build-a-php-app-with-cockroachdb.md

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Build a PHP App with CockroachDB	Learn how to use CockroachDB from a simple PHP application with a low-level client driver.	false	true

This tutorial shows you how build a simple PHP application with CockroachDB using a PostgreSQL-compatible driver. We've tested and can recommend the php-pgsql driver, so that driver is featured here.

Before You Begin

Make sure you have already installed CockroachDB.

Step 1. Install the php-pgsql driver

Install the php-pgsql driver as described in the official documentation.

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

Step 5. Create a table in the new database

As the maxroach user, use the built-in SQL client to create an accounts table in the new database.

$ cockroach sql --insecure \
--database=bank \
--user=maxroach \
-e 'CREATE TABLE accounts (id INT PRIMARY KEY, balance INT)'

Step 6. Run the PHP 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, inserting rows and reading and printing the rows.

You can copy the code or download it directly.

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

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.

You can copy the code or download it directly.

{{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.php %}

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 php-pgsql driver.

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

• Data Replication
• Fault Tolerance & Recovery
• Automatic Rebalancing