SQLite {RSQLite} | R Documentation |
This function initializes the SQLite engine. It returns an object that allows you to connect to the SQLite engine embedded in R.
SQLite(max.con = 200, fetch.default.rec = 500, force.reload = FALSE, shared.cache=FALSE)
max.con |
IGNORED. As of RSQLite 0.9.0, connections are managed dynamically and there is no predefined limit to the number of connections you can have in a given R session. |
fetch.default.rec |
default number of records to fetch at one time from the database.
The |
force.reload |
should the package code be reloaded (reinitialized)?
Setting this to |
shared.cache |
logical describing whether shared-cache mode should be enabled on the SQLite
driver. The default is |
This object is a singleton, that is, on subsequent invocations it returns the same initialized object.
This implementation allows the R embedded SQLite engine to work with multiple database instances through multiple connections simultaneously.
SQLite keeps each database instance in one single file. The name of the database is the file name, thus database names should be legal file names in the running platform.
An object of class SQLiteDriver
which extends
dbDriver
and dbObjectId
.
This object is needed to create connections
to the embedded SQLite database.
There can be many SQLite database instances running
simultaneously.
The R client part of the database communication is initialized,
but note that connecting to database instances needs to be done through
calls to dbConnect
.
SQLite is a single-user database engine, so no authentication is required.
See the Omega Project for Statistical Computing http://stat.bell-labs.com/RS-DBI for more details on the R database interface.
See the Adobe PDF file DBI.pdf
under the doc
subdirectory of the DBI package, i.e.,
system.file("doc", "DBI.pdf", package = "DBI")
See the documentation at the SQLite Web site http://www.sqlite.org for details.
David A. James
On database drivers:
dbDriver
,
dbUnloadDriver
,
dbListConnections
.
On connections, SQL statements and resultSets:
dbConnect
,
dbDisconnect
,
dbSendQuery
,
dbGetQuery
,
fetch
,
dbListResults
.
On transaction management:
On meta-data:
summary
,
dbGetInfo
,
dbListTables
,
dbListFields
,
dbColumnInfo
,
dbGetException
,
dbGetStatement
,
dbHasCompleted
,
dbGetRowCount
,
dbGetRowsAffected
.
# create a SQLite instance and create one connection. m <- dbDriver("SQLite") # initialize a new database to a tempfile and copy some data.frame # from the base package into it tfile <- tempfile() con <- dbConnect(m, dbname = tfile) data(USArrests) dbWriteTable(con, "USArrests", USArrests) # query rs <- dbSendQuery(con, "select * from USArrests") d1 <- fetch(rs, n = 10) # extract data in chunks of 10 rows dbHasCompleted(rs) d2 <- fetch(rs, n = -1) # extract all remaining data dbHasCompleted(rs) dbClearResult(rs) dbListTables(con) # clean up dbDisconnect(con) file.info(tfile) file.remove(tfile)