DBI defines an interface for communication between R and relational database management systems. All classes in this package are virtual and need to be extended by the various R/DBMS implementations (so-called DBI backends).

Definition

A DBI backend is an R package which imports the DBI and methods packages. For better or worse, the names of many existing backends start with ‘R’, e.g., RSQLite, RMySQL, RSQLServer; it is up to the backend author to adopt this convention or not.

DBI classes and methods

A backend defines three classes, which are subclasses of DBIDriver, DBIConnection, and DBIResult. The backend provides implementation for all methods of these base classes that are defined but not implemented by DBI. All methods defined in DBI are reexported (so that the package can be used without having to attach DBI), and have an ellipsis ... in their formals for extensibility.

Construction of the DBIDriver object

The backend must support creation of an instance of its DBIDriver subclass with a constructor function. By default, its name is the package name without the leading ‘R’ (if it exists), e.g., SQLite for the RSQLite package. However, backend authors may choose a different name. The constructor must be exported, and it must be a function that is callable without arguments. DBI recommends to define a constructor with an empty argument list.

See also

Important generics: dbConnect(), dbGetQuery(), dbReadTable(), dbWriteTable(), dbDisconnect()

Formal specification (currently work in progress and incomplete): vignette("spec", package = "DBI")

Examples

RSQLite::SQLite()
#> Warning: replacing previous import ‘DBI::coerce’ by ‘methods::coerce’ when loading ‘RSQLite’
#> <SQLiteDriver>