RJDBC - Allows the use of JDBC to access databases from R
Package R docs
* All Java-related errors are signalled by throwing error
conditions. If a Java error occurred, the condition will be of
the class JDBC.exception with the Java class names of the
excption as subclasses. Such objects have following slots:
- desc: string, description of the operation error
- jex: Java object, reference to the Java exception object
- statement: string (or NULL), executed statement
This allows the programmatic use of tryCatch() to selectively
catch exceptions and/or to use further Java utilities, such as
* add schema= to dbExistsTable() (#84)
* check precision of numeric types and revert to string
representation if it is more than 15 to avoid loss of
precision at conversion time. (#83)
* NAs are supported in updates (#64)
* add findDrivers() function which uses Java Service Provider
mechanism (in Java 1.6 and higher) to find all JDBC driver
classes on the class path.
* dbConnection() used to always try DriverManager first
(without properties) and only on failure it would use the
driver. However, DriverManager is static and never updates the
driver list, so it is inherently unreliable. Therefore we now
prefer the driver if specified and DriverManager will only be
used if the driver is NULL. (inspired by #45)
* Use collect + join when fetch()ing results of unknown
length. This should improve performance for fetching results
with large number of rows. (mentioned in #50)
* Named arguments are removed from dbSendUpdate and query
calls when populating prepared statements to allow for future
named arguments in the methods.
* dbBegin() is implemented to disable auto-commit. Analogously,
dbRollback() and dbCommit() perform the corresponding
function and then re-enable auto-commit. (see also #58)
* dbReadTable() passes ... through to dbGetQuery
* re-use Java helper for subsequent fetch() calls on the same
result set which should make them more efficient.
* set has.completed only if the fetch() has encountered
end of the result set (#73)
* add use.label argument to fetch() - if set to FALSE
then column names are used instead of labels (#74)
* change both semantics and defaults for append=FALSE and
overwrite=FALSE in dbWriteTable() to match what is
documented in DBI: append=TRUE no longer requires the
existence of the target table and the options are mutally
exclusive (i.e. append=TRUE, overwrite=TRUE is illegal).
* dbWriteTable() also gains force=TRUE option (disabled by
default) which skips the existence check for the target and
proceeds with removal and/or insertion regardless. This can be
useful with append=TRUE where the target is not a table and
thus would not pass the dbExistsTable() check (see #27).
* dbRemoveTable() returns TRUE on success (#20). On failure it
will fail with an error if silent=FALSE (as it always did so
far) or return FALSE if silent=TRUE.
* JDBC errors are reported such that the statement is shown at
the end. Previously the statement preceded the JDBC error, so
long statements caused errors to be truncated (#32). This also
opens up the possibility of more structured error objects.
* n, block and use.label are now passed through from
dbGetQuery() to fetch() (#44)
* cosmetic changes to appease CRAN
* move java-src to java
* add schema= argument to dbGetTables() and dbListTables()
* support vectorized version of dbSendUpdate() which uses
batch-inserts for more efficient loading. Note that only
prepared statements work for now.
* use column labels instead of names (#36)
* dbColumnInfo() will return the column label in `name' and
column name in `field.name' (which is optional, for
* fix bug in dbUnloadDriver() returning NULL instead of FALSE
* added block argument to fetch() currently defaulting to 2048
which controls the fetch size.
Note that 0.2-4 has set this to the stride which was much too
big for some databases therefore it is now configurable.
* recover if setFetchSize() fails since some drivers don't take
it as a hint and fail regardless (issue #11)
* set fetch size to match the capacity for better performance
with some drivers. (thanks Jesse Rohland)
* close DB objects explicitly (issue #4) to avoid Oracle DB
running out of resources
* add support for dbHasCompleted() even in older DBI versions
* fix duplicate connection object (issue #1)
* add dbGetTables() and dbGetFields() which are similar to
dbListTable() and dbListFields() but return a full data frame
as obtained from the corresponding JDBC calls.
* add support for stored procedure call JDBC syntax.
Currently only IN parameters are supported since
DBI doesn't provide a way to retrieve OUT parameters.
* JDBC now uses path.expand() on the classPath components
* add support for dbWriteTable(..., append=TRUE)
* pass any additional arguments to dbConnect() as properties to
* use prepared statements only if parameters are passed,
otherwise use simple statements (this allows to work around
bugs in drivers that do not support prepared statements
* dbGetQuery() explicitly closes the statement before it returns
to work arround issues in the Teradata driver.
* use Java code to fetch results -- it should result in much higher
throughput in pulling result sets from the database. It is
also more efficient to use fetch() with n specified
(especially if you know it in advance) than relying on
n = -1. The latter will try first run with n = 32k and then
continue with n = 512k chunks and paste the results which is
inherently slow (still much faster than the 0.1-x way which
was fetching one record at a time).
* fix a typo in dbClearResult
* map NAs in query parameters into NULLs
(thanks to Axel Klenk)
* explicitly close statements right away (Oracle seems to need this)
(thanks to Axel Klenk)
* add "stat" slot (Statement object) to JDBCResult class to make sure
the statement lives long enough to not close the result set
* convert NULLs into NAs in numeric columns
* instantiate driver's class and use a call to `connect' as a
fall-back if the DriverManager fails to find a proper driver.
* fix SQL syntax in dbWriteTable (superfluous semicolon)
* fix a typo in prepared statement code
(thanks to Carl Grant for the last two bugfixes)
* added SQL error information to most JDBC errors
* use .jfindClass to load drivers
* remove beforeFirst() as some DBMS don't like it. This also
allows a sequential use of fetch() with a limit to load data
* fix a bug that caused NULL entries in string columns to fail
* fix dbDisconnect return value and update manuals
* added pre-compiled statements and proper dbWriteTable
0.1-0 (not released)
* drop pgsql access, switch to DBI
* add direct insert support for pgsql
* added converson of tables to data.frames
* added type conversion (int, double, string)
* first public release