diff --git a/functions.php b/functions.php
index c9b05216..ff70057d 100644
--- a/functions.php
+++ b/functions.php
@@ -20,7 +20,6 @@ require_once __DIR__ . '/functions/domain.php';
 require_once __DIR__ . '/functions/auth.php';
 require_once __DIR__ . '/functions/logging.php';
 require_once __DIR__ . '/functions/app.php';
-require_once __DIR__ . '/functions/db.php';
 require_once __DIR__ . '/functions/payments.php';
 require_once __DIR__ . '/functions/sla.php';
 require_once __DIR__ . '/functions/export.php';
diff --git a/functions/db.php b/functions/db.php
deleted file mode 100644
index 78ae2d02..00000000
--- a/functions/db.php
+++ /dev/null
@@ -1,224 +0,0 @@
-<?php
-
-// Prepared-statement DB wrapper layer.
-// NOTE: NEW DB LAYER - adoption pending. Not yet called from app code;
-// intended target for the gradual prepared-statement migration. Do not remove.
-// Split from the former monolithic functions.php
-
-
-/**
- * Simple mysqli helper functions
- * - Prepared statements under the hood
- * - "Old style" INSERT/UPDATE SET feeling
- */
-
-/**
- * Core executor: prepares, binds, executes.
- *
- * @throws Exception on error
- */
-function dbExecute(mysqli $mysqli, string $sql, array $params = []): mysqli_stmt
-{
-    $stmt = $mysqli->prepare($sql);
-    if (!$stmt) {
-        throw new Exception('MySQLi prepare error: ' . $mysqli->error . ' | SQL: ' . $sql);
-    }
-
-    if (!empty($params)) {
-        $types  = '';
-        $values = [];
-
-        foreach ($params as $param) {
-            if (is_int($param)) {
-                $types .= 'i';
-            } elseif (is_float($param)) {
-                $types .= 'd';
-            } elseif (is_bool($param)) {
-                $types .= 'i';
-                $param  = $param ? 1 : 0;
-            } elseif (is_null($param)) {
-                $types .= 's';
-                $param  = null;
-            } else {
-                $types .= 's';
-            }
-            $values[] = $param;
-        }
-
-        if (!$stmt->bind_param($types, ...$values)) {
-            throw new Exception('MySQLi bind_param error: ' . $stmt->error . ' | SQL: ' . $sql);
-        }
-    }
-
-    if (!$stmt->execute()) {
-        throw new Exception('MySQLi execute error: ' . $stmt->error . ' | SQL: ' . $sql);
-    }
-
-    return $stmt;
-}
-
-/**
- * Fetch all rows as associative arrays.
- */
-function dbFetchAll(mysqli $mysqli, string $sql, array $params = []): array
-{
-    $stmt   = dbExecute($mysqli, $sql, $params);
-    $result = $stmt->get_result();
-    if ($result === false) {
-        return [];
-    }
-    return $result->fetch_all(MYSQLI_ASSOC);
-}
-
-/**
- * Fetch a single row (assoc) or null if none.
- */
-function dbFetchOne(mysqli $mysqli, string $sql, array $params = []): ?array
-{
-    $stmt   = dbExecute($mysqli, $sql, $params);
-    $result = $stmt->get_result();
-    if ($result === false) {
-        return null;
-    }
-    $row = $result->fetch_assoc();
-    return $row !== null ? $row : null;
-}
-
-/**
- * Fetch a single scalar value (first column of first row) or null.
- */
-function dbFetchValue(mysqli $mysqli, string $sql, array $params = [])
-{
-    $row = dbFetchOne($mysqli, $sql, $params);
-    if ($row === null) {
-        return null;
-    }
-    return reset($row);
-}
-
-/**
- * INSERT using "SET" style.
- * Example:
- *   $id = dbInsert($mysqli, 'clients', [
- *       'client_name' => $name,
- *       'client_type' => $type,
- *   ]);
- *
- * @return int insert_id
- *
- * @throws InvalidArgumentException
- * @throws Exception
- */
-function dbInsert(mysqli $mysqli, string $table, array $data): int
-{
-    if (empty($data)) {
-        throw new InvalidArgumentException('dbInsert called with empty $data');
-    }
-
-    $setParts = [];
-    foreach ($data as $column => $_) {
-        $setParts[] = "$column = ?";
-    }
-
-    $sql    = "INSERT INTO $table SET " . implode(', ', $setParts);
-    $params = array_values($data);
-
-    dbExecute($mysqli, $sql, $params);
-
-    return $mysqli->insert_id;
-}
-
-function dbUpdate(
-    mysqli $mysqli,
-    string $table,
-    array $data,
-    $where,
-    array $whereParams = []
-): int {
-    if (empty($data)) {
-        throw new InvalidArgumentException('dbUpdate called with empty $data');
-    }
-    if (empty($where)) {
-        throw new InvalidArgumentException('dbUpdate requires a WHERE clause');
-    }
-
-    $setParts = [];
-    foreach ($data as $column => $_) {
-        $setParts[] = "$column = ?";
-    }
-
-    if (is_array($where)) {
-        $whereParts  = [];
-        $whereParams = [];
-        foreach ($where as $column => $value) {
-            $whereParts[]  = "$column = ?";
-            $whereParams[] = $value;
-        }
-        $whereSql = implode(' AND ', $whereParts);
-    } else {
-        $whereSql = $where;
-    }
-
-    $sql    = "UPDATE $table SET " . implode(', ', $setParts) . " WHERE $whereSql";
-    $params = array_merge(array_values($data), $whereParams);
-
-    $stmt = dbExecute($mysqli, $sql, $params);
-    return $stmt->affected_rows;
-}
-
-/**
- * DELETE helper.
- *
- * WHERE can be:
- *   - array: ['client_id' => $id] (auto "client_id = ?")
- *   - string: 'client_id = ?' (use with $whereParams)
- *
- * @return int affected_rows
- *
- * @throws InvalidArgumentException
- * @throws Exception
- */
-function dbDelete(
-    mysqli $mysqli,
-    string $table,
-    $where,
-    array $whereParams = []
-): int {
-    if (empty($where)) {
-        throw new InvalidArgumentException('dbDelete requires a WHERE clause');
-    }
-
-    if (is_array($where)) {
-        $whereParts  = [];
-        $whereParams = [];
-        foreach ($where as $column => $value) {
-            $whereParts[]  = "$column = ?";
-            $whereParams[] = $value;
-        }
-        $whereSql = implode(' AND ', $whereParts);
-    } else {
-        $whereSql = $where;
-    }
-
-    $sql  = "DELETE FROM $table WHERE $whereSql";
-    $stmt = dbExecute($mysqli, $sql, $whereParams);
-    return $stmt->affected_rows;
-}
-
-/**
- * Transaction helpers (optional sugar).
- */
-function dbBegin(mysqli $mysqli): void
-{
-    $mysqli->begin_transaction();
-}
-
-function dbCommit(mysqli $mysqli): void
-{
-    $mysqli->commit();
-}
-
-function dbRollback(mysqli $mysqli): void
-{
-    $mysqli->rollback();
-}