arguments case and believeNRows are taken from the object, but can be overridden by supplying those arguments.

Value

A non-negative integer which is used as handle if no error occurred, -1 otherwise. A successful return has class "RODBC", and attribute "connection.string" giving the full ODBC connection string.

Author(s)

Michael Lapsley, Brian Ripley

See Also

odbcClose, sqlQuery, odbcGetInfo

Examples

## Not run: 
# MySQL
channel <- odbcConnect("test", uid="ripley", pwd="secret")
# PostgreSQL
channel <- odbcConnect("pg", uid="ripley", pwd="secret", case="postgresql")

# re-connection
odbcCloseAll()
channel <- odbcReConnect(channel) # must re-assign as the data may well change
## End(Not run)

[Package RODBC version 1.1-9 Index]