This tutorial shows you how build a simple C++ application with CockroachDB using a PostgreSQL-compatible driver.
We have tested the C++ libpqxx driver enough to claim beta-level support, so that driver is featured here. If you encounter problems, please open an issue with details to help us make progress toward full support.
Before you begin
Make sure you have already installed CockroachDB.
Step 1. Install the libpqxx driver
Install the C++ libpqxx driver as described in the official documentation.
Step 2. Start a single-node cluster
For the purpose of this tutorial, you need only one CockroachDB node running in insecure mode:
$ cockroach start \
--insecure \
--store=hello-1 \
--listen-addr=localhost
Step 3. Create a user
In a new terminal, as the root user, use the cockroach user command to create a new user, maxroach.
$ cockroach user set maxroach --insecure
Step 4. Create a database and grant privileges
As the root user, use the built-in SQL client to create a bank database.
$ cockroach sql --insecure -e 'CREATE DATABASE bank'
Then grant privileges to the maxroach user.
$ cockroach sql --insecure -e 'GRANT ALL ON DATABASE bank TO maxroach'
Step 5. Run the C++ 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.
Download the basic-sample.cpp file, or create the file yourself and copy the code into it.
{% include {{ page.version.version }}/app/basic-sample.cpp %}
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.
{{site.data.alerts.callout_info}} 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}}
Download the txn-sample.cpp file, or create the file yourself and copy the code into it.
{% include {{ page.version.version }}/app/txn-sample.cpp %}
After running the code, use the built-in SQL client to verify that funds were transferred from one account to another:
$ 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 C++ libpqxx driver.
You might also be interested in using a local cluster to explore the following CockroachDB benefits: