diff --git a/PHPCI/Builder.php b/PHPCI/Builder.php
index 5a26be8d..a7b60bc1 100644
--- a/PHPCI/Builder.php
+++ b/PHPCI/Builder.php
@@ -73,6 +73,15 @@ class Builder
     * @var array
     */
     protected $config;
+    
+    /**
+     * An array of key => value pairs that will be used for 
+     * interpolation and environment variables
+     * @var array
+     * @see setInterpolationVars()
+     * @see getInterpolationVars()
+     */
+    protected $interpolation_vars = array();
 
     /**
     * Set up the builder.
@@ -236,7 +245,47 @@ class Builder
     {
         $this->log("\033[0;31m" . $message . "\033[0m");
     }
+    
+    /**
+     * Get an array key => value pairs that are used for interpolation
+     * @return array
+     */
+    public function getInterpolationVars()
+    {
+        return $this->interpolation_vars;
+    }
+    
+    /**
+     * Replace every occurance of the interpolation vars in the given string
+     * Example: "This is build %PHPCI_BUILD%" => "This is build 182"
+     * @param string $input
+     * @return string
+     */
+    public function interpolate($input)
+    {
+        $trans_table = array();
+        foreach ($this->getInterpolationVars() as $key => $value) {
+            $trans_table['%'.$key.'%'] = $value;
+        }
+        return strtr($input, $trans_table);
+    }
 
+    /**
+     * Sets the variables that will be used for interpolation. This must be run 
+     * from setupBuild() because prior to that, we don't know the buildPath
+     */
+    protected function setInterpolationVars()
+    {
+        $this->interpolation_vars = array(
+            'PHPCI'               => 1,
+            'PHPCI_COMMIT'        => $this->build->getCommitId(),
+            'PHPCI_PROJECT'       => $this->build->getProject()->getId(),
+            'PHPCI_BUILD'         => $this->build->getId(),
+            'PHPCI_PROJECT_TITLE' => $this->build->getProject()->getTitle(),
+            'PHPCI_BUILD_PATH'    => $this->buildPath,
+        );
+    }
+    
     /**
     * Set up a working copy of the project for building.
     */
@@ -247,14 +296,13 @@ class Builder
         $this->ciDir        = realpath(dirname(__FILE__) . '/../') . '/';
         $this->buildPath    = $this->ciDir . 'build/' . $buildId . '/';
         
+        $this->setInterpolationVars();
+        
         // Setup environment vars that will be accessible during exec()
-        putenv("PHPCI=1");
-        putenv("PHPCI_COMMIT=".$commitId);
-        putenv("PHPCI_PROJECT=".$this->build->getProject()->getId());
-        putenv("PHPCI_BUILD=".$this->build->getId());
-        putenv("PHPCI_PROJECT_TITLE=".$this->build->getProject()->getTitle());
-        putenv("PHPCI_BUILD_PATH=".$this->buildPath);
-
+        foreach ($this->getInterpolationVars() as $key => $value) {
+            putenv($key.'='.$value);
+        }
+        
         // Create a working copy of the project:
         if (!$this->build->createWorkingCopy($this, $this->buildPath)) {
             return false;
diff --git a/PHPCI/Plugin/Env.php b/PHPCI/Plugin/Env.php
index 1de016fb..e09d3dbf 100644
--- a/PHPCI/Plugin/Env.php
+++ b/PHPCI/Plugin/Env.php
@@ -41,7 +41,7 @@ class Env implements \PHPCI\Plugin
                 $env_var = "$key=$value";
             }
             
-            if (!putenv($env_var)) {
+            if (!putenv($this->phpci->interpolate($env_var))) {
                 $success = false;
                 $this->phpci->logFailure("Unable to set environment variable");
             }
diff --git a/PHPCI/Plugin/Mysql.php b/PHPCI/Plugin/Mysql.php
index e67c31a4..5138116e 100644
--- a/PHPCI/Plugin/Mysql.php
+++ b/PHPCI/Plugin/Mysql.php
@@ -51,8 +51,8 @@ class Mysql implements \PHPCI\Plugin
         if (isset($buildSettings['mysql'])) {
             $sql    = $buildSettings['mysql'];
 
-            $this->host = !empty($sql['host']) ? $sql['host'] : $this->host;
-            $this->user = !empty($sql['user']) ? $sql['user'] : $this->user;
+            $this->host = !empty($sql['host']) ? $sql['host'] : $this->phpci->interpolate($this->host);
+            $this->user = !empty($sql['user']) ? $sql['user'] : $this->phpci->interpolate($this->user);
             $this->pass = array_key_exists('pass', $sql) ? $sql['pass'] : $this->pass;
         }
     }
@@ -71,10 +71,12 @@ class Mysql implements \PHPCI\Plugin
             foreach ($this->queries as $query) {
                 if (!is_array($query)) {
                     // Simple query
-                    $this->pdo->query($query);
+                    $this->pdo->query($this->phpci->interpolate($query));
                 } else if (isset($query['import'])) {
                     // SQL file execution
                     $this->executeFile($query['import']);
+                } else {
+                    throw new \Exception("Invalid command");
                 }
             }
         } catch (\Exception $ex) {
@@ -88,15 +90,15 @@ class Mysql implements \PHPCI\Plugin
     protected function executeFile($query)
     {
         if (!isset($query['file'])) {
-            throw new \Exception("Import statement must contiain an 'file' key");
+            throw new \Exception("Import statement must contain a 'file' key");
         }
         
-        $import_file = $this->phpci->buildPath . $query['file'];
+        $import_file = $this->phpci->buildPath . $this->phpci->interpolate($query['file']);
         if (!is_readable($import_file)) {
         	throw new \Exception("Cannot open SQL import file: $import_file");
         }
         
-        $database = isset($query['database'])? $query['database']: null;
+        $database = isset($query['database'])? $this->phpci->interpolate($query['database']): null;
         
         $import_command = $this->getImportCommand($import_file, $database);
     	if (!$this->phpci->executeCommand($import_command)) {