DBI (version 0.5-1)

dbDataType: Determine the SQL data type of an object

Description

This is a generic function. The default method determines the SQL type of an R object according to the SQL 92 specification, which may serve as a starting point for driver implementations. The default method also provides a method for data.frame which will return a character vector giving the type for each column in the dataframe.

Usage

dbDataType(dbObj, obj, ...)

Arguments

dbObj

A object inheriting from DBIDriver or DBIConnection

obj

An R object whose SQL type we want to determine.

...

Other arguments passed on to methods.

Value

A character string specifying the SQL data type for obj.

Details

The data types supported by databases are different than the data types in R, but the mapping between the primitve types is straightforward: Any of the many fixed and varying length character types are mapped to character vectors. Fixed-precision (non-IEEE) numbers are mapped into either numeric or integer vectors.

Notice that many DBMS do not follow IEEE arithmetic, so there are potential problems with under/overflows and loss of precision.

See Also

Other DBIDriver generics: DBIDriver-class, dbConnect, dbDriver, dbGetInfo, dbIsValid, dbListConnections

Other DBIConnection generics: DBIConnection-class, dbDisconnect, dbExecute, dbExistsTable, dbGetException, dbGetInfo, dbGetQuery, dbIsValid, dbListFields, dbListResults, dbListTables, dbReadTable, dbRemoveTable, dbSendQuery, dbSendStatement

Examples

dbDataType(ANSI(), 1:5)
dbDataType(ANSI(), 1)
dbDataType(ANSI(), TRUE)
dbDataType(ANSI(), Sys.Date())
dbDataType(ANSI(), Sys.time())
dbDataType(ANSI(), Sys.time() - as.POSIXct(Sys.Date()))
dbDataType(ANSI(), c("x", "abc"))
dbDataType(ANSI(), list(raw(10), raw(20)))
dbDataType(ANSI(), I(3))

dbDataType(ANSI(), iris)

con <- dbConnect(RSQLite::SQLite(), ":memory:")

dbDataType(con, 1:5)
dbDataType(con, 1)
dbDataType(con, TRUE)
dbDataType(con, Sys.Date())
dbDataType(con, Sys.time())
dbDataType(con, Sys.time() - as.POSIXct(Sys.Date()))
dbDataType(con, c("x", "abc"))
dbDataType(con, list(raw(10), raw(20)))
dbDataType(con, I(3))

dbDataType(con, iris)

dbDisconnect(con)