diff --git a/phpstan.neon b/phpstan.neon
index e697482b..62ab5d12 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -2,7 +2,7 @@ includes:
     - phpstan-baseline.neon
 
 parameters:
-    level: 7
+    level: 8
     paths:
         - src
         - tests
diff --git a/src/Connection.php b/src/Connection.php
index 0035bc12..520f2cca 100755
--- a/src/Connection.php
+++ b/src/Connection.php
@@ -72,7 +72,7 @@ class Connection implements ConnectionInterface
     /**
      * Instance of the db-driver defined in the configs.
      */
-    protected ?DriverInterface $dbDriver = null;
+    protected DriverInterface $dbDriver;
 
     /**
      * The number of transactions currently opened.
@@ -120,7 +120,7 @@ public function close(): void
             $this->logger?->warning('Rolled back open transactions on deletion of current instance of Db!');
         }
 
-        if ($this->dbDriver !== null && $this->connected) {
+        if ($this->connected) {
             $this->logger?->info('closing database-connection');
 
             $this->dbDriver->dbclose();
@@ -216,7 +216,7 @@ public function selectRow(
             ),
         );
 
-        $row = $this->getPRow($query, array_values($identifiers), 0, $cached, $escapes);
+        $row = $this->getPRow($query, array_values($identifiers), 0, $cached, $escapes ?? []);
         if ($row === []) {
             return null;
         }
@@ -317,17 +317,15 @@ public function _pQuery(string $query, array $params = [], array $escapes = []):
         // Increasing the counter
         $this->number++;
 
-        if ($this->dbDriver !== null) {
-            try {
-                $output = $this->dbDriver->_pQuery($query, $this->dbsafeParams($params, $escapes));
-            } catch (QueryException $e) {
-                $prettifiedQuery = $this->prettifyQuery($e->getQuery(), $e->getParams());
+        try {
+            $output = $this->dbDriver->_pQuery($query, $this->dbsafeParams($params, $escapes));
+        } catch (QueryException $e) {
+            $prettifiedQuery = $this->prettifyQuery($e->getQuery(), $e->getParams());
 
-                $this->logger->error($e->getMessage());
-                $this->logger->error('Query: ' . $prettifiedQuery);
+            $this->logger?->error($e->getMessage());
+            $this->logger?->error('Query: ' . $prettifiedQuery);
 
-                throw $e;
-            }
+            throw $e;
         }
 
         if (!$output) {
@@ -618,10 +616,7 @@ private function getError(string $query, array $params): void
             $this->dbconnect();
         }
 
-        $error = '';
-        if ($this->dbDriver !== null) {
-            $error = $this->dbDriver->getError();
-        }
+        $error = $this->dbDriver->getError();
 
         // reprocess query
         $query = str_ireplace(
@@ -665,10 +660,6 @@ public function beginTransaction(): void
             $this->dbconnect();
         }
 
-        if ($this->dbDriver === null) {
-            return;
-        }
-
         // just start a new transaction, if no other transaction is open.
         if ($this->numberOfOpenTransactions === 0) {
             $this->dbDriver->beginTransaction();
@@ -700,10 +691,6 @@ public function commit(): void
             $this->dbconnect();
         }
 
-        if ($this->dbDriver === null) {
-            return;
-        }
-
         // check, if the current tx is allowed to be committed.
         if ($this->numberOfOpenTransactions === 1) {
             $this->numberOfOpenTransactions--;
@@ -743,10 +730,6 @@ public function rollBack(): void
             $this->dbconnect();
         }
 
-        if ($this->dbDriver === null) {
-            return;
-        }
-
         if ($this->numberOfOpenTransactions === 1) {
             $this->dbDriver->rollBack();
             $this->currentTransactionIsDirty = false;
@@ -802,15 +785,13 @@ public function getTables(?string $prefix = null): array
 
         $this->tablesCache[$prefix] = [];
 
-        if ($this->dbDriver !== null) {
-            // increase global counter
-            $this->number++;
-            $tables = $this->dbDriver->getTables();
+        // increase global counter
+        $this->number++;
+        $tables = $this->dbDriver->getTables();
 
-            foreach ($tables as $table) {
-                if (str_starts_with((string) $table['name'], $prefix)) {
-                    $this->tablesCache[$prefix][] = $table['name'];
-                }
+        foreach ($tables as $table) {
+            if (str_starts_with((string) $table['name'], $prefix)) {
+                $this->tablesCache[$prefix][] = $table['name'];
             }
         }
 
@@ -845,7 +826,7 @@ public function getColumnsOfTable(string $tableName): array
             $columnName = $column->getName();
             $return[$columnName] = [
                 'columnName' => $columnName,
-                'columnType' => $column->getInternalType(),
+                'columnType' => $column->getInternalType() ?? DataType::CHAR254,
             ];
         }
 
@@ -949,7 +930,7 @@ public function generateTableFromMetadata(Table $table): void
     {
         $columns = [];
         foreach ($table->getColumns() as $colDef) {
-            $columns[$colDef->getName()] = [$colDef->getInternalType(), $colDef->isNullable()];
+            $columns[$colDef->getName()] = [$colDef->getInternalType() ?? DataType::CHAR254, $colDef->isNullable()];
         }
 
         $primary = [];
@@ -1195,10 +1176,6 @@ public function getDbInfo(): array
             $this->dbconnect();
         }
 
-        if ($this->dbDriver === null) {
-            return [];
-        }
-
         return $this->dbDriver->getDbInfo();
     }
 
diff --git a/src/Driver/DriverAbstract.php b/src/Driver/DriverAbstract.php
index 0a246e17..2f24509a 100644
--- a/src/Driver/DriverAbstract.php
+++ b/src/Driver/DriverAbstract.php
@@ -38,6 +38,9 @@ abstract class DriverAbstract implements DriverInterface
 
     protected ?ConnectionParameters $config = null;
 
+    /**
+     * @phpstan-assert ConnectionParameters $this->config
+     */
     public function setConfig(ConnectionParameters $params): void
     {
         $this->config = $params;
diff --git a/src/Driver/MysqliDriver.php b/src/Driver/MysqliDriver.php
index 7e1c56e1..1775c9eb 100755
--- a/src/Driver/MysqliDriver.php
+++ b/src/Driver/MysqliDriver.php
@@ -27,6 +27,7 @@
 use mysqli_sql_exception;
 use mysqli_stmt;
 use Override;
+use RuntimeException;
 use Symfony\Component\Process\ExecutableFinder;
 use Symfony\Component\Process\Process;
 
@@ -98,6 +99,8 @@ public function dbclose(): void
             return;
         }
 
+        $this->assertConnected();
+
         $this->linkDB->close();
         $this->linkDB = null;
         $this->connected = false;
@@ -237,6 +240,8 @@ public function insertOrUpdate(string $table, array $columns, array $values, arr
     #[Override]
     public function getError(): string
     {
+        $this->assertConnected();
+
         $error = $this->errorMessage . ' ' . $this->linkDB->error;
         $this->errorMessage = '';
 
@@ -274,7 +279,7 @@ public function getTableInformation(string $tableName): Table
             $table->addColumn(
                 TableColumn::make($column['Field'])
                     ->setInternalType($this->getCoreTypeForDbType($column))
-                    ->setDatabaseType($this->getDatatype($this->getCoreTypeForDbType($column)))
+                    ->setDatabaseType($this->getDatatype($this->getCoreTypeForDbType($column) ?? DataType::CHAR254))
                     ->setNullable($column['Null'] === 'YES'),
             );
         }
@@ -454,6 +459,8 @@ public function deleteIndex(string $table, string $index): bool
     #[Override]
     public function beginTransaction(): void
     {
+        $this->assertConnected();
+
         $this->linkDB->begin_transaction();
     }
 
@@ -472,6 +479,8 @@ public function transactionBegin(): void
     #[Override]
     public function commit(): void
     {
+        $this->assertConnected();
+
         $this->linkDB->commit();
     }
 
@@ -487,6 +496,8 @@ public function transactionCommit(): void
     #[Override]
     public function rollBack(): void
     {
+        $this->assertConnected();
+
         $this->linkDB->rollback();
     }
 
@@ -505,6 +516,8 @@ public function transactionRollback(): void
     #[Override]
     public function getDbInfo(): array
     {
+        $this->assertConnected();
+
         return [
             'dbbserver' => 'MySQL ' . $this->linkDB->server_info,
             'server_version' => $this->linkDB->server_version,
@@ -542,6 +555,10 @@ public function encloseTableName(string $table): string
     #[Override]
     public function dbExport(string &$fileName, array $tables): bool
     {
+        if (!$this->config instanceof ConnectionParameters) {
+            throw new RuntimeException('Connection parameters not set');
+        }
+
         $dumpBin = new ExecutableFinder()->find($this->dumpBin);
         $dumpParams = [
             $dumpBin,
@@ -578,7 +595,11 @@ public function dbExport(string &$fileName, array $tables): bool
     public function dbImport(string $fileName): bool
     {
         if (!in_array(pathinfo($fileName, PATHINFO_EXTENSION), ['sql', 'gz'])) {
-            throw new \RuntimeException(trim($fileName . ' is not a valid import file'));
+            throw new RuntimeException(trim($fileName . ' is not a valid import file'));
+        }
+
+        if (!$this->config instanceof ConnectionParameters) {
+            throw new RuntimeException('Connection parameters not set');
         }
 
         $restoreBin = new ExecutableFinder()->find($this->restoreBin);
@@ -598,7 +619,7 @@ public function dbImport(string $fileName): bool
         } elseif (pathinfo($fileName, PATHINFO_EXTENSION) === 'sql') {
             $fileCommand = sprintf('cat %s', escapeshellarg($fileName));
         } else {
-            throw new \RuntimeException(trim($fileName . ' is not a valid import file'));
+            throw new RuntimeException(trim($fileName . ' is not a valid import file'));
         }
 
         $process = new Process([
@@ -636,6 +657,8 @@ private function getPreparedStatement(string $query): false | mysqli_stmt
             $this->statementsCache = [];
         }
 
+        $this->assertConnected();
+
         $statement = $this->linkDB->stmt_init();
 
         try {
@@ -677,4 +700,14 @@ public function getNthLastElementFromSlug(string $column, int $position): string
     {
         return "SUBSTRING_INDEX(SUBSTRING_INDEX($column, '/', -$position), '/', 1)";
     }
+
+    /**
+     * @phpstan-assert mysqli $this->linkDB
+     */
+    private function assertConnected(): void
+    {
+        if ($this->linkDB === null) {
+            throw new ConnectionException('Database not connected.');
+        }
+    }
 }
diff --git a/src/Driver/PostgresDriver.php b/src/Driver/PostgresDriver.php
index 1c985f75..bbf163b8 100755
--- a/src/Driver/PostgresDriver.php
+++ b/src/Driver/PostgresDriver.php
@@ -236,7 +236,7 @@ public function getTableInformation(string $tableName): Table
             $table->addColumn(
                 TableColumn::make($column['column_name'])
                     ->setInternalType($this->getCoreTypeForDbType($column))
-                    ->setDatabaseType($this->getDatatype($this->getCoreTypeForDbType($column)))
+                    ->setDatabaseType($this->getDatatype($this->getCoreTypeForDbType($column) ?? DataType::CHAR254))
                     ->setNullable($column['is_nullable'] === 'YES'),
             );
         }
@@ -510,6 +510,10 @@ public function dbExport(string &$fileName, array $tables): bool
             $tablesString = '-t ' . implode(' -t ', array_map('escapeshellarg', $tables));
         }
 
+        if (!$this->config instanceof ConnectionParameters) {
+            throw new RuntimeException('Connection parameters not set');
+        }
+
         $port = $this->config->getPort();
         if (empty($port)) {
             $port = 5432;
@@ -557,6 +561,10 @@ public function dbImport(string $fileName): bool
             throw new RuntimeException(trim($fileName . ' is not a valid import file'));
         }
 
+        if (!$this->config instanceof ConnectionParameters) {
+            throw new RuntimeException('Connection parameters not set');
+        }
+
         $restoreBin = new ExecutableFinder()->find($this->restoreBin);
         if ($this->handlesDumpCompression() && pathinfo($fileName, PATHINFO_EXTENSION) === 'gz') {
             $restoreParams = [
@@ -618,7 +626,7 @@ protected function processQuery(string $query): string
             $i++;
 
             return '$' . $i;
-        }, $query);
+        }, $query) ?? '';
 
         return str_replace(' LIKE ', ' ILIKE ', $query);
     }
diff --git a/src/Driver/Sqlite3Driver.php b/src/Driver/Sqlite3Driver.php
index 3e18bcc2..44662b94 100755
--- a/src/Driver/Sqlite3Driver.php
+++ b/src/Driver/Sqlite3Driver.php
@@ -306,6 +306,8 @@ public function _pQuery(string $query, array $params): bool
             throw new QueryException('Could not execute statement: ' . $this->getError(), $query, $params);
         }
 
+        $this->assertConnected();
+
         $this->affectedRowsCount = $this->linkDB->changes();
 
         return true;
@@ -351,6 +353,8 @@ public function getPArray(string $query, array $params): Generator
     #[Override]
     public function getError(): string
     {
+        $this->assertConnected();
+
         return $this->linkDB->lastErrorMsg();
     }
 
@@ -385,7 +389,7 @@ public function getTableInformation(string $tableName): Table
             $table->addColumn(
                 TableColumn::make($column['name'])
                     ->setInternalType($this->getCoreTypeForDbType($column))
-                    ->setDatabaseType($this->getDatatype($this->getCoreTypeForDbType($column)))
+                    ->setDatabaseType($this->getDatatype($this->getCoreTypeForDbType($column) ?? DataType::CHAR254))
                     ->setNullable($column['notnull'] == 0),
             );
 
@@ -543,6 +547,8 @@ public function transactionRollback(): void
     #[Override]
     public function getDbInfo(): array
     {
+        $this->assertConnected();
+
         $timeout = iterator_to_array($this->getPArray('PRAGMA busy_timeout', []), false);
         $encoding = iterator_to_array($this->getPArray('PRAGMA encoding', []), false);
 
@@ -615,7 +621,7 @@ private function processQuery(string $query): string
             $i++;
 
             return ':param' . $i;
-        }, $query);
+        }, $query) ?? '';
     }
 
     /**
@@ -629,6 +635,8 @@ private function getPreparedStatement(string $query): false | SQLite3Stmt
             return $this->statementsCache[$name];
         }
 
+        $this->assertConnected();
+
         $statement = $this->linkDB->prepare($query);
         $this->statementsCache[$name] = $statement;
 
@@ -689,4 +697,14 @@ public function getNthLastElementFromSlug(string $column, int $position): string
     {
         return "extract_nth_last_slug_segment($column, $position)";
     }
+
+    /**
+     * @phpstan-assert SQLite3 $this->linkDB
+     */
+    private function assertConnected(): void
+    {
+        if (!$this->linkDB instanceof SQLite3) {
+            throw new ConnectionException('Database not connected.');
+        }
+    }
 }