[R] problems accessing MS Access 2003 database with RODBC
Boris.Vasiliev at forces.gc.ca
Boris.Vasiliev at forces.gc.ca
Wed Apr 28 22:38:26 CEST 2010
> -----Original Message-----
> From: Marc Schwartz [mailto:marc_schwartz at me.com]
> Sent: Monday, 26, April, 2010 13:47 PM
> To: Vasiliev B at CEFCOM HQ at Ottawa-Hull
> Cc: r-help at r-project.org; Ripley Prof Brian
> Subject: Re: [R] problems accessing MS Access 2003 database with RODBC
>
> On Apr 26, 2010, at 12:40 PM, Marc Schwartz wrote:
>
> > On Apr 26, 2010, at 12:11 PM, Boris.Vasiliev at forces.gc.ca wrote:
> >
> >> Dear users,
> >>
> >> I am trying to access a Microsoft Access database from R
> using RODBC
> >> package but I have had little success. The setup works with isql,
> >> RODBC seems to connect to the database, but RODBC does not
> recognize
> >> the data in the database. Can anybody advise where I am
> going wrong?
> >>
> >> I am using R version 2.10.1 on Ubuntu 8.04. ODBC version is 2.2.11.
> >> Mdbtools
> >> version is 0.6pre1. RODBC version is 1.3.1. Test database
> with one
> >> table was created in MS Access 2003.
> >>
> >> The ODBC configuration files are
> >>
> >> /etc/odbcinst.ini:
> >> [Microsoft Access Driver (*.mdb)]
> >> Description = MDB Tools ODBC drivers
> >> Driver = /usr/lib/libmdbodbc.so.0
> >> Setup =
> >> FileUsage = 1
> >> CPTimeout =
> >> CRReuse =
> >>
> >> /home/vasiliev/.odbc.ini:
> >> [test_db]
> >> Description = test events database
> >> Driver = Microsoft Access Driver (*.mdb) Database =
> >> /home/vasiliev/siginci/data/test_db.mdb
> >> Trace = Yes
> >> TraceFile = /home/vasiliev/odbc.log
> >>
> >> When I test the set-up with isql it seems to work:
> >>
> >> isql -v -m10 test_db
> >> +---------------------------------------+
> >> | Connected! |
> >> | |
> >> | sql-statement |
> >> | help [tablename] |
> >> | quit |
> >> | |
> >> +---------------------------------------+
> >> SQL> help
> >> +-----------+-----------+-----------+-----------+-----------+
> >> | TABLE_CAT | TABLE_SCHE| TABLE_NAME| TABLE_TYPE| REMARKS |
> >> +-----------+-----------+-----------+-----------+-----------+
> >> | | | MSysObject| SYSTEM TAB| |
> >> | | | MSysACEs | SYSTEM TAB| |
> >> | | | MSysQuerie| SYSTEM TAB| |
> >> | | | MSysRelati| SYSTEM TAB| |
> >> | | | MSysAccess| SYSTEM TAB| |
> >> | | | tblA1 | TABLE | |
> >> | | | MSysAccess| SYSTEM TAB| |
> >> +-----------+-----------+-----------+-----------+-----------+
> >> SQLRowCount returns 7
> >> 7 rows fetched
> >> SQL> help tblA1
> >>
> +-----------+-----------+-----------+-----------+----------+--
> ---------+
> >> -----------+
> >> | TABLE_CAT | TABLE_SCHE| TABLE_NAME| COLUMN_NAM| DATA_TYPE|
> >> | TYPE_NAME |
> >> COLUMN_SIZ|
> >>
> +-----------+-----------+-----------+-----------+----------+--
> ---------+
> >> -----------+
> >> | | | tblA1 | ID | 4
> | FIX ME |
> >> |
> >> | | | tblA1 | Row | 5
> | FIX ME |
> >> |
> >> | | | tblA1 | Value | 4
> | FIX ME |
> >> |
> >>
> +-----------+-----------+-----------+-----------+----------+--
> ---------+
> >> -----------+
> >> SQLRowCount returns 3
> >> 3 rows fetched
> >> SQL> select * from tblA1
> >> +-----------+-------+-----------+
> >> | ID | Row | Value |
> >> +-----------+-------+-----------+
> >> | 1 | 1 | 2 |
> >> | 2 | 10 | 10 |
> >> | 3 | 30 | 30 |
> >> | 4 | 40 | 40 |
> >> +-----------+-------+-----------+
> >> SQLRowCount returns 4
> >> 4 rows fetched
> >>
> >> However, when the connection is opened in R, it appears to
> be empty.
> >> DBMS details
> >> are not recognized; table and data are unavailable:
> >>
> >>> ch <- odbcConnect("test_db")
> >>> odbcGetInfo(ch)
> >> DBMS_Name DBMS_Ver Driver_ODBC_Ver Data_Source_Name
> >> "" "" "" "test_db"
> >> Driver_Name Driver_Ver ODBC_Ver Server_Name
> >> "test_db" "test_db" "03.52" "03.52"
> >>> sqlTables(ch)
> >> [1] TABLE_CAT TABLE_SCHEM TABLE_NAME TABLE_TYPE REMARKS
> >> <0 rows> (or 0-length row.names)
> >>
> >> Does anybody know what I am doing incorrectly?
> >> Sincerely,
> >> Boris.
> >
> >
> > As far as I know, the use of mdb-tools for Access via RODBC
> on Linux is not supported. A search of the archives reveals
> this post from Prof. Ripley from 2004:
> >
> > *http://tolstoy.newcastle.edu.au/R/help/04/11/6585.html
> >
> > I am presuming that this is still the case, though I am
> cc:ing Prof. Ripley for confirmation.
> >
> > In that same thread, there is a post from David Whiting
> that you might find helpful as an alternative, presuming that
> the information is still of value 6 years hence.
>
>
> FYI, I found another possible option which is the mdb.get()
> function in Frank Harrell's Hmisc package on CRAN.
>
> Note that at the moment, some of the CRAN network is down:
>
> https://stat.ethz.ch/pipermail/r-help/2010-April/236583.html
>
> HTH,
>
> Marc
>
>
Marc,
Thank you very much for your suggestions and apologies for tardy reply.
To summarize the discussion, it seems that there are several options to
access Microsoft Access databases from R on Linux
1. Use an ODBC driver for Microsoft Access databases other than the
driver in mdbtools. I think EasySoft offers such driver but it is
relatively expensive ~400 pounds/licence.
2. Convert the database into a MySQL database using mdbtools and tools
build on top of it. Although appealing, this implies existence of two
databases with the same data.
3. Use mdb.get() from Hmisc package to import entire tables from the
database into dataframes.
4. Switch to R on Windows where ODBC driver for Microsoft Access
databases is well-behaved and freely available.
For my application, option 3 seems to suit best. My database is
relatively small (~200 thousand records), has only few tables, and speed
is not comprised greatly when I import everything into R.
Once again many thanks for your help.
Regards,
Boris.
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