Simple C Application for YugabyteDB

This application connects to your YugabyteDB instance via the libpq driver and performs basic SQL operations. The instructions below are provided for YugabyteDB Aeon deployments. If you use a different type of deployment, then update the sample-app.c file with proper connection parameters.

Prerequisites

• A 32-bit (x86) or 64-bit (x64) architecture machine. Use Rosetta to build and run on the Apple silicon.
• gcc 4.1.2 or later, clang 3.4 or later installed.
• libpq driver.
• OpenSSL library (used by libpq to establish secured SSL connections).
• Command line tool or your favourite IDE, such as Visual Studio Code.

Start YugabyteDB Aeon Cluster

• Start YugabyteDB Aeon instance. You can use the free tier at no cost.
• Add an IP address of your machine/laptop to the IP allow list

Clone Application Repository

Clone the repository and change dirs into it:

git clone https://github.com/YugabyteDB-Samples/yugabyte-simple-c-app.git && cd yugabyte-simple-c-app

Provide Cluster Connection Parameters

Locate and define the following configuration-related macros in the sample-app.c file:

• HOST - the hostname of your instance.
• USER - the username for your instance.
• PASSWORD - the database password.
• SSL_MODE - the SSL mode to use. YugabyteDB Aeon requires SSL connections; use verify-full.
• SSL_ROOT_CERT - a full path to your CA root cert (for example, /Users/dmagda/certificates/root.crt).

Note, you can easily find all the settings on the YugabyteDB Aeon dashboard:

Run the Application

1. Install the libpq driver via Homebrew package manager or using a different method.

2. Replace the {libpq-install-dir} placeholder with your libpq installation root dir and build the application with gcc or clang:

   gcc sample-app.c -o sample-app -I{libpq-install-dir}/libpq/include -L{libpq-install-dir}/libpq/lib -lpq

3. Run the application:

   ./sample-app

Upon successful execution, you will see output similar to the following:

>>>> Connecting to YugabyteDB!
>>>> Connected to YugabyteDB!
>>>> Successfully created table DemoAccount.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 10000
name = John, age = 28, country = Canada, balance = 9000
>>>> Transferred 800 between accounts.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 9200
name = John, age = 28, country = Canada, balance = 9800

Explore Application Logic

Congrats! You've successfully executed a simple C app that works with YugabyteDB.

Now, explore the source code of sample-app.c:

1. connect function - establishes a connection with your cloud instance via the libpq driver.
2. createDatabase function - creates a table and populates it with sample data.
3. selectAccounts function - queries the data with SQL SELECT statements.
4. transferMoneyBetweenAccounts function - updates records consistently with distributed transactions.

Questions or Issues?

Having issues running this application or want to learn more from Yugabyte experts?

Join our Slack channel, or raise a question on StackOverflow and tag the question with yugabytedb!