dbGetInfo {DBI} | R Documentation |
Extract meta-data associated with various objects
dbGetInfo(dbObj, ...) # meta-data for any DBIObject dbGetDBIVersion(...) # DBI version dbGetStatement(res, ...) # statement that produced result "res" dbGetRowCount(res, ...) # number of rows fetched so far dbGetRowsAffected(res, ...) # number of affected rows (e.g., DELETE) dbColumnInfo(res, ...) # result set data types dbHasCompleted(res, ...) # are there more rows to fetch on "res"?
dbObj |
any object that implements some functionality in the R/Splus interface to databases (a driver, a connection or a result set). |
res |
refers to a DBIResult object.
|
... |
any driver-specific arguments. |
These functions implement a minimal set of meta-data describing the most important aspects of the R/Splus to DBMS interface.
The dbGetInfo
works very similarly to the function
options
in that it attempts to extract what the user may
request, possibly NULL if it can't locate the specific piece
of meta-data.
dbGetDBIVersion
returns a character string with the version
of the database interface API.
dbGetInfo
produces either a character vector or a named list
of (name, value) pairs.
dbGetStatement
returns a character string with the statement
associated with the result set res
.
dbGetRowCount
returns the number of rows fetched so far.
dbGetRowsAffected
returns the number of affected rows (e.g.,
how many rows were deleted, inserted). Some drivers may set this
to the total number of rows a query produces.
dbColumnInfo
returns a data.frame with one row per output field
in res
. The columns should report field name, field data type,
scale and precision (as understood by the DBMS engine), whether the
field can store NULL
values, and possibly other DBMS-specific
information.
dbHasCompleted
a logical describing whether the operations has
been completed by the DBMS or not.
Meta-data associated with a driver should include the version of the package, plus the version of the underlying client library. Connection objects should report the version of the DBMS engine, database name, user, possibly password, etc. Results should include the statement being executed, how many rows have been fetched so far (in the case of queries), how many rows were affected (deleted, inserted, changed, or total number of records to be fetched).
See the Database Interface definition document
DBI.pdf
in the base directory of this package
or http://developer.r-project.org/db.
dbDriver
,
dbConnect
,
dbSendQuery
,
dbGetQuery
,
fetch
,
dbCommit
,
dbGetInfo
,
dbListTables
,
dbReadTable
.
## Not run: drv <- dbDriver("SQLite") con <- dbConnect(drv) dbListTables(con) rs <- dbSendQuery(con, query.sql) dbGetStatement(rs) dbHasCompleted(rs) info <- dbGetInfo(rs) names(dbGetInfo(drv)) # DBIConnection info names(dbGetInfo(con)) # DBIResult info names(dbGetInfo(rs)) ## End(Not run)