sqliteSupport {RSQLite}R Documentation

Support Functions

Description

These functions are the workhorses behind the RSQLite package, but users need not invoke these directly.

Usage

   ## SQLiteDriver-related
   sqliteInitDriver(max.con=16, fetch.default.rec = 500, force.reload=FALSE,
                    shared.cache=FALSE)
   sqliteDriverInfo(obj, what, ...)
   sqliteDescribeDriver(obj, verbose = FALSE, ...)
   sqliteCloseDriver(drv, ...)

   ## SQLiteConnection-related
   sqliteNewConnection(drv, dbname, loadable.extensions=FALSE, cache_size=NULL,
                       synchronous=0)
   sqliteConnectionInfo(obj, what, ...)
   sqliteDescribeConnection(obj, verbose = FALSE, ...)
   sqliteCloseConnection(con, ...)

   ## SQLiteResult-related
   sqliteExecStatement(con, statement, bind.data=NULL)
   sqliteTransactionStatement(con, statement)
   sqliteFetch(res, n=0, ...)
   sqliteQuickSQL(con, statement, bind.data=NULL, ...)
   sqliteResultInfo(obj, what, ...)
   sqliteDescribeResult(obj, verbose = FALSE, ...)
   sqliteCloseResult(res, ...)

   ## data mappings and convenience functions
   sqliteDataType(obj, ...)
   sqliteReadTable(con, name, row.names = "row_names", check.names = TRUE, ...)
   sqliteImportFile(con, name, value, field.types, overwrite=FALSE,
      append=FALSE, header, row.names, nrows=50, sep=",", eol="\n",
      skip = 0, ...)
   sqliteWriteTable(con, name, value, row.names = TRUE,
                    overwrite = FALSE, append = FALSE,
                    field.types = NULL, ...)
   sqliteTableFields(con, name, ...)

Arguments

max.con positive integer specifying maximum number of open connections. The default is 10. Note that since SQLite is embedded in R/S-Plus connections are simple, very efficient direct C calls.
fetch.default.rec default number of rows to fetch (move to R/S-Plus). This default is used in sqliteFetch. The default is 500.
force.reload logical indicating whether to re-initialize the driver. This may be useful if you want to change the defaults (e.g., fetch.default.rec). Note that the driver is a singleton (subsequent inits just returned the previously initialized driver, thus this argument).
obj any of the SQLite DBI objects (e.g., SQLiteConnection, SQLiteResult).
what character vector of metadata to extract, e.g., "version", "statement", "isSelect".
verbose logical controlling how much information to display. Defaults to FALSE.
drv an SQLiteDriver object as produced by sqliteInit.
con an SQLiteConnection object as produced by sqliteNewConnection.
res an SQLiteResult object as produced by by sqliteExecStatement.
dbname character string with the SQLite database file name (SQLite, like Microsoft's Access, stores an entire database in one file).
loadable.extensions logical describing whether loadable extensions will be enabled for this connection. The default is FALSE.
shared.cache logical describing whether shared-cache mode should be enabled on the SQLite driver. The default is FALSE.
bind.data a data frame which will be used to bind variables in the statement.
cache_size positive integer to pass to the PRAGMA cache_size; this changes the maximum number of disk pages that SQLite will hold in memory (SQLite's default is 2000 pages).
synchronous values the PRAGMA synchronous flag, possible values are 0, 1, or 2 or the corresponding strings "OFF", "NORMAL", or "FULL". The RSQLite package uses a default of 0 (OFF), although SQLite's default is 2 (FULL) as of version 3.2.8. Users have reported significant speed ups using sychronous="OFF", and the SQLite documentation itself implies considerably improved performance at the very modest risk of database corruption in the unlikely case of the operating system (not the R application) crashing.
force logical indicating whether to close a connection that has open result sets. The default is FALSE.
statement character string holding SQL statements.
n number of rows to fetch from the given result set. A value of -1 indicates to retrieve all the rows. The default of 0 specifies to extract whatever the fetch.default.rec was specified during driver initialization sqliteInit.
name character vector of names (table names, fields, keywords).
value a data.frame.
field.types a list specifying the mapping from R/S-Plus fields in the data.frame value to SQL data types. The default is sapply(value,SQLDataType), see SQLiteSQLType.
row.names a logical specifying whether to prepend the value data.frame row names or not. The default is TRUE.
check.names a logical specifying whether to convert DBMS field names into legal S names. Default is TRUE.
overwrite logical indicating whether to replace the table name with the contents of the data.frame value. The defauls is FALSE.
append logical indicating whether to append value to the existing table name.
header logical, does the input file have a header line? Default is the same heuristic used by read.table, i.e., TRUE if the first line has one fewer column that the second line.
nrows number of lines to rows to import using read.table from the input file to create the proper table definition. Default is 50.
sep field separator character.
eol end-of-line separator.
skip number of lines to skip before reading data in the input file.
... placeholder for future use.

Value

sqliteInitDriver returns an SQLiteDriver object.
sqliteDriverInfo returns a list of name-value metadata pairs.
sqliteDescribeDriver returns NULL (displays the object's metadata).
sqliteCloseDriver returns a logical indicating whether the operation succeeded or not.
sqliteNewConnection returns an SQLiteConnection object.
sqliteConnectionInforeturns a list of name-value metadata pairs.
sqliteDescribeConnection returns NULL (displays the object's metadata).
sqliteCloseConnection returns a logical indicating whether the operation succeeded or not.
sqliteExecStatement returns an SQLiteResult object.
sqliteFetch returns a data.frame.
sqliteQuickSQL returns either a data.frame if the statement is a select-like or NULL otherwise.
sqliteDescribeResult returns NULL (displays the object's metadata).
sqliteCloseResult returns a logical indicating whether the operation succeeded or not.
sqliteReadTable returns a data.frame with the contents of the DBMS table.
sqliteWriteTable returns a logical indicating whether the operation succeeded or not.
sqliteImportFile returns a logical indicating whether the operation succeeded or not.
sqliteTableFields returns a character vector with the table name field names.
sqliteDataType retuns a character string with the closest SQL data type. Note that SQLite is typeless, so this is mostly for creating table that are compatible across RDBMS.
sqliteResultInfo returns a list of name-value metadata pairs.

Constants

.SQLitePkgName (currently "RSQLite"), .SQLitePkgVersion (the R package version), .SQLitePkgRCS (the RCS revision), .SQLitecle.NA.string (character that SQLite uses to denote NULL on input), .conflicts.OK.


[Package RSQLite version 0.6-9 Index]