dbDataType
Determine the SQL data type of an object
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
DBIDriverorDBIConnection - obj
- An R object whose SQL type we want to determine.
- ...
- Other arguments passed on to methods.
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.
Value
-
A character string specifying the SQL data type for
obj.
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
library(DBI)
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)
