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Build a Ruby App with CockroachDB
Learn how to use CockroachDB from a simple Ruby application with the pg client driver.
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This tutorial shows you how build a simple Ruby application with CockroachDB using a PostgreSQL-compatible driver or ORM. We've tested and can recommend the Ruby pg driver and the ActiveRecord ORM, so those are featured here.

Before You Begin

Make sure you have already installed CockroachDB.

Step 1. Install the Ruby pg driver

To install the Ruby pg driver, run the following command:

$ gem install pg

{% include app/common-steps.md %}

Step 5. Run the Ruby code

Now that you have a database and a user, you'll run code to create a table and insert some rows, and then you'll run code to read and update values as an atomic transaction.

Basic Statements

First, use the following code to connect as the maxroach user and execute some basic SQL statements, creating a table, inserting rows, and reading and printing the rows.

Copy the code or download it directly.

{% include app/basic-sample.rb %}

Then run the code:

$ ruby basic-sample.rb

The output should be:

Initial balances:
{"id"=>"1", "balance"=>"1000"}
{"id"=>"2", "balance"=>"250"}

Transaction (with retry logic)

Next, use the following code to again connect as the maxroach user but this time execute a batch of statements as an atomic transaction to transfer funds from one account to another, where all included statements are either committed or aborted.

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{{site.data.alerts.callout_info}}With the default SERIALIZABLE isolation level, CockroachDB may require the client to retry a transaction in case of read/write contention. CockroachDB provides a generic retry function that runs inside a transaction and retries it as needed. You can copy and paste the retry function from here into your code.{{site.data.alerts.end}}

{% include app/txn-sample.rb %}

Then run the code:

$ ruby txn-sample.rb

To verify that funds were transferred from one account to another, use the built-in SQL client:

$ cockroach sql --insecure -e 'SELECT id, balance FROM accounts' --database=bank
+----+---------+
| id | balance |
+----+---------+
|  1 |     900 |
|  2 |     350 |
+----+---------+
(2 rows)

What's Next?

Read more about using the Ruby pg driver.

You might also be interested in using a local cluster to explore the following core CockroachDB features: