Analyze OData Services in R via ODBC

Access OData services with pure R script and standard SQL. You can use the CData ODBC Driver for OData and the RODBC package to work with remote OData services in R. By using the CData Driver, you are leveraging a driver written for industry-proven standards to access your data in the popular, open-source R language. This article shows how to use the driver to execute SQL queries to OData services and visualize OData services in R.

Getting Started

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Install R

You can complement the driver's performance gains from multi-threading and managed code by running the multithreaded Microsoft R Open or by running R linked with the BLAS/LAPACK libraries. This article uses Microsoft R Open (MRO).

Connect to OData as an ODBC Data Source

Information for connecting to OData follows, along with different instructions for configuring a DSN in Windows and Linux environments.

The User and Password properties, under the Authentication section, must be set to valid OData user credentials. In addition, specify a URL to a valid OData server organization root or OData services file.

When you configure the DSN, you may also want to set the Max Rows connection property. This will limit the number of rows returned, which is especially helpful for improving performance when designing reports and visualizations.

Windows

If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.

Linux

If you are installing the CData ODBC Driver for OData in a Linux environment, the driver installation predefines a system DSN. You can modify the DSN by editing the system data sources file (/etc/odbc.ini) and defining the required connection properties.

/etc/odbc.ini

[CData OData Source]
Driver = CData ODBC Driver for OData
Description = My Description
URL = http://services.odata.org/V4/Northwind/Northwind.svc
UseIdUrl = True
OData Version = 4.0
Data Format = ATOM

For specific information on using these configuration files, please refer to the help documentation (installed and found online).

Load the RODBC Package

To use the driver, download the RODBC package. In RStudio, click Tools -> Install Packages and enter RODBC in the Packages box.

After installing the RODBC package, the following line loads the package:

library(RODBC)

Note: This article uses RODBC version 1.3-12. Using Microsoft R Open, you can test with the same version, using the checkpoint capabilities of Microsoft's MRAN repository. The checkpoint command enables you to install packages from a snapshot of the CRAN repository, hosted on the MRAN repository. The snapshot taken Jan. 1, 2016 contains version 1.3-12.

library(checkpoint)
checkpoint("2016-01-01")

Connect to OData Services as an ODBC Data Source

You can connect to a DSN in R with the following line:

conn <- odbcConnect("CData OData Source")

Schema Discovery

The driver models OData APIs as relational tables, views, and stored procedures. Use the following line to retrieve the list of tables:

sqlTables(conn)

Execute SQL Queries

Use the sqlQuery function to execute any SQL query supported by the OData API.

orders <- sqlQuery(conn, "SELECT Orders.Freight, Customers.ContactName FROM Customers INNER JOIN Orders ON Customers.CustomerId=Orders.CustomerId", believeNRows=FALSE, rows_at_time=1)

You can view the results in a data viewer window with the following command:

View(orders)

Plot OData Services

You can now analyze OData services with any of the data visualization packages available in the CRAN repository. You can create simple bar plots with the built-in bar plot function:

par(las=2,ps=10,mar=c(5,15,4,2))
barplot(orders$Freight, main="OData Orders", names.arg = orders$OrderName, horiz=TRUE)

👁 A basic bar plot. (Salesforce is shown.)