Together, SQLite() and dbConnect() allow you to connect to a SQLite database file. See DBI::dbSendQuery() for how to issue queries and receive results.

SQLite(...)

# S4 method for SQLiteDriver
dbConnect(drv, dbname = "", ...,
  loadable.extensions = TRUE, default.extensions = loadable.extensions,
  cache_size = NULL, synchronous = "off", flags = SQLITE_RWC,
  vfs = NULL, bigint = c("integer64", "integer", "numeric", "character"))

# S4 method for SQLiteConnection
dbConnect(drv, ...)

# S4 method for SQLiteConnection
dbDisconnect(conn, ...)

Arguments

...

In previous versions, SQLite() took arguments. These have now all been moved to dbConnect(), and any arguments here will be ignored with a warning.

drv, conn

An objected generated by SQLite(), or an existing SQLiteConnection. If an connection, the connection will be cloned.

dbname

The path to the database file. 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. There are two exceptions:

  • "" will create a temporary on-disk database. The file will be deleted when the connection is closed.

  • ":memory:" or "file::memory:" will create a temporary in-memory database.

loadable.extensions

When TRUE (default) SQLite3 loadable extensions are enabled. Setting this value to FALSE prevents extensions from being loaded.

default.extensions

When TRUE (default) the initExtension() function will be called on the new connection.Setting this value to FALSE requires calling initExtension() manually.

cache_size

Advanced option. A positive integer to change the maximum number of disk pages that SQLite holds in memory (SQLite's default is 2000 pages). See http://www.sqlite.org/pragma.html#pragma_cache_size for details.

synchronous

Advanced options. Possible values for synchronous are "off" (the default), "normal", or "full". Users have reported significant speed ups using sychronous = "off", and the SQLite documentation itself implies considerable improved performance at the very modest risk of database corruption in the unlikely case of the operating system (not the R application) crashing. See http://www.sqlite.org/pragma.html#pragma_synchronous for details.

flags

SQLITE_RWC: open the database in read/write mode and create the database file if it does not already exist; SQLITE_RW: open the database in read/write mode. Raise an error if the file does not already exist; SQLITE_RO: open the database in read only mode. Raise an error if the file does not already exist

vfs

Select the SQLite3 OS interface. See http://www.sqlite.org/vfs.html for details. Allowed values are "unix-posix", "unix-unix-afp", "unix-unix-flock", "unix-dotfile", and "unix-none".

bigint

The R type that 64-bit integer types should be mapped to, default is bit64::integer64, which allows the full range of 64 bit integers.

Value

SQLite() returns an object of class SQLiteDriver.

dbConnect() returns an object of class SQLiteConnection.

Details

Connections are automatically cleaned-up after they're deleted and reclaimed by the GC. You can use DBI::dbDisconnect() to terminate the connection early, but it will not actually close until all open result sets have been closed (and you'll get a warning message to this effect).

See also

The corresponding generic functions DBI::dbConnect() and DBI::dbDisconnect().

Examples

library(DBI) # Initialize a temporary in memory database and copy a data.frame into it con <- dbConnect(RSQLite::SQLite(), ":memory:") data(USArrests) dbWriteTable(con, "USArrests", USArrests) dbListTables(con)
#> [1] "USArrests"
# Fetch all query results into a data frame: dbGetQuery(con, "SELECT * FROM USArrests")
#> Murder Assault UrbanPop Rape #> 1 13.2 236 58 21.2 #> 2 10.0 263 48 44.5 #> 3 8.1 294 80 31.0 #> 4 8.8 190 50 19.5 #> 5 9.0 276 91 40.6 #> 6 7.9 204 78 38.7 #> 7 3.3 110 77 11.1 #> 8 5.9 238 72 15.8 #> 9 15.4 335 80 31.9 #> 10 17.4 211 60 25.8 #> 11 5.3 46 83 20.2 #> 12 2.6 120 54 14.2 #> 13 10.4 249 83 24.0 #> 14 7.2 113 65 21.0 #> 15 2.2 56 57 11.3 #> 16 6.0 115 66 18.0 #> 17 9.7 109 52 16.3 #> 18 15.4 249 66 22.2 #> 19 2.1 83 51 7.8 #> 20 11.3 300 67 27.8 #> 21 4.4 149 85 16.3 #> 22 12.1 255 74 35.1 #> 23 2.7 72 66 14.9 #> 24 16.1 259 44 17.1 #> 25 9.0 178 70 28.2 #> 26 6.0 109 53 16.4 #> 27 4.3 102 62 16.5 #> 28 12.2 252 81 46.0 #> 29 2.1 57 56 9.5 #> 30 7.4 159 89 18.8 #> 31 11.4 285 70 32.1 #> 32 11.1 254 86 26.1 #> 33 13.0 337 45 16.1 #> 34 0.8 45 44 7.3 #> 35 7.3 120 75 21.4 #> 36 6.6 151 68 20.0 #> 37 4.9 159 67 29.3 #> 38 6.3 106 72 14.9 #> 39 3.4 174 87 8.3 #> 40 14.4 279 48 22.5 #> 41 3.8 86 45 12.8 #> 42 13.2 188 59 26.9 #> 43 12.7 201 80 25.5 #> 44 3.2 120 80 22.9 #> 45 2.2 48 32 11.2 #> 46 8.5 156 63 20.7 #> 47 4.0 145 73 26.2 #> 48 5.7 81 39 9.3 #> 49 2.6 53 66 10.8 #> 50 6.8 161 60 15.6
# Or do it in batches rs <- dbSendQuery(con, "SELECT * FROM USArrests") d1 <- dbFetch(rs, n = 10) # extract data in chunks of 10 rows dbHasCompleted(rs)
#> [1] FALSE
d2 <- dbFetch(rs, n = -1) # extract all remaining data dbHasCompleted(rs)
#> [1] TRUE
dbClearResult(rs) # clean up dbDisconnect(con)