# Connecting to PostgreSQL using Perl

> Connect to a PostgreSQL database from a Perl script using the DBI module and the DBD::Pg driver.

Source: https://helpcenter.ruachost.com/developers/databases/connecting-to-postgresql-using-perl/

> **PostgreSQL is available on Managed VPS only:**
Ruachost shared hosting supports MySQL (MariaDB) databases, not PostgreSQL. To use PostgreSQL, choose a [Managed VPS](https://ruachost.com/vps).

Perl provides robust database connectivity through the **DBI (Database Interface)** module and the **DBD::Pg driver** for PostgreSQL. On **ruachost.com**, you can use these modules to connect to PostgreSQL databases, run queries, and manage data directly from your Perl scripts.

## Why Use Perl for PostgreSQL?

- Flexible scripting language for automation and backend tasks.
- DBI provides a consistent interface across multiple databases.
- Supports prepared statements for secure queries.
- Ideal for legacy applications and quick data processing scripts.

## Steps to Connect to PostgreSQL Using Perl

### Step 1: Install Required Modules

1. Log in to your hosting account via SSH.
2. Install the DBI and DBD::Pg modules (if not already available):

   ```bash
   cpan DBI
   cpan DBD::Pg
   ```

   Or, if using `cpanm`:

   ```bash
   cpanm DBI DBD::Pg
   ```

   ```
   ```

### Step 2: Write a Perl Script to Connect

### Example

```
#!/usr/bin/perl
use strict;
use warnings;
use DBI;

# Database connection parameters
my $dbname   = "yourdbname";
my $host     = "localhost";
my $port     = 5432;
my $username = "yourusername";
my $password = "yourpassword";

# Connect to PostgreSQL
my $dbh = DBI->connect("dbi:Pg:dbname=$dbname;host=$host;port=$port",
                       $username, $password,
                       { RaiseError => 1, AutoCommit => 1 })
          or die $DBI::errstr;

print "Connected to PostgreSQL successfully!\n";

# Run a query
my $sth = $dbh->prepare("SELECT fname, lname FROM employee");
$sth->execute();

while (my @row = $sth->fetchrow_array) {
    print "Employee: $row[0] $row[1]\n";
}

# Clean up
$sth->finish();
$dbh->disconnect();
```

### Step 3: Run the Script

- Save the script as `connect_pg.pl`.
- Make it executable:

  ```bash
  chmod +x connect_pg.pl
  ```
- Run the script:

  ```bash
  ./connect_pg.pl
  ```

## Important Notes

- Replace `yourdbname`, `yourusername`, and `yourpassword` with actual database credentials.
- Ensure PostgreSQL is running and accessible from your hosting environment.
- Always close connections (`$dbh->disconnect`) to free resources.
- Use prepared statements to protect against SQL injection.