diff --git a/src/ConnectionConfig.php b/src/ConnectionConfig.php
index 58d7db6..2df2f9f 100644
--- a/src/ConnectionConfig.php
+++ b/src/ConnectionConfig.php
@@ -2,7 +2,146 @@
 
 namespace Amp\Sql;
 
-interface ConnectionConfig
+abstract class ConnectionConfig
 {
-    public function connectionString(): string;
+    /** @var string */
+    private $host;
+
+    /** @var int */
+    private $port;
+
+    /** @var string|null */
+    private $user;
+
+    /** @var string|null */
+    private $password;
+
+    /** @var string|null */
+    private $database;
+
+    /**
+     * Parses a connection string into an array of keys and values given.
+     *
+     * @param string $connectionString
+     *
+     * @return array
+     */
+    protected static function parseConnectionString(string $connectionString): array
+    {
+        $values = [];
+
+        $params = \explode(";", $connectionString);
+
+        if (\count($params) === 1) { // Attempt to explode on a space if no ';' are found.
+            $params = \explode(" ", $connectionString);
+        }
+
+        foreach ($params as $param) {
+            list($key, $value) = \array_map("trim", \explode("=", $param, 2) + [1 => null]);
+            $values[$key] = $value;
+        }
+
+        return $values;
+    }
+
+    public function __construct(string $host, int $port, string $user = null, string $password = null, string $database = null)
+    {
+        $this->host = $host;
+        $this->port = $port;
+        $this->user = $user;
+        $this->password = $password;
+        $this->database = $database;
+    }
+
+    public function getConnectionString(): string
+    {
+        $chunks = [
+            "host=" . $this->host,
+            "port=" . $this->port,
+        ];
+
+        if ($this->user !== null) {
+            $chunks[] = "user=" . $this->user;
+        }
+
+        if ($this->password !== null) {
+            $chunks[] = "password=" . $this->password;
+        }
+
+        if ($this->database !== null) {
+            $chunks[] = "db=" . $this->database;
+        }
+
+        return \implode(" ", $chunks);
+    }
+
+    final public function getHost(): string
+    {
+        return $this->host;
+    }
+
+    final public function withHost(string $host): self
+    {
+        $new = clone $this;
+        $new->host = $host;
+        return $new;
+    }
+
+    final public function getPort(): int
+    {
+        return $this->port;
+    }
+
+    final public function withPort(int $port): self
+    {
+        $new = clone $this;
+        $new->port = $port;
+        return $new;
+    }
+
+    /**
+     * @return string|null
+     */
+    final public function getUser() /* : ?string */
+    {
+        return $this->user;
+    }
+
+    final public function withUser(string $user = null): self
+    {
+        $new = clone $this;
+        $new->user = $user;
+        return $new;
+    }
+
+    /**
+     * @return string|null
+     */
+    final public function getPassword() /* : ?string */
+    {
+        return $this->password;
+    }
+
+    final public function withPassword(string $password = null): self
+    {
+        $new = clone $this;
+        $new->password = $password;
+        return $new;
+    }
+
+    /**
+     * @return string|null
+     */
+    final public function getDatabase() /* : ?string */
+    {
+        return $this->database;
+    }
+
+    final public function withDatabase(string $database = null): self
+    {
+        $new = clone $this;
+        $new->database = $database;
+        return $new;
+    }
+
 }