From 451f2e0d19ee53da7af5203511027570c02f2d5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ng=C3=B4=20Qu=E1=BB=91c=20=C4=90=E1=BA=A1t?=
 <datlechin@gmail.com>
Date: Mon, 6 Apr 2026 13:03:23 +0700
Subject: [PATCH] fix: add PRAGMA user_version schema migration infrastructure
 to SQLite databases

---
 CHANGELOG.md                                  |  1 +
 .../Core/Storage/QueryHistoryStorage.swift    | 34 +++++++++++++++++++
 .../Core/Storage/SQLFavoriteStorage.swift     | 34 +++++++++++++++++++
 3 files changed, 69 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 14165fc1a..38601ee00 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix crash when closing window during SSH tunnel connection (use-after-free in libssh2)
 - Fix potential deadlock in SSH host key verification prompts (semaphore → async/await)
 - Fix data race in ConnectionStorage, GroupStorage, and TagStorage (added @MainActor isolation)
+- Add schema versioning to SQLite databases (query history, favorites) for future migrations
 
 ### Added
 
diff --git a/TablePro/Core/Storage/QueryHistoryStorage.swift b/TablePro/Core/Storage/QueryHistoryStorage.swift
index 139b4260a..314811e38 100644
--- a/TablePro/Core/Storage/QueryHistoryStorage.swift
+++ b/TablePro/Core/Storage/QueryHistoryStorage.swift
@@ -150,8 +150,42 @@ final class QueryHistoryStorage {
         execute("PRAGMA synchronous=NORMAL;")
 
         createTables()
+        migrateIfNeeded()
     }
 
+    // MARK: - Schema Migration
+
+    private func migrateIfNeeded() {
+        let currentVersion = getUserVersion()
+
+        // Future migrations go here:
+        // if currentVersion < 2 {
+        //     execute("ALTER TABLE history ADD COLUMN new_col TEXT;")
+        // }
+
+        let targetVersion: Int32 = 1
+        if currentVersion < targetVersion {
+            setUserVersion(targetVersion)
+        }
+    }
+
+    private func getUserVersion() -> Int32 {
+        var statement: OpaquePointer?
+        defer { sqlite3_finalize(statement) }
+        guard sqlite3_prepare_v2(db, "PRAGMA user_version", -1, &statement, nil) == SQLITE_OK,
+              sqlite3_step(statement) == SQLITE_ROW
+        else {
+            return 0
+        }
+        return sqlite3_column_int(statement, 0)
+    }
+
+    private func setUserVersion(_ version: Int32) {
+        execute("PRAGMA user_version = \(version);")
+    }
+
+    // MARK: - Table Creation
+
     private func createTables() {
         // History table
         let historyTable = """
diff --git a/TablePro/Core/Storage/SQLFavoriteStorage.swift b/TablePro/Core/Storage/SQLFavoriteStorage.swift
index 174f61231..6becb3ced 100644
--- a/TablePro/Core/Storage/SQLFavoriteStorage.swift
+++ b/TablePro/Core/Storage/SQLFavoriteStorage.swift
@@ -109,8 +109,42 @@ internal final class SQLFavoriteStorage {
         execute("PRAGMA synchronous=NORMAL;")
 
         createTables()
+        migrateIfNeeded()
     }
 
+    // MARK: - Schema Migration
+
+    private func migrateIfNeeded() {
+        let currentVersion = getUserVersion()
+
+        // Future migrations go here:
+        // if currentVersion < 2 {
+        //     execute("ALTER TABLE favorites ADD COLUMN new_col TEXT;")
+        // }
+
+        let targetVersion: Int32 = 1
+        if currentVersion < targetVersion {
+            setUserVersion(targetVersion)
+        }
+    }
+
+    private func getUserVersion() -> Int32 {
+        var statement: OpaquePointer?
+        defer { sqlite3_finalize(statement) }
+        guard sqlite3_prepare_v2(db, "PRAGMA user_version", -1, &statement, nil) == SQLITE_OK,
+              sqlite3_step(statement) == SQLITE_ROW
+        else {
+            return 0
+        }
+        return sqlite3_column_int(statement, 0)
+    }
+
+    private func setUserVersion(_ version: Int32) {
+        execute("PRAGMA user_version = \(version);")
+    }
+
+    // MARK: - Table Creation
+
     private func createTables() {
         let favoritesTable = """
             CREATE TABLE IF NOT EXISTS favorites (