Analyze SQL Server Data in R via ODBC

Access SQL Server data with pure R script and standard SQL. You can use the CData ODBC Driver for SQL Server and the RODBC package to work with remote SQL Server data 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 SQL Server data and visualize SQL Server data in R.

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 SQL Server as an ODBC Data Source

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

Connecting to Microsoft SQL Server

Connect to Microsoft SQL Server using the following properties:

• Server: The name of the server running SQL Server.
• User: The username provided for authentication with SQL Server.
• Password: The password associated with the authenticating user.
• Database: The name of the SQL Server database.

Connecting to Azure SQL Server and Azure Data Warehouse

You can authenticate to Azure SQL Server or Azure Data Warehouse by setting the following connection properties:

• Server: The server running Azure. You can find this by logging into the Azure portal and navigating to "SQL databases" (or "SQL data warehouses") -> "Select your database" -> "Overview" -> "Server name."
• User: The name of the user authenticating to Azure.
• Password: The password associated with the authenticating user.
• Database: The name of the database, as seen in the Azure portal on the SQL databases (or SQL warehouses) page.

SSH Connectivity for SQL Server

You can use SSH (Secure Shell) to authenticate with SQL Server, whether the instance is hosted on-premises or in supported cloud environments. SSH authentication ensures that access is encrypted (as compared to direct network connections).

SSH Connections to SQL Server in Password Auth Mode

To connect to SQL Server via SSH in Password Auth mode, set the following connection properties:

• User: SQL Server User name
• Password: SQL Server Password
• Database: SQL Server database name
• Server: SQL Server Server name
• Port: SQL Server port number like 3306
• UserSSH: "true"
• SSHAuthMode: "Password"
• SSHPort: SSH Port number
• SSHServer: SSH Server name
• SSHUser: SSH User name
• SSHPassword: SSH Password

SSH Connections to SQL Server in Public Key Auth Mode

To connect to SQL Server via SSH in Password Auth mode, set the following connection properties:

• User: SQL Server User name
• Password: SQL Server Password
• Database: SQL Server database name
• Server: SQL Server Server name
• Port: SQL Server port number like 3306
• UserSSH: "true"
• SSHAuthMode: "Public_Key"
• SSHPort: SSH Port number
• SSHServer: SSH Server name
• SSHUser: SSH User name
• SSHClientCret: the path for the public key certificate 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 SQL Server 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 SQL Source]
Driver = CData ODBC Driver for SQL Server
Description = My Description
User = myUser
Password = myPassword
Database = NorthWind
Server = myServer
Port = 1433

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 SQL Server Data as an ODBC Data Source

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

conn <- odbcConnect("CData SQL Source")

Schema Discovery

The driver models SQL Server 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 SQL Server API.

orders <- sqlQuery(conn, "SELECT ShipName, Freight FROM Orders", believeNRows=FALSE, rows_at_time=1)

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

View(orders)

Plot SQL Server Data

You can now analyze SQL Server data 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$Freight, main="SQL Server Orders", names.arg = orders$ShipName, horiz=TRUE)

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