sqliteSupport: 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=10, fetch.default.rec = 500, force.reload=FALSE)
   sqliteDriverInfo(obj, what)
   sqliteDescribeDriver(obj, verbose = FALSE, ...)
   sqliteCloseDriver(drv, ...)
   ## SQLiteConnection-related
   sqliteNewConnection(drv, dbname, mode = 0)
   sqliteCloneConnection(drv, ...)
   sqliteConnectionInfo(obj, what)
   sqliteDescribeConnection(obj, verbose = FALSE, ...)
   sqliteCloseConnection(con, ..., force = FALSE)
   ## SQLiteResult-related
   sqliteExecStatement(con, statement)
   sqliteFetch(res, n=0, ...)
   sqliteQuickSQL(con, statement, ...)
   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, ...)
   sqliteWriteTable(con, name, value, field.types, row.names = TRUE, 
      overwrite=FALSE, append=FALSE, ...)
   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

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 and sqliteCloneConnection.

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).

mode

positive integer describing the mode for opening the database (SQLite's underlying API currently does not yet use it, but it is reserved for future functionality). The default is 0.

max.results

positive integer indicating the maximum number of results that SQLite connections will hold open. The current default of 1 is hardcoded in the C code.

force

logical indicating whether to close a connection that has open result sets. The default is FALSE.

statement

character string holding SQL statements.

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.

...

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.
sqliteCloneConnection 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. 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.