PHP SQLite: Working with SQLite Databases using PHP

SQLite is a powerful, serverless database engine that integrates seamlessly with PHP. By combining these technologies, developers can build feature-rich web applications with efficient data management.

In this comprehensive guide, you’ll learn hands-on how to harness the potential of PHP and SQLite to develop robust web database solutions.

We’ll start from the ground up by creating a simple table, populating it with sample data, and running queries. Then, we’ll level up to transactions, prepared statements, and error handling. Real-world code snippets and outputs are included every step of the way.

By the end, you’ll have the complete toolkit to build and deploy your own PHP-based web apps powered by SQLite databases. Let’s dive in!

Creating a SQLite Basic Table using PHP

First, we need to connect to a SQLite database. This will create a new database if it doesn’t already exist:

$db = new PDO('sqlite:sample.db');

Next, let’s create a table called users with some fields:

$query = "CREATE TABLE users (
  id INTEGER PRIMARY KEY,
  name TEXT NOT NULL,
  email TEXT UNIQUE NOT NULL
)";

$db->exec($query);

We now have an empty users table ready to store data.

Inserting Sample Data in SQLite with PHP

Let’s populate the table with some records. We can insert rows by passing an SQL INSERT statement:

$query = "INSERT INTO users (name, email) VALUES 
  ('John', '[email protected]'),
  ('Sarah', '[email protected]')";

$db->exec($query);  

This inserts two new users into the table.

Fetching and Displaying Data from SQLite with PHP

To retrieve the contents of the users table, we can query it like so:

$sql = 'SELECT * FROM users';
foreach ($db->query($sql) as $row) {
  print_r($row); 
}

Which outputs:

Array ( 
  [id] => 1
  [name] => John
  [email] => [email protected] 
)

Array (
  [id] => 2
  [name] => Sarah 
  [email] => [email protected]
)

And there we have it – the two rows we inserted, neatly fetched and displayed!

We’ve now covered the basics of creating a SQLite table in PHP, inserting records, and querying the contents. Pretty simple right?

In the next sections we’ll explore more advanced functionality…

Transactions for Data Consistency in SQLite with PHP

When making multiple inserts, updates or deletes, you may need transactions to ensure database consistency.

Transactions allow you to execute SQL statements as one atomic operation – either all succeed or all fail, keeping the data integrity intact.

Here is an example transaction that transfers $100 between two accounts:

try {
  $db->beginTransaction();
  
  $sql = "UPDATE accounts SET balance = balance - 100 WHERE id = 1"; 
  $db->exec($sql);
  
  $sql = "UPDATE accounts SET balance = balance + 100 WHERE id = 2";
  $db->exec($sql);

  $db->commit();
  echo "Transfer successful";
  
} catch (Exception $e) {
   
  $db->rollBack();
  echo "Transfer failed";

}

This runs both updates under one transaction. If either fails, the database rolls back any changes made, keeping balances unchanged.

Transactions are vital whenever making multiple linked changes to ensure a consistent dataset.

Preparing Reusable Statements in SQLite with PHP

Passing raw SQL statements directly is convenient at first, but can quickly become messy. Prepared statements offer a cleaner way to execute queries.

First, we initialize a prepared statement by passing SQL with placeholders:

$stmt = $db->prepare('SELECT * FROM users WHERE id = ?'); 

Next, we can fill the placeholders and execute it:

$id = 2;
$stmt->bindParam(1, $id); 

$stmt->execute(); 

while($row = $stmt->fetch()) {
  print_r($row);
}

Which gives the output:

Array ( 
  [id] => 2
  [name] => Sarah
  [email] => [email protected] 
)

The main benefits here are:

• Avoid repeatedly writing similar SQL statements
• Automatically handle quoting and escaping values
• Improve security and prevent SQL injection attacks

So by using parameters and binding values, prepared statements make working with data much more convenient and secure.

Handling Errors Gracefully in SQLite with PHP

When dealing with databases, sometimes things go wrong! Let’s look at some common error-handling approaches.

First, we can check for errors immediately after running a query:

$sql = "INSERT INTO users (name) VALUES ('Tom')";

if (!$db->exec($sql)) {
  echo "Insert failed: " . $db->lastErrorMsg();
} else {
  echo "Insert succeeded"; 
}

This prints custom error messages straight from SQLite.

Alternatively, we can catch exceptions in a try/catch block:

try {

  $sql = "INSERT INTO users (name) VALUES ('Tom')";
  $db->exec($sql);

} catch (PDOException $e) {
  
  echo "Insert failed: " . $e->getMessage();

}

Either method allows handling issues smoothly when they crop up.

Robust error handling ensures your app fails gracefully, and helps track down bugs during development.

Putting It All Together – SQLite with PHP

We’ve covered a lot of ground here! Let’s recap the key points:

• Connecting to a SQLite database is as easy as passing the filename
• Creating tables with different field types to model data
• Inserting rows by passing SQL INSERT statements
• Querying data using SELECT and displaying results
• Using transactions to maintain consistency
• Preparing queries for security and reusability
• Error handling to fail gracefully

With these building blocks, you can start developing fully-featured web apps backed by SQLite databases.

By integrating the simplicity of SQLite and power of PHP, you get rock-solid data storage combined with dynamic scripting capabilities… Perfect for rapid web development!

The basic concepts we’ve covered will applies to more complex projects too. I hope this guide has helped demystify working with SQLite and PHP.

There’s so much more we could dig into, but this should kickstart your learning journey. The only limits now are your imagination – go forth and build something awesome!