diff --git a/core/_install.php b/core/_install.php
index dcc622be..99fa864d 100644
--- a/core/_install.php
+++ b/core/_install.php
@@ -110,7 +110,7 @@ function do_install()
 { // {{{
     if (file_exists("data/config/auto_install.conf.php")) {
         require_once "data/config/auto_install.conf.php";
-    } elseif (@$_POST["database_type"] == "sqlite") {
+    } elseif (@$_POST["database_type"] == Database::SQLITE_DRIVER) {
         $id = bin2hex(random_bytes(5));
         define('DATABASE_DSN', "sqlite:data/shimmie.{$id}.sqlite");
     } elseif (isset($_POST['database_type']) && isset($_POST['database_host']) && isset($_POST['database_user']) && isset($_POST['database_name'])) {
@@ -153,9 +153,9 @@ function ask_questions()
 
     $drivers = PDO::getAvailableDrivers();
     if (
-        !in_array("mysql", $drivers) &&
-        !in_array("pgsql", $drivers) &&
-        !in_array("sqlite", $drivers)
+        !in_array(Database::MYSQL_DRIVER, $drivers) &&
+        !in_array(Database::PGSQL_DRIVER, $drivers) &&
+        !in_array(Database::SQLITE_DRIVER, $drivers)
     ) {
         $errors[] = "
 			No database connection library could be found; shimmie needs
@@ -163,9 +163,9 @@ function ask_questions()
 		";
     }
 
-    $db_m = in_array("mysql", $drivers)  ? '<option value="mysql">MySQL</option>' : "";
-    $db_p = in_array("pgsql", $drivers)  ? '<option value="pgsql">PostgreSQL</option>' : "";
-    $db_s = in_array("sqlite", $drivers) ? '<option value="sqlite">SQLite</option>' : "";
+    $db_m = in_array(Database::MYSQL_DRIVER, $drivers)  ? '<option value="'.Database::MYSQL_DRIVER.'">MySQL</option>' : "";
+    $db_p = in_array(Database::PGSQL_DRIVER, $drivers)  ? '<option value="'.Database::PGSQL_DRIVER.'">PostgreSQL</option>' : "";
+    $db_s = in_array(Database::SQLITE_DRIVER, $drivers) ? '<option value="'.Database::SQLITE_DRIVER.'">SQLite</option>' : "";
 
     $warn_msg = $warnings ? "<h3>Warnings</h3>".implode("\n<p>", $warnings) : "";
     $err_msg = $errors ? "<h3>Errors</h3>".implode("\n<p>", $errors) : "";
diff --git a/core/database.php b/core/database.php
index c6135878..29381209 100644
--- a/core/database.php
+++ b/core/database.php
@@ -4,6 +4,10 @@
  */
 class Database
 {
+    const MYSQL_DRIVER = "mysql";
+    const PGSQL_DRIVER = "pgsql";
+    const SQLITE_DRIVER = "sqlite";
+
     /**
      * The PDO database connection object, for anyone who wants direct access.
      * @var null|PDO
@@ -72,7 +76,7 @@ class Database
 
         // https://bugs.php.net/bug.php?id=70221
         $ka = DATABASE_KA;
-        if (version_compare(PHP_VERSION, "6.9.9") == 1 && $this->get_driver_name() == "sqlite") {
+        if (version_compare(PHP_VERSION, "6.9.9") == 1 && $this->get_driver_name() == self::SQLITE_DRIVER) {
             $ka = false;
         }
 
@@ -96,11 +100,11 @@ class Database
             throw new SCoreException("Can't figure out database engine");
         }
 
-        if ($db_proto === "mysql") {
+        if ($db_proto === self::MYSQL_DRIVER) {
             $this->engine = new MySQL();
-        } elseif ($db_proto === "pgsql") {
+        } elseif ($db_proto === self::PGSQL_DRIVER) {
             $this->engine = new PostgreSQL();
-        } elseif ($db_proto === "sqlite") {
+        } elseif ($db_proto === self::SQLITE_DRIVER) {
             $this->engine = new SQLite();
         } else {
             die('Unknown PDO driver: '.$db_proto);
@@ -224,7 +228,7 @@ class Database
             }
             return $stmt;
         } catch (PDOException $pdoe) {
-            throw new SCoreException($pdoe->getMessage()."<p><b>Query:</b> ".$query);
+            throw new SCoreException($pdoe->getMessage()."<p><b>Query:</b> ".$query, $pdoe->getCode(), $pdoe);
         }
     }
 
@@ -296,7 +300,7 @@ class Database
      */
     public function get_last_insert_id(string $seq): int
     {
-        if ($this->engine->name == "pgsql") {
+        if ($this->engine->name == self::PGSQL_DRIVER) {
             return $this->db->lastInsertId($seq);
         } else {
             return $this->db->lastInsertId();
@@ -326,15 +330,15 @@ class Database
             $this->connect_db();
         }
 
-        if ($this->engine->name === "mysql") {
+        if ($this->engine->name === self::MYSQL_DRIVER) {
             return count(
                 $this->get_all("SHOW TABLES")
             );
-        } elseif ($this->engine->name === "pgsql") {
+        } elseif ($this->engine->name === self::PGSQL_DRIVER) {
             return count(
                 $this->get_all("SELECT table_name FROM information_schema.tables WHERE table_schema = 'public'")
             );
-        } elseif ($this->engine->name === "sqlite") {
+        } elseif ($this->engine->name === self::SQLITE_DRIVER) {
             return count(
                 $this->get_all("SELECT name FROM sqlite_master WHERE type = 'table'")
             );
diff --git a/core/dbengine.php b/core/dbengine.php
index bb7c674b..d76a1a43 100644
--- a/core/dbengine.php
+++ b/core/dbengine.php
@@ -22,7 +22,7 @@ class DBEngine
 class MySQL extends DBEngine
 {
     /** @var string */
-    public $name = "mysql";
+    public $name = Database::MYSQL_DRIVER;
 
     public function init(PDO $db)
     {
@@ -54,7 +54,7 @@ class MySQL extends DBEngine
 class PostgreSQL extends DBEngine
 {
     /** @var string */
-    public $name = "pgsql";
+    public $name = Database::PGSQL_DRIVER;
 
     public function init(PDO $db)
     {
@@ -136,7 +136,7 @@ function _ln($n)
 class SQLite extends DBEngine
 {
     /** @var string  */
-    public $name = "sqlite";
+    public $name = Database::SQLITE_DRIVER;
 
     public function init(PDO $db)
     {
diff --git a/core/imageboard/image.php b/core/imageboard/image.php
index 928d4914..af6a15d8 100644
--- a/core/imageboard/image.php
+++ b/core/imageboard/image.php
@@ -590,7 +590,7 @@ class Image
     public function delete_tags_from_image(): void
     {
         global $database;
-        if ($database->get_driver_name() == "mysql") {
+        if ($database->get_driver_name() == Database::MYSQL_DRIVER) {
             //mysql < 5.6 has terrible subquery optimization, using EXISTS / JOIN fixes this
             $database->execute(
                 "
@@ -907,7 +907,7 @@ class Image
 
         // more than one positive tag, or more than zero negative tags
         else {
-            if ($database->get_driver_name() === "mysql") {
+            if ($database->get_driver_name() === Database::MYSQL_DRIVER) {
                 $query = Image::build_ugly_search_querylet($tag_querylets);
             } else {
                 $query = Image::build_accurate_search_querylet($tag_querylets);
diff --git a/core/user.php b/core/user.php
index 098c7723..a2a4d537 100644
--- a/core/user.php
+++ b/core/user.php
@@ -69,7 +69,7 @@ class User
         global $config, $database;
         $row = $database->cache->get("user-session:$name-$session");
         if (!$row) {
-            if ($database->get_driver_name() === "mysql") {
+            if ($database->get_driver_name() === Database::MYSQL_DRIVER) {
                 $query = "SELECT * FROM users WHERE name = :name AND md5(concat(pass, :ip)) = :sess";
             } else {
                 $query = "SELECT * FROM users WHERE name = :name AND md5(pass || :ip) = :sess";
diff --git a/ext/admin/main.php b/ext/admin/main.php
index 212b07fb..2b484bc1 100644
--- a/ext/admin/main.php
+++ b/ext/admin/main.php
@@ -201,14 +201,14 @@ class AdminPage extends Extension
         $database = $matches['dbname'];
 
         switch ($software) {
-            case 'mysql':
+            case Database::MYSQL_DRIVER:
                 $cmd = "mysqldump -h$hostname -u$username -p$password $database";
                 break;
-            case 'pgsql':
+            case Database::PGSQL_DRIVER:
                 putenv("PGPASSWORD=$password");
                 $cmd = "pg_dump -h $hostname -U $username $database";
                 break;
-            case 'sqlite':
+            case Database::SQLITE_DRIVER:
                 $cmd = "sqlite3 $database .dump";
                 break;
             default:
@@ -257,7 +257,7 @@ class AdminPage extends Extension
         //TODO: Update score_log (Having an optional ID column for score_log would be nice..)
         preg_match("#^(?P<proto>\w+)\:(?:user=(?P<user>\w+)(?:;|$)|password=(?P<password>\w*)(?:;|$)|host=(?P<host>[\w\.\-]+)(?:;|$)|dbname=(?P<dbname>[\w_]+)(?:;|$))+#", DATABASE_DSN, $matches);
 
-        if ($matches['proto'] == "mysql") {
+        if ($matches['proto'] == Database::MYSQL_DRIVER) {
             $tables = $database->get_col("SELECT TABLE_NAME
 			                              FROM information_schema.KEY_COLUMN_USAGE
 			                              WHERE TABLE_SCHEMA = :db
@@ -280,9 +280,9 @@ class AdminPage extends Extension
                 $i++;
             }
             $database->execute("ALTER TABLE images AUTO_INCREMENT=".(count($ids) + 1));
-        } elseif ($matches['proto'] == "pgsql") {
+        } elseif ($matches['proto'] == Database::PGSQL_DRIVER) {
             //TODO: Make this work with PostgreSQL
-        } elseif ($matches['proto'] == "sqlite") {
+        } elseif ($matches['proto'] == Database::SQLITE_DRIVER) {
             //TODO: Make this work with SQLite
         }
         return true;
diff --git a/ext/admin/theme.php b/ext/admin/theme.php
index 3e60d224..5d3de30f 100644
--- a/ext/admin/theme.php
+++ b/ext/admin/theme.php
@@ -45,7 +45,7 @@ class AdminPageTheme extends Themelet
             $html .= $this->button("Download all images", "download_all_images", false);
         }
         $html .= $this->button("Download database contents", "database_dump", false);
-        if ($database->get_driver_name() == "mysql") {
+        if ($database->get_driver_name() == Database::MYSQL_DRIVER) {
             $html .= $this->button("Reset image IDs", "reset_image_ids", true);
         }
         $page->add_block(new Block("Misc Admin Tools", $html));
diff --git a/ext/comment/main.php b/ext/comment/main.php
index 85a9672b..75b171d4 100644
--- a/ext/comment/main.php
+++ b/ext/comment/main.php
@@ -480,14 +480,14 @@ class CommentList extends Extension
         global $config, $database;
 
         // sqlite fails at intervals
-        if ($database->get_driver_name() === "sqlite") {
+        if ($database->get_driver_name() === Database::SQLITE_DRIVER) {
             return false;
         }
 
         $window = int_escape($config->get_int('comment_window'));
         $max = int_escape($config->get_int('comment_limit'));
 
-        if ($database->get_driver_name() == "mysql") {
+        if ($database->get_driver_name() == Database::MYSQL_DRIVER) {
             $window_sql = "interval $window minute";
         } else {
             $window_sql = "interval '$window minute'";
diff --git a/ext/index/test.php b/ext/index/test.php
index e9debe74..8f57bdb2 100644
--- a/ext/index/test.php
+++ b/ext/index/test.php
@@ -157,7 +157,7 @@ class IndexTest extends ShimmiePHPUnitTestCase
 
         global $database;
         $db = $database->get_driver_name();
-        if ($db == "pgsql" || $db == "sqlite") {
+        if ($db == Database::PGSQL_DRIVER || $db == Database::SQLITE_DRIVER) {
             $this->markTestIncomplete();
         }
 
diff --git a/ext/ipban/main.php b/ext/ipban/main.php
index 659246f9..541c853b 100644
--- a/ext/ipban/main.php
+++ b/ext/ipban/main.php
@@ -235,7 +235,7 @@ class IPBan extends Extension
     {
         global $config, $database;
 
-        $prefix = ($database->get_driver_name() == "sqlite" ? "bans." : "");
+        $prefix = ($database->get_driver_name() == Database::SQLITE_DRIVER ? "bans." : "");
 
         $bans = $this->get_active_bans();
 
diff --git a/ext/ipban/theme.php b/ext/ipban/theme.php
index 6529c51f..67979128 100644
--- a/ext/ipban/theme.php
+++ b/ext/ipban/theme.php
@@ -16,7 +16,7 @@ class IPBanTheme extends Themelet
     {
         global $database, $user;
         $h_bans = "";
-        $prefix = ($database->get_driver_name() == "sqlite" ? "bans." : "");
+        $prefix = ($database->get_driver_name() == Database::SQLITE_DRIVER ? "bans." : "");
         foreach ($bans as $ban) {
             $end_human = date('Y-m-d', $ban[$prefix.'end_timestamp']);
             $h_bans .= "
diff --git a/ext/log_db/main.php b/ext/log_db/main.php
index b185c783..5b400b12 100644
--- a/ext/log_db/main.php
+++ b/ext/log_db/main.php
@@ -68,7 +68,7 @@ class LogDatabase extends Extension
                     $args["module"] = $_GET["module"];
                 }
                 if (!empty($_GET["user"])) {
-                    if ($database->get_driver_name() == "pgsql") {
+                    if ($database->get_driver_name() == Database::PGSQL_DRIVER) {
                         if (preg_match("#\d+\.\d+\.\d+\.\d+(/\d+)?#", $_GET["user"])) {
                             $wheres[] = "(username = :user1 OR text(address) = :user2)";
                             $args["user1"] = $_GET["user"];
diff --git a/ext/rating/main.php b/ext/rating/main.php
index 18b40823..9f32280d 100644
--- a/ext/rating/main.php
+++ b/ext/rating/main.php
@@ -37,7 +37,7 @@ class RatingSetEvent extends Event
 
 class Ratings extends Extension
 {
-    protected $db_support = ['mysql','pgsql'];  // ?
+    protected $db_support = [Database::MYSQL_DRIVER,Database::PGSQL_DRIVER];
 
     public function get_priority(): int
     {
@@ -331,10 +331,10 @@ class Ratings extends Extension
         if ($config->get_int("ext_ratings2_version") < 3) {
             $database->Execute("UPDATE images SET rating = 'u' WHERE rating is null");
             switch ($database->get_driver_name()) {
-                case "mysql":
+                case Database::MYSQL_DRIVER:
                     $database->Execute("ALTER TABLE images CHANGE rating rating CHAR(1) NOT NULL DEFAULT 'u'");
                     break;
-                case "pgsql":
+                case Database::PGSQL_DRIVER:
                     $database->Execute("ALTER TABLE images ALTER COLUMN rating SET DEFAULT 'u'");
                     $database->Execute("ALTER TABLE images ALTER COLUMN rating SET NOT NULL");
                     break;
diff --git a/ext/relatationships/main.php b/ext/relatationships/main.php
index 28e785d1..402f4fd0 100644
--- a/ext/relatationships/main.php
+++ b/ext/relatationships/main.php
@@ -8,7 +8,7 @@
 
 class Relationships extends Extension
 {
-    protected $db_support = ['mysql', 'pgsql'];
+    protected $db_support = [Database::MYSQL_DRIVER, Database::PGSQL_DRIVER];
 
     public function onInitExt(InitExtEvent $event)
     {
diff --git a/ext/rss_comments/main.php b/ext/rss_comments/main.php
index 4f3b5ed5..dfc37717 100644
--- a/ext/rss_comments/main.php
+++ b/ext/rss_comments/main.php
@@ -9,7 +9,7 @@
 
 class RSS_Comments extends Extension
 {
-    protected $db_support = ['mysql', 'sqlite'];  // pgsql has no UNIX_TIMESTAMP
+    protected $db_support = [Database::MYSQL_DRIVER, Database::SQLITE_DRIVER];  // pgsql has no UNIX_TIMESTAMP
 
     public function onPostListBuilding(PostListBuildingEvent $event)
     {
diff --git a/ext/rule34/main.php b/ext/rule34/main.php
index a39b6949..577ca5af 100644
--- a/ext/rule34/main.php
+++ b/ext/rule34/main.php
@@ -19,7 +19,7 @@ if ( // kill these glitched requests immediately
 
 class Rule34 extends Extension
 {
-    protected $db_support = ['pgsql'];  # Only PG has the NOTIFY pubsub system
+    protected $db_support = [Database::PGSQL_DRIVER];  # Only PG has the NOTIFY pubsub system
 
     public function onImageDeletion(ImageDeletionEvent $event)
     {
diff --git a/ext/rule34/theme.php b/ext/rule34/theme.php
index 09712b3d..d4dd29e1 100644
--- a/ext/rule34/theme.php
+++ b/ext/rule34/theme.php
@@ -19,7 +19,7 @@ class Rule34Theme extends Themelet
     {
         global $database, $user;
         $h_bans = "";
-        $prefix = ($database->get_driver_name() == "sqlite" ? "bans." : "");
+        $prefix = ($database->get_driver_name() == Database::SQLITE_DRIVER ? "bans." : "");
         foreach ($bans as $ban) {
             $h_bans .= "
 				<tr>
diff --git a/ext/tips/main.php b/ext/tips/main.php
index f4f7d619..04fb5124 100644
--- a/ext/tips/main.php
+++ b/ext/tips/main.php
@@ -10,7 +10,7 @@
 
 class Tips extends Extension
 {
-    protected $db_support = ['mysql', 'sqlite'];  // rand() ?
+    protected $db_support = [Database::MYSQL_DRIVER, Database::SQLITE_DRIVER];  // rand() ?
 
     public function onInitExt(InitExtEvent $event)
     {
diff --git a/ext/upgrade/main.php b/ext/upgrade/main.php
index 3321b409..0aef4530 100644
--- a/ext/upgrade/main.php
+++ b/ext/upgrade/main.php
@@ -44,7 +44,7 @@ class Upgrade extends Extension
             $config->set_bool("in_upgrade", true);
             $config->set_int("db_version", 9);
 
-            if ($database->get_driver_name() == 'mysql') {
+            if ($database->get_driver_name() == Database::MYSQL_DRIVER) {
                 $tables = $database->get_col("SHOW TABLES");
                 foreach ($tables as $table) {
                     log_info("upgrade", "converting $table to innodb");
@@ -84,7 +84,7 @@ class Upgrade extends Extension
             $config->set_bool("in_upgrade", true);
             $config->set_int("db_version", 12);
 
-            if ($database->get_driver_name() == 'pgsql') {
+            if ($database->get_driver_name() == Database::PGSQL_DRIVER) {
                 log_info("upgrade", "Changing ext column to VARCHAR");
                 $database->execute("ALTER TABLE images ALTER COLUMN ext SET DATA TYPE VARCHAR(4)");
             }
@@ -101,9 +101,9 @@ class Upgrade extends Extension
             $config->set_int("db_version", 13);
 
             log_info("upgrade", "Changing password column to VARCHAR(250)");
-            if ($database->get_driver_name() == 'pgsql') {
+            if ($database->get_driver_name() == Database::PGSQL_DRIVER) {
                 $database->execute("ALTER TABLE users ALTER COLUMN pass SET DATA TYPE VARCHAR(250)");
-            } elseif ($database->get_driver_name() == 'mysql') {
+            } elseif ($database->get_driver_name() == Database::MYSQL_DRIVER) {
                 $database->execute("ALTER TABLE users CHANGE pass pass VARCHAR(250)");
             }
 
@@ -116,11 +116,11 @@ class Upgrade extends Extension
             $config->set_int("db_version", 14);
 
             log_info("upgrade", "Changing tag column to VARCHAR(255)");
-            if ($database->get_driver_name() == 'pgsql') {
+            if ($database->get_driver_name() == Database::PGSQL_DRIVER) {
                 $database->execute('ALTER TABLE tags ALTER COLUMN tag SET DATA TYPE VARCHAR(255)');
                 $database->execute('ALTER TABLE aliases ALTER COLUMN oldtag SET DATA TYPE VARCHAR(255)');
                 $database->execute('ALTER TABLE aliases ALTER COLUMN newtag SET DATA TYPE VARCHAR(255)');
-            } elseif ($database->get_driver_name() == 'mysql') {
+            } elseif ($database->get_driver_name() == Database::MYSQL_DRIVER) {
                 $database->execute('ALTER TABLE tags MODIFY COLUMN tag VARCHAR(255) NOT NULL');
                 $database->execute('ALTER TABLE aliases MODIFY COLUMN oldtag VARCHAR(255) NOT NULL');
                 $database->execute('ALTER TABLE aliases MODIFY COLUMN newtag VARCHAR(255) NOT NULL');