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.
dbDataType(dbObj, obj, ...)"dbDataType"(dbObj, obj, ...)
- A object inheriting from
- An R object whose SQL type we want to determine.
- Other arguments passed on to methods.
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.
A character string specifying the SQL data type for
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)