Connect: Add R

Author: amotl

docs/connect/index.md

@@ -97,6 +97,18 @@ CrateDB drivers and adapters for supported programming languages, frameworks, an
 {fab}`python`
 ::::
 
+::::{grid-item-card} R
+:link: connect-r
+:link-type: ref
+:link-alt: Connect to CrateDB using R
+:padding: 3
+:text-align: center
+:class-card: sd-pt-3
+:class-body: sd-fs-1
+:class-title: sd-fs-6
+{fab}`r-project`
+::::
+
 ::::{grid-item-card} Ruby
 :link: connect-ruby
 :link-type: ref
@@ -186,6 +198,7 @@ java
 javascript
 php
 python
+r/index
 ruby
 natural
 All drivers <drivers>

docs/connect/r/index.md

@@ -0,0 +1,90 @@
+(connect-r)=
+
+# R
+
+:::{div} sd-text-muted
+Connect to CrateDB from R applications and notebooks.
+:::
+
+:::{rubric} About
+:::
+
+The [RPostgres] package is the canonical C++ Interface to PostgreSQL.
+An alternative is the [RPostgreSQL] package, written in C.
+RPostgres is actively maintained and often preferred.
+
+:::{rubric} Synopsis
+:::
+
+`example.r`
+```r
+# Connect to CrateDB from R, using the "RPostgres: C++ Interface to PostgreSQL".
+# https://cran.r-project.org/web/packages/RPostgres/
+
+# Install the Postgres library on demand.
+if (!requireNamespace("RPostgres", quietly = TRUE)) {
+    install.packages("RPostgres", repos="https://cran.r-project.org")
+}
+
+# Load the DBI and Postgres libraries.
+library(DBI)
+library(RPostgres)
+
+# Connect to database.
+conn <- dbConnect(RPostgres::Postgres(),
+                  host = "localhost",
+                  port = 5432,
+                  sslmode = "disable",
+                  user = "crate",
+                  password = "crate",
+                  dbname = "doc"
+                  )
+on.exit(DBI::dbDisconnect(conn), add = TRUE)
+
+# Invoke a basic select query.
+res <- dbGetQuery(conn, "SELECT * FROM sys.summits ORDER BY height DESC LIMIT 10;")
+print(res)
+```
+
+Start CrateDB using Docker or Podman, then invoke the example program.
+```shell
+docker run --rm --publish=5432:5432 crate '-Cdiscovery.type=single-node'
+```
+```shell
+Rscript example.r
+```
+
+
+:::{rubric} CrateDB Cloud
+:::
+
+For connecting to CrateDB Cloud, use `sslmode = "require"`, and
+replace username, password, and hostname with values matching
+your environment.
+```r
+conn <- dbConnect(RPostgres::Postgres(),
+                  host = "testcluster.cratedb.net",
+                  port = 5432,
+                  sslmode = "require",
+                  user = "admin",
+                  password = "password",
+                  dbname = "doc"
+                  )
+```
+
+## Example
+
+:::{card}
+:link: https://github.com/crate/cratedb-examples/tree/main/by-language/r
+:link-type: url
+{material-outlined}`play_arrow;2em`
+Connect to CrateDB and CrateDB Cloud using R.
++++
+Demonstrates basic examples that use the R RPostgres and RPostgreSQL packages.
+:::
+
+[![R](https://github.com/crate/cratedb-examples/actions/workflows/lang-r.yml/badge.svg)](https://github.com/crate/cratedb-examples/actions/workflows/lang-r.yml)
+
+
+[RPostgres]: https://cran.r-project.org/web/packages/RPostgres/
+[RPostgreSQL]: https://cran.r-project.org/web/packages/RPostgreSQL/