fix: add SQLite schema versioning for future migrations

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
 

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 = """

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 (