search for: dbmss

Dear List, Would anyone know how to perform prepared queries with ROBC ? I had a shot with some of the internal (non-exported) functions of the package but ended up with a segfault, so I prefer asking around before experimenting further... Thanks, Laurent

I have a general question about R's usage or memory and what limits exist on the size of datasets it can deal with. My understanding was that all object in a session are held in memory. This implies that you're limited in the size of datasets that you can process by the amount of memory you've got access to (be it physical or paging). Is this true? Or does R store objects on disk

Dear alls, Could someone tell me how to select a subset of string observations (e.g. "females" in a sex column) with sqlQuery in the RODBC library? Indeed, I'm trying to select a subset of observations on my access database with: female<-sqlQuery(mychannel,"SELECT Micromammiferes.sex FROM Micromammiferes WHERE (((Micromammiferes.sex)="females"));") The sql

...ly linked with the name of the column of dates in my dataframe, which was formerly "date" and which I changed into "dates". Since my exporting worked (?). The varTypes argument works as described in the sqlSave() help page: "an optional named character vector giving the DBMSs datatypes to be used for some (or all) of the columns if a table is to be created". However, I have only been able to export my dataframe with the "dates" column as Date; not as POSIX, though dates are in POSIX when importing into R with sqlQuery (?). I have still questions abou...

...o estoy entendiendo mal, lo q deseo hacer no se trata de configurar los parametros SQL, sino solo de colocar un vector en el argumento VarTypes de la funcion sqlSave. El manual especifica esa opcion, pero no da ningun ejemplo de como usarla. *varTypes an optional named character vector giving the DBMSs datatypes to be used for* *some (or all) of the columns if a table is to be created.* En este pdf https://cran.r-project.org/web/packages/RODBC/vignettes/RODBC.pdf, solo se hace referencia al argumento en este parrafo *4.1 Data types when saving a data frame When sqlSave creates a table, there is...

All; I know that there are probably several solutions to this problem, but what I am trying to do is provide some redundancy for my customers CDR data. I know that doing simple backups of MySQL is probably the easiest way to go, but I'm thinking that there may be some benefit to simultaneously writing the CDR data to multiple servers at once. However, I'm drawing a blank on this one.

Dear useRs, I would like to query an Access database through R based on a date attribute but, unfortunately, I fail to do so. For example, the table test_table of the test.mdb looks like: ID cd market competitor dd price 1 1 2007-11-20 atl-bos delta 2007-11-20 210 2 2 2007-11-20 atl-bos delta 2007-11-21 190 3 3 2007-11-20 atl-bos delta 2007-11-22

...d to do is to disable referential integrity. Referential integrity is but one specific case of a whole set of database level integrity constraints (including primary keys, uniqueness constraints, etc.). Few databases support SQL 92 assertions (see http://stackoverflow.com/questions/6368349/why-dont-dbmss-support-assertion), so most developers/DBAs that want more complicated database level integrity constraints implement them via triggers. In addition, triggers can also be used to implement automatic caching of computer or derived data within the database (for instance, updating a table that keeps t...

We are using MySQL, and love the idea of using zfs for this. We are used to using Direct I/O to bypass file system caching (let the DB do this). Does this exist for zfs? This message posted from opensolaris.org

We''re pleased to announce version 0.0.3 of Net::LDAP, the first pure-Ruby LDAP library. Net::LDAP intends to be a feature-complete LDAP client which can access as much as possible of the functionality of the most-used LDAP server implementations. This library does not wrap any existing native-code LDAP libraries, creates no Ruby extensions, and has no dependencies external to Ruby.

Hi all, I''m doing my first xen, running with 3 domU perfect. I need to know which way to backup domU to restore these to another server if i''ve problem with this machine. There are 3 LVM with 10G in VolGroup01 for each domU, with each of these partitions: /dev/xvda3            8,7G  1,4G  6,9G  17%

Buen dia Javier, muchas gracias por tu ayuda y el script compartido. Me va a servir como ayuda para seguir aprendiendo sobre RODBC pero no encuentro una solucion para este problema puntual de poder definir el tipo y ancho de las variables, q segun creo se hace con el argumento varTypes. Si alguien tien algun ejemplo donde haya usado la SqlSave y VarTypes, me sera de gran ayuda. Abrazo a todos

...ess This CRAN package provides access to any Open DataBase Connectivity (ODBC) accessible database. . The package should be platform independent and provide access to any database for which a driver exists. It has been tested with MySQL and PostgreSQL on both Linux and Windows (and to those DBMSs on Linux hosts from R under Windows), Microsoft Access, SQL Server and Excel spreadsheets (read-only), and users have reported success with connections to Oracle and DBase. . Usage is covered in the R Data Import/Export manual (available via the r-doc-pdf, r-doc-html and r-doc-info packages)...

Here''s the text of a quick note I''ve added to the Inheritance wiki page. I''m actually proposing that it would be a good idea to drop automatic single table inheritance and force people to declare it explicitly. There are two reasons for this: 1. Implicitly doing it unnecessarially limits your use of inheritance where you really need it: in your object-oriented

Performace hits? Integration with existing applications? Security? Bugs? Memory use? -Ben Lisbakken -- Posted via http://www.ruby-forum.com/.