diff --git a/Makefile b/Makefile
index 3bbe610..74b7b36 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ CC = gcc
 CFLAGS = -Wall -g -std=gnu2x -DMG_TLS=MG_TLS_OPENSSL -ffunction-sections -fdata-sections
 LDFLAGS = -Wl,--gc-sections
 INCLUDES = -I./src/lib -I./src
-SRCS = $(wildcard src/*/*.c src/*.c)
+SRCS = $(wildcard src/lib/*.c src/file_db/*.c src/*.c)
 OBJS = $(SRCS:.c=.o)
 TARGET = auth_service
 BUILD_DIR=./build
@@ -14,6 +14,7 @@ WERROR ?= 0
 ifeq ($(USE_SQLITE3), 1)
 	CFLAGS += -DUSE_SQLITE3
 	LIBS += -lsqlite3
+	SRCS = $(wildcard src/lib/*.c src/sqlite_db/*.c src/file_db/*.c src/*.c)
 endif
 
 ifeq ($(WERROR), 1)
diff --git a/meson.build b/meson.build
index b51d336..277563b 100644
--- a/meson.build
+++ b/meson.build
@@ -7,21 +7,7 @@ extra_c_link_args = ['-Wl,--gc-sections']
 sqlite3_dep = dependency('sqlite3', required: false)
 use_sqlite3 = get_option('use_sqlite3')
 use_werror = get_option('use_werror')
-
-if use_sqlite3
-  if not sqlite3_dep.found()
-    error('SQLite3 requested but not found')
-  endif
-  deps += sqlite3_dep
-  add_project_arguments('-DUSE_SQLITE3', language: 'c')
-endif
-
-if use_werror
-  add_project_arguments('-Werror', language: 'c')
-endif
-
-executable(
-  'auth_service',
+sources = [
   'src/main.c',
   'src/user.c',
   'src/add_user.c',
@@ -52,6 +38,50 @@ executable(
   'src/cors.c',
   'src/db_get_user_field_by_id.c',
   'src/db_update_user_field.c',
+]
+
+with_filedb_sources = [
+  'src/file_db/filedb.c',
+  'src/file_db/filedb_delete_user.c',
+  'src/file_db/filedb_get_all_users.c',
+  'src/file_db/filedb_get_user_by_id.c',
+  'src/file_db/filedb_get_user_by_username.c',
+  'src/file_db/filedb_get_user_field_by_id.c',
+  'src/file_db/filedb_insert_user.c',
+  'src/file_db/filedb_update_user.c',
+  'src/file_db/filedb_update_user_field.c',
+]
+
+with_sqlite3_sources = [
+  'src/sqlite_db/sqlite.c',
+  'src/sqlite_db/sqlite_delete_user.c',
+  'src/sqlite_db/sqlite_get_all_users.c',
+  'src/sqlite_db/sqlite_get_user_by_id.c',
+  'src/sqlite_db/sqlite_get_user_by_username.c',
+  'src/sqlite_db/sqlite_get_user_field_by_id.c',
+  'src/sqlite_db/sqlite_init_db.c',
+  'src/sqlite_db/sqlite_insert_user.c',
+  'src/sqlite_db/sqlite_migrate_db.c',
+  'src/sqlite_db/sqlite_update_user.c',
+  'src/sqlite_db/sqlite_update_user_field.c',
+]
+
+if use_sqlite3
+  if not sqlite3_dep.found()
+    error('SQLite3 requested but not found')
+  endif
+  deps += sqlite3_dep
+  sources += with_sqlite3_sources
+  add_project_arguments('-DUSE_SQLITE3', language: 'c')
+endif
+
+if use_werror
+  add_project_arguments('-Werror', language: 'c')
+endif
+
+executable(
+  'auth_service',
+  sources + with_filedb_sources,
   include_directories: include_dirs,
   dependencies: deps,
   c_args: extra_c_args,
diff --git a/src/database.c b/src/database.c
index 7639e04..cbd371b 100644
--- a/src/database.c
+++ b/src/database.c
@@ -5,25 +5,12 @@
 #include <string.h>
 
 #ifdef USE_SQLITE3
-#include "config.h"
-#include "sql.h"
-#endif
-
-#ifdef USE_SQLITE3
-sqlite3 *db = nullptr;
-pthread_mutex_t db_mutex = PTHREAD_MUTEX_INITIALIZER;
-#else
-pthread_mutex_t users_file_mutex = PTHREAD_MUTEX_INITIALIZER;
+#include "sqlite_db/sqlite.h"
 #endif
 
 void init_db() {
 #ifdef USE_SQLITE3
-  if (sqlite3_open(cm_get_parameter_as_string(config, "database"), &db) !=
-      SQLITE_OK) {
-    fprintf(stderr, "Cannot open database: %s\n", sqlite3_errmsg(db));
-    sqlite3_close(db);
-    exit(1);
-  }
+  sqlite_init_db();
 #else
   return;
 #endif
@@ -31,16 +18,7 @@ void init_db() {
 
 void migrate_db() {
 #ifdef USE_SQLITE3
-  char *err_msg = 0;
-  pthread_mutex_lock(&db_mutex);
-  if (sqlite3_exec(db, CREATE_TABLE_USERS, nullptr, nullptr, &err_msg) !=
-      SQLITE_OK) {
-    fprintf(stderr, "SQL error: %s\n", err_msg);
-    sqlite3_free(err_msg);
-    sqlite3_close(db);
-    exit(1);
-  }
-  pthread_mutex_unlock(&db_mutex);
+  sqlite_migrate_db();
 #else
   return;
 #endif
diff --git a/src/database.h b/src/database.h
index da62dda..0587742 100644
--- a/src/database.h
+++ b/src/database.h
@@ -1,15 +1,5 @@
 #pragma once
 
-#include <pthread.h>
-
-#ifdef USE_SQLITE3
-#include <sqlite3.h>
-extern sqlite3 *db;
-extern pthread_mutex_t db_mutex;
-#else
-extern pthread_mutex_t users_file_mutex;
-#endif
-
 void init_db();
 void migrate_db();
 char *json_escape(const char *str);
diff --git a/src/db_delete_user.c b/src/db_delete_user.c
index 039f997..e0c1820 100644
--- a/src/db_delete_user.c
+++ b/src/db_delete_user.c
@@ -1,79 +1,15 @@
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 bool db_delete_user(const int id) {
 #ifdef USE_SQLITE3
-  pthread_mutex_lock(&db_mutex);
-  if (!db) {
-    fprintf(stderr, "Database not initialized\n");
-    pthread_mutex_unlock(&db_mutex);
-    return false;
-  }
-  sqlite3_stmt *stmt;
-  int rc;
-
-  rc = sqlite3_prepare_v2(db, DELETE_USER_SQL, -1, &stmt, 0);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "Failed to prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return false;
-  }
-
-  sqlite3_bind_int(stmt, 1, id);
-
-  rc = sqlite3_step(stmt);
-  if (rc != SQLITE_DONE) {
-    fprintf(stderr, "Execution failed: %s\n", sqlite3_errmsg(db));
-    sqlite3_finalize(stmt);
-    pthread_mutex_unlock(&db_mutex);
-    return false;
-  }
-
-  int changes = sqlite3_changes(db);
-  sqlite3_finalize(stmt);
-
-  if (changes > 0) {
-    printf("User deleted successfully. ID: %d\n", id);
-  } else {
-    printf("No user found with ID: %d\n", id);
-    pthread_mutex_unlock(&db_mutex);
-    return false;
-  }
-
-  pthread_mutex_unlock(&db_mutex);
-  return true;
+  return sqlite_delete_user(id);
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  cJSON *users = cJSON_Parse(data);
-  cJSON *user = nullptr;
-  int index = 0;
-  bool found = false;
-  cJSON_ArrayForEach(user, users) {
-    cJSON *user_id = cJSON_GetObjectItem(user, "id");
-    if (user_id->valueint == id) {
-      cJSON_DeleteItemFromArray(users, index);
-      found = true;
-      break;
-    }
-    index++;
-  }
-  if (!found) {
-    pthread_mutex_unlock(&users_file_mutex);
-    return false;
-  }
-  char *new_data = cJSON_Print(users);
-  write_file("users_db.json", new_data);
-  free(new_data);
-  free(data);
-  cJSON_Delete(users);
-  pthread_mutex_unlock(&users_file_mutex);
-  return true;
+  return filedb_delete_user(id);
 #endif
 }
diff --git a/src/db_get_all_users.c b/src/db_get_all_users.c
index 2471c96..66763de 100644
--- a/src/db_get_all_users.c
+++ b/src/db_get_all_users.c
@@ -1,110 +1,15 @@
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 char *db_get_all_users() {
 #ifdef USE_SQLITE3
-  pthread_mutex_lock(&db_mutex);
-  if (!db) {
-    fprintf(stderr, "Database not initialized\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  sqlite3_stmt *stmt;
-  int rc;
-
-  rc = sqlite3_prepare_v2(db, SELECT_ALL_USERS_SQL, -1, &stmt, nullptr);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  char *result = malloc(1024);
-  if (!result) {
-    sqlite3_finalize(stmt);
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  strcpy(result, "[");
-  size_t result_size = strlen(result);
-  size_t result_capacity = 1024;
-
-  int first_record = 1;
-
-  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
-    int id = sqlite3_column_int(stmt, 0);
-    const unsigned char *username = sqlite3_column_text(stmt, 1);
-    const unsigned char *email = sqlite3_column_text(stmt, 2);
-    const unsigned char *group = sqlite3_column_text(stmt, 4);
-    int is_superuser = sqlite3_column_int(stmt, 5);
-
-    char *escaped_username = json_escape((const char *) username);
-    char *escaped_email = json_escape((const char *) email);
-    char *escaped_group = json_escape((const char *) group);
-    if (!escaped_username || !escaped_email || !escaped_group) {
-      free(escaped_username);
-      free(escaped_email);
-      free(escaped_group);
-      sqlite3_finalize(stmt);
-      return NULL;
-    }
-
-    char record[512];
-    if (sqlite3_column_type(stmt, 2) == SQLITE_NULL) {
-      snprintf(record, sizeof(record),
-               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
-               "\"%s\",\"is_superuser\":%s}",
-               first_record ? "" : ",", id, escaped_username, escaped_email,
-               escaped_group, is_superuser ? "true" : "false");
-    } else {
-      snprintf(record, sizeof(record),
-               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
-               "\"%s\",\"is_superuser\":%s}",
-               first_record ? "" : ",", id, escaped_username, escaped_email,
-               escaped_group, is_superuser ? "true" : "false");
-    }
-
-    free(escaped_username);
-    free(escaped_email);
-    free(escaped_group);
-
-    size_t record_len = strlen(record);
-    if (result_size + record_len + 10 > result_capacity) {
-      result_capacity *= 2;
-      char *new_result = realloc(result, result_capacity);
-      if (!new_result) {
-        free(result);
-        sqlite3_finalize(stmt);
-        return nullptr;
-      }
-      result = new_result;
-    }
-    strcat(result, record);
-    result_size += record_len;
-    first_record = 0;
-  }
-
-  if (rc != SQLITE_DONE) {
-    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
-    free(result);
-    sqlite3_finalize(stmt);
-    return NULL;
-  }
-  strcat(result, "]");
-  sqlite3_finalize(stmt);
-  pthread_mutex_unlock(&db_mutex);
-  return result;
+  return sqlite_get_all_users();
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  pthread_mutex_unlock(&users_file_mutex);
-  return data;
+  return filedb_get_all_users();
 #endif
 }
diff --git a/src/db_get_user_by_id.c b/src/db_get_user_by_id.c
index c25a67e..cff7836 100644
--- a/src/db_get_user_by_id.c
+++ b/src/db_get_user_by_id.c
@@ -1,84 +1,15 @@
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "cJSON.h"
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 User *db_get_user_by_id(const int id) {
 #ifdef USE_SQLITE3
-  User *user = nullptr;
-  pthread_mutex_lock(&db_mutex);
-  if (!db) {
-    fprintf(stderr, "Database not initialized\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  sqlite3_stmt *stmt;
-  int rc = sqlite3_prepare_v2(db, SELECT_USER_BY_ID_SQL, -1, &stmt, nullptr);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  sqlite3_bind_int(stmt, 1, id);
-
-  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
-    int id = sqlite3_column_int(stmt, 0);
-    const unsigned char *db_username = sqlite3_column_text(stmt, 1);
-    const unsigned char *db_email = sqlite3_column_text(stmt, 2);
-    const unsigned char *db_password = sqlite3_column_text(stmt, 3);
-    const unsigned char *db_group = sqlite3_column_text(stmt, 4);
-    int db_is_superuser = sqlite3_column_int(stmt, 5);
-    user = new_user(id, (char *) db_username, (char *) db_password,
-                    (char *) db_email, (char *) db_group, db_is_superuser);
-  }
-
-  if (rc != SQLITE_DONE) {
-    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
-    free_user(user);
-    sqlite3_finalize(stmt);
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  pthread_mutex_unlock(&db_mutex);
-  return user;
+  return sqlite_get_user_by_id(id);
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  cJSON *users = cJSON_Parse(data);
-  cJSON *user = nullptr;
-  User *found = nullptr;
-  cJSON_ArrayForEach(user, users) {
-    cJSON *user_id = cJSON_GetObjectItem(user, "id");
-    cJSON *user_username = cJSON_GetObjectItem(user, "username");
-    cJSON *user_password = cJSON_GetObjectItem(user, "password");
-    cJSON *user_email = cJSON_GetObjectItem(user, "email");
-    cJSON *user_group = cJSON_GetObjectItem(user, "group");
-    cJSON *user_is_superuser = cJSON_GetObjectItem(user, "is_superuser");
-    if (user_id->valueint == id) {
-      found = new_user(user_id->valueint, user_username->valuestring,
-                       user_password->valuestring, user_email->valuestring,
-                       user_group->valuestring, user_is_superuser->valueint);
-      break;
-    }
-  }
-  if (found == nullptr) {
-    pthread_mutex_unlock(&users_file_mutex);
-    // if (user != nullptr) cJSON_Delete(user);
-    cJSON_Delete(users);
-    free(data);
-    return nullptr;
-  }
-  pthread_mutex_unlock(&users_file_mutex);
-  // if (user != nullptr) cJSON_Delete(user);
-  cJSON_Delete(users);
-  free(data);
-  return found;
+  return filedb_get_user_by_id(id);
 #endif
 }
diff --git a/src/db_get_user_by_username.c b/src/db_get_user_by_username.c
index 5dc30a5..8766fa6 100644
--- a/src/db_get_user_by_username.c
+++ b/src/db_get_user_by_username.c
@@ -1,84 +1,15 @@
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "cJSON.h"
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 User *db_get_user_by_username(const char *username) {
 #ifdef USE_SQLITE3
-  User *user = nullptr;
-  pthread_mutex_lock(&db_mutex);
-  if (!db) {
-    fprintf(stderr, "Database not initialized\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  sqlite3_stmt *stmt;
-  int rc =
-      sqlite3_prepare_v2(db, SELECT_USER_BY_USERNAME_SQL, -1, &stmt, nullptr);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  sqlite3_bind_text(stmt, 1, username, -1, SQLITE_STATIC);
-
-  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
-    int id = sqlite3_column_int(stmt, 0);
-    const unsigned char *db_username = sqlite3_column_text(stmt, 1);
-    const unsigned char *db_email = sqlite3_column_text(stmt, 2);
-    const unsigned char *db_password = sqlite3_column_text(stmt, 3);
-    const unsigned char *db_group = sqlite3_column_text(stmt, 4);
-    int db_is_superuser = sqlite3_column_int(stmt, 5);
-    user = new_user(id, (char *) db_username, (char *) db_password,
-                    (char *) db_email, (char *) db_group, db_is_superuser);
-  }
-
-  if (rc != SQLITE_DONE) {
-    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
-    free_user(user);
-    sqlite3_finalize(stmt);
-    return nullptr;
-  }
-
-  pthread_mutex_unlock(&db_mutex);
-  return user;
+  return sqlite_get_user_by_username(username);
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  cJSON *users = cJSON_Parse(data);
-  cJSON *user = nullptr;
-  User *found = nullptr;
-  cJSON_ArrayForEach(user, users) {
-    cJSON *user_id = cJSON_GetObjectItem(user, "id");
-    cJSON *user_username = cJSON_GetObjectItem(user, "username");
-    cJSON *user_password = cJSON_GetObjectItem(user, "password");
-    cJSON *user_email = cJSON_GetObjectItem(user, "email");
-    cJSON *user_group = cJSON_GetObjectItem(user, "group");
-    cJSON *user_is_superuser = cJSON_GetObjectItem(user, "is_superuser");
-    if (!strcmp(user_username->valuestring, username)) {
-      found = new_user(user_id->valueint, user_username->valuestring,
-                       user_password->valuestring, user_email->valuestring,
-                       user_group->valuestring, user_is_superuser->valueint);
-      break;
-    }
-  }
-  if (found == nullptr) {
-    pthread_mutex_unlock(&users_file_mutex);
-    // if (user != nullptr) cJSON_Delete(user);
-    cJSON_Delete(users);
-    free(data);
-    return nullptr;
-  }
-  pthread_mutex_unlock(&users_file_mutex);
-  // if (user != nullptr) cJSON_Delete(user);
-  cJSON_Delete(users);
-  free(data);
-  return found;
+  return filedb_get_user_by_username(username);
 #endif
 }
diff --git a/src/db_get_user_field_by_id.c b/src/db_get_user_field_by_id.c
index bb74908..40c6cb3 100644
--- a/src/db_get_user_field_by_id.c
+++ b/src/db_get_user_field_by_id.c
@@ -1,84 +1,15 @@
-#include <pthread.h>
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 char *db_get_user_field_by_id(const int id, const char *field) {
 #ifdef USE_SQLITE3
-  char *password = nullptr;
-  pthread_mutex_lock(&db_mutex);
-  if (!db) {
-    fprintf(stderr, "Database not initialized\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  char sql[256];
-  snprintf(sql, sizeof(sql), SELECT_USER_FIELD_SQL, field);
-  sqlite3_stmt *stmt;
-  int rc = sqlite3_prepare_v2(db, sql, -1, &stmt, nullptr);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  sqlite3_bind_int(stmt, 1, id);
-  rc = sqlite3_step(stmt);
-  if (rc == SQLITE_ROW) {
-    const unsigned char *db_password = sqlite3_column_text(stmt, 0);
-    password = malloc(strlen((const char *) db_password) + 1);
-    if (password) {
-      strcpy(password, (const char *) db_password);
-    }
-    sqlite3_finalize(stmt);
-  } else if (rc == SQLITE_DONE) {
-    fprintf(stderr, "Can't find user");
-    sqlite3_finalize(stmt);
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  } else {
-    fprintf(stderr, "Error executing query: %s\n", sqlite3_errmsg(db));
-    sqlite3_finalize(stmt);
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  pthread_mutex_unlock(&db_mutex);
-  return password;
+  return sqlite_get_user_field_by_id(id, field);
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  cJSON *users = cJSON_Parse(data);
-  cJSON *user = nullptr;
-  User *found = nullptr;
-  cJSON_ArrayForEach(user, users) {
-    cJSON *user_id = cJSON_GetObjectItem(user, "id");
-    cJSON *user_username = cJSON_GetObjectItem(user, "username");
-    cJSON *user_password = cJSON_GetObjectItem(user, "password");
-    cJSON *user_email = cJSON_GetObjectItem(user, "email");
-    cJSON *user_group = cJSON_GetObjectItem(user, "group");
-    cJSON *user_is_superuser = cJSON_GetObjectItem(user, "is_superuser");
-    if (user_id->valueint == id) {
-      found = new_user(user_id->valueint, user_username->valuestring,
-                       user_password->valuestring, user_email->valuestring,
-                       user_group->valuestring, user_is_superuser->valueint);
-      break;
-    }
-  }
-  if (found == nullptr) {
-    pthread_mutex_unlock(&users_file_mutex);
-    // if (user != nullptr) cJSON_Delete(user);
-    cJSON_Delete(users);
-    free(data);
-    return nullptr;
-  }
-  pthread_mutex_unlock(&users_file_mutex);
-  // if (user != nullptr) cJSON_Delete(user);
-  cJSON_Delete(users);
-  free(data);
-  return found->password;
+  return filedb_get_user_field_by_id(id, field);
 #endif
 }
diff --git a/src/db_insert_user.c b/src/db_insert_user.c
index b32f0c2..107d02f 100644
--- a/src/db_insert_user.c
+++ b/src/db_insert_user.c
@@ -1,119 +1,17 @@
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "cJSON.h"
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 User *db_insert_user(const char *username, const char *email,
                      const char *password, const char *group,
                      const bool *is_superuser) {
 #ifdef USE_SQLITE3
-  pthread_mutex_lock(&db_mutex);
-  if (!db) {
-    fprintf(stderr, "Databse not initialized\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  if (!username || !email || !password) {
-    fprintf(stderr, "username, email, password connot be empty\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  const char *sql = nullptr;
-  sqlite3_stmt *stmt;
-  int rc;
-  if (!group || !is_superuser) {
-    sql = INSERT_USER_USERNAME_EMAIL_PASSWORD_SQL;
-  } else if (!group) {
-    sql = INSERT_USER_USERNAME_EMAIL_PASSWORD_GROUP_SQL;
-  } else {
-    sql = INSERT_USER_FULL_SQL;
-  }
-  rc = sqlite3_prepare_v2(db, sql, -1, &stmt, 0);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  sqlite3_bind_text(stmt, 1, username, -1, SQLITE_STATIC);
-  sqlite3_bind_text(stmt, 2, email, -1, SQLITE_STATIC);
-  sqlite3_bind_text(stmt, 3, password, -1, SQLITE_STATIC);
-
-  if (group) {
-    sqlite3_bind_text(stmt, 4, group, -1, SQLITE_STATIC);
-  }
-  if (is_superuser) {
-    sqlite3_bind_int(stmt, 5, *is_superuser);
-  }
-
-  rc = sqlite3_step(stmt);
-  if (rc != SQLITE_DONE) {
-    fprintf(stderr, "Execution failed: %s\n", sqlite3_errmsg(db));
-    sqlite3_finalize(stmt);
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  int inserted_id = sqlite3_last_insert_rowid(db);
-
-  sqlite3_finalize(stmt);
-  printf("User inserted successfully. ID: %d\n", inserted_id);
-  pthread_mutex_unlock(&db_mutex);
-  User *new_db_user =
-      new_user(inserted_id, username, email, password, group, is_superuser);
-  return new_db_user;
+  return sqlite_insert_user(username, email, password, group, is_superuser);
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  cJSON *users = cJSON_Parse(data);
-  cJSON *user = nullptr;
-  int users_size = 0;
-  bool found = false;
-  cJSON_ArrayForEach(user, users) {
-    cJSON *user_username = cJSON_GetObjectItem(user, "username");
-    cJSON *user_password = cJSON_GetObjectItem(user, "password");
-    cJSON *user_email = cJSON_GetObjectItem(user, "email");
-    cJSON *user_group = cJSON_GetObjectItem(user, "group");
-    if (!strcmp(user_username->valuestring, username) &&
-        !strcmp(user_password->valuestring, password) &&
-        !strcmp(user_email->valuestring, email) &&
-        !strcmp(user_group->valuestring, group)) {
-      found = true;
-    }
-    users_size++;
-  }
-  if (found == true) {
-    pthread_mutex_unlock(&users_file_mutex);
-    return nullptr;
-  }
-  cJSON *new_user_data = cJSON_CreateObject();
-  cJSON_AddNumberToObject(new_user_data, "id", users_size);
-  cJSON_AddStringToObject(new_user_data, "username", username);
-  cJSON_AddStringToObject(new_user_data, "password", password);
-  cJSON_AddStringToObject(new_user_data, "email", email);
-  cJSON_AddStringToObject(new_user_data, "group", group);
-  cJSON_AddBoolToObject(new_user_data, "is_superuser", *is_superuser);
-  char *new_user_data_string = cJSON_Print(new_user_data);
-  if (users_size == 0) {
-    users = cJSON_CreateArray();
-  }
-  cJSON_AddItemToArray(users, new_user_data);
-  char *new_data = cJSON_Print(users);
-  write_file("users_db.json", new_data);
-  pthread_mutex_unlock(&users_file_mutex);
-  User *return_user =
-      new_user(users_size, username, email, password, group, is_superuser);
-  free(new_data);
-  free(data);
-  free(new_user_data_string);
-  // cJSON_Delete(new_user_data);
-  cJSON_Delete(users);
-  if (user != nullptr) cJSON_Delete(user);
-  return return_user;
+  return filedb_insert_user(username, email, password, group, is_superuser);
 #endif
 }
diff --git a/src/db_update_user.c b/src/db_update_user.c
index 2707dda..0109069 100644
--- a/src/db_update_user.c
+++ b/src/db_update_user.c
@@ -1,97 +1,19 @@
-#include <pthread.h>
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "cJSON.h"
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 User *db_update_user(const int userid, const char *username, const char *email,
                      const char *password, const char *group,
                      const bool *is_superuser) {
 #ifdef USE_SQLITE3
-  pthread_mutex_lock(&db_mutex);
-  if (!db) {
-    fprintf(stderr, "Databse not initialized\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  if (!username || !email || !password || !group || !is_superuser) {
-    fprintf(stderr,
-            "username, email, password, group, is_superuser connot be empty\n");
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  sqlite3_stmt *stmt;
-  int rc;
-
-  rc = sqlite3_prepare_v2(db, UPDATE_USER_FULL_SQL, -1, &stmt, 0);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "Failed to prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-  sqlite3_bind_text(stmt, 1, username, -1, SQLITE_STATIC);
-  sqlite3_bind_text(stmt, 2, email, -1, SQLITE_STATIC);
-  sqlite3_bind_text(stmt, 3, password, -1, SQLITE_STATIC);
-  sqlite3_bind_text(stmt, 4, group, -1, SQLITE_STATIC);
-  sqlite3_bind_int(stmt, 5, *is_superuser);
-  sqlite3_bind_int(stmt, 6, userid);
-
-  rc = sqlite3_step(stmt);
-  if (rc != SQLITE_DONE) {
-    fprintf(stderr, "Execution failed: %s\n", sqlite3_errmsg(db));
-    sqlite3_finalize(stmt);
-    pthread_mutex_unlock(&db_mutex);
-    return nullptr;
-  }
-
-  int changes = sqlite3_changes(db);
-  sqlite3_finalize(stmt);
-
-  if (changes > 0) {
-    printf("User updated successfully. ID: %d\n", userid);
-  } else {
-    printf("No user found with ID: %d\n", userid);
-    return nullptr;
-  }
-  pthread_mutex_unlock(&db_mutex);
-  return new_user(userid, username, email, password, group, is_superuser);
+  return sqlite_update_user(userid, username, email, password, group,
+                            is_superuser);
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  cJSON *users = cJSON_Parse(data);
-  cJSON *user = nullptr;
-  cJSON_ArrayForEach(user, users) {
-    cJSON *user_id = cJSON_GetObjectItem(user, "id");
-    if (user_id->valueint == userid) {
-      cJSON *user_username = cJSON_GetObjectItem(user, "username");
-      cJSON *user_password = cJSON_GetObjectItem(user, "password");
-      cJSON *user_email = cJSON_GetObjectItem(user, "email");
-      cJSON *user_group = cJSON_GetObjectItem(user, "group");
-      cJSON_SetValuestring(user_username, username);
-      cJSON_SetValuestring(user_password, password);
-      cJSON_SetValuestring(user_email, email);
-      cJSON_SetValuestring(user_group, group);
-      cJSON_DeleteItemFromObject(user, "is_superuser");
-      cJSON_AddBoolToObject(user, "is_superuser", *is_superuser);
-      char *new_data = cJSON_Print(users);
-      write_file("users_db.json", new_data);
-      free(new_data);
-      free(data);
-      cJSON_Delete(users);
-      User *ret =
-          new_user(userid, username, password, email, group, is_superuser);
-      pthread_mutex_unlock(&users_file_mutex);
-      return ret;
-    }
-  }
-  free(data);
-  cJSON_Delete(users);
-  pthread_mutex_unlock(&users_file_mutex);
-  return nullptr;
+  return filedb_update_user(userid, username, email, password, group,
+                            is_superuser);
 #endif
 }
diff --git a/src/db_update_user_field.c b/src/db_update_user_field.c
index 7351093..a4f52f3 100644
--- a/src/db_update_user_field.c
+++ b/src/db_update_user_field.c
@@ -1,75 +1,15 @@
-#include "database.h"
 #include "user.h"
 
 #ifdef USE_SQLITE3
-#include "sql.h"
+#include "sqlite_db/sqlite.h"
 #else
-#include "cJSON.h"
-#include "file.h"
+#include "file_db/filedb.h"
 #endif
 
 bool db_update_user_field(const int id, const char *field, const char *value) {
 #ifdef USE_SQLITE3
-  pthread_mutex_lock(&db_mutex);
-  if (!db || !field || !value) {
-    fprintf(stderr, "invalid parameters\n");
-    pthread_mutex_unlock(&db_mutex);
-    return false;
-  }
-  char sql[256];
-  snprintf(sql, sizeof(sql), UPDATE_USER_FIELD_SQL, field);
-
-  sqlite3_stmt *stmt;
-  int rc = sqlite3_prepare_v2(db, sql, -1, &stmt, 0);
-  if (rc != SQLITE_OK) {
-    fprintf(stderr, "failed to prepare statement: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return false;
-  }
-  sqlite3_bind_text(stmt, 1, value, -1, SQLITE_STATIC);
-  sqlite3_bind_int(stmt, 2, id);
-
-  rc = sqlite3_step(stmt);
-  sqlite3_finalize(stmt);
-
-  if (rc != SQLITE_DONE) {
-    fprintf(stderr, "execution failed: %s\n", sqlite3_errmsg(db));
-    pthread_mutex_unlock(&db_mutex);
-    return false;
-  }
-  pthread_mutex_unlock(&db_mutex);
-  return sqlite3_changes(db) > 0;
+  return sqlite_update_user_field(id, field, value);
 #else
-  pthread_mutex_lock(&users_file_mutex);
-  char *data = read_file("users_db.json");
-  cJSON *users = cJSON_Parse(data);
-  cJSON *user = nullptr;
-  cJSON_ArrayForEach(user, users) {
-    cJSON *user_id = cJSON_GetObjectItem(user, "id");
-    if (user_id->valueint == id) {
-      cJSON *user_field = cJSON_GetObjectItem(user, field);
-      if (cJSON_IsNumber(user_field)) {
-        // cJSON_SetNumberValue(user_field, value);
-        return false;
-      } else if (cJSON_IsBool(user_field)) {
-        // cJSON_DeleteItemFromObject(user, field);
-        // cJSON_AddBoolToObject(user, field, value);
-        return false;
-      } else if (cJSON_IsString(user_field)) {
-        cJSON_SetValuestring(user_field, value);
-      }
-      char *new_data = cJSON_Print(users);
-      write_file("users_db.json", new_data);
-      free(new_data);
-      free(data);
-      cJSON_Delete(users);
-      pthread_mutex_unlock(&users_file_mutex);
-      return true;
-    }
-  }
-  free(data);
-  cJSON_Delete(users);
-  pthread_mutex_unlock(&users_file_mutex);
-  return false;
+  return filedb_update_user_field(id, field, value);
 #endif
 }
diff --git a/src/file_db/filedb.c b/src/file_db/filedb.c
new file mode 100644
index 0000000..3c9fab1
--- /dev/null
+++ b/src/file_db/filedb.c
@@ -0,0 +1,4 @@
+#include "filedb.h"
+#include <pthread.h>
+
+pthread_mutex_t users_file_mutex = PTHREAD_MUTEX_INITIALIZER;
diff --git a/src/file_db/filedb.h b/src/file_db/filedb.h
new file mode 100644
index 0000000..d861fff
--- /dev/null
+++ b/src/file_db/filedb.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include "../user.h"
+
+extern pthread_mutex_t users_file_mutex;
+
+bool filedb_delete_user(const int id);
+char *filedb_get_all_users();
+User *filedb_get_user_by_id(const int id);
+User *filedb_get_user_by_username(const char *username);
+char *filedb_get_user_field_by_id(const int id, const char *field);
+User *filedb_insert_user(const char *username, const char *email,
+                         const char *password, const char *group,
+                         const bool *is_superuser);
+User *filedb_update_user(const int userid, const char *username,
+                         const char *email, const char *password,
+                         const char *group, const bool *is_superuser);
+bool filedb_update_user_field(const int id, const char *field,
+                              const char *value);
diff --git a/src/file_db/filedb_delete_user.c b/src/file_db/filedb_delete_user.c
new file mode 100644
index 0000000..257430b
--- /dev/null
+++ b/src/file_db/filedb_delete_user.c
@@ -0,0 +1,34 @@
+#include <pthread.h>
+#include <stdlib.h>
+#include "../file.h"
+#include "cJSON.h"
+#include "filedb.h"
+
+bool filedb_delete_user(const int id) {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  cJSON *users = cJSON_Parse(data);
+  cJSON *user = nullptr;
+  int index = 0;
+  bool found = false;
+  cJSON_ArrayForEach(user, users) {
+    cJSON *user_id = cJSON_GetObjectItem(user, "id");
+    if (user_id->valueint == id) {
+      cJSON_DeleteItemFromArray(users, index);
+      found = true;
+      break;
+    }
+    index++;
+  }
+  if (!found) {
+    pthread_mutex_unlock(&users_file_mutex);
+    return false;
+  }
+  char *new_data = cJSON_Print(users);
+  write_file("users_db.json", new_data);
+  free(new_data);
+  free(data);
+  cJSON_Delete(users);
+  pthread_mutex_unlock(&users_file_mutex);
+  return true;
+}
diff --git a/src/file_db/filedb_get_all_users.c b/src/file_db/filedb_get_all_users.c
new file mode 100644
index 0000000..d20c3b4
--- /dev/null
+++ b/src/file_db/filedb_get_all_users.c
@@ -0,0 +1,10 @@
+#include <pthread.h>
+#include "../file.h"
+#include "filedb.h"
+
+char *filedb_get_all_users() {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  pthread_mutex_unlock(&users_file_mutex);
+  return data;
+}
diff --git a/src/file_db/filedb_get_user_by_id.c b/src/file_db/filedb_get_user_by_id.c
new file mode 100644
index 0000000..88be3b2
--- /dev/null
+++ b/src/file_db/filedb_get_user_by_id.c
@@ -0,0 +1,37 @@
+#include <pthread.h>
+#include "../file.h"
+#include "filedb.h"
+
+User *filedb_get_user_by_id(const int id) {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  cJSON *users = cJSON_Parse(data);
+  cJSON *user = nullptr;
+  User *found = nullptr;
+  cJSON_ArrayForEach(user, users) {
+    cJSON *user_id = cJSON_GetObjectItem(user, "id");
+    cJSON *user_username = cJSON_GetObjectItem(user, "username");
+    cJSON *user_password = cJSON_GetObjectItem(user, "password");
+    cJSON *user_email = cJSON_GetObjectItem(user, "email");
+    cJSON *user_group = cJSON_GetObjectItem(user, "group");
+    cJSON *user_is_superuser = cJSON_GetObjectItem(user, "is_superuser");
+    if (user_id->valueint == id) {
+      found = new_user(user_id->valueint, user_username->valuestring,
+                       user_password->valuestring, user_email->valuestring,
+                       user_group->valuestring, user_is_superuser->valueint);
+      break;
+    }
+  }
+  if (found == nullptr) {
+    pthread_mutex_unlock(&users_file_mutex);
+    // if (user != nullptr) cJSON_Delete(user);
+    cJSON_Delete(users);
+    free(data);
+    return nullptr;
+  }
+  pthread_mutex_unlock(&users_file_mutex);
+  // if (user != nullptr) cJSON_Delete(user);
+  cJSON_Delete(users);
+  free(data);
+  return found;
+}
diff --git a/src/file_db/filedb_get_user_by_username.c b/src/file_db/filedb_get_user_by_username.c
new file mode 100644
index 0000000..65ef941
--- /dev/null
+++ b/src/file_db/filedb_get_user_by_username.c
@@ -0,0 +1,37 @@
+#include <pthread.h>
+#include "../file.h"
+#include "filedb.h"
+
+User *filedb_get_user_by_username(const char *username) {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  cJSON *users = cJSON_Parse(data);
+  cJSON *user = nullptr;
+  User *found = nullptr;
+  cJSON_ArrayForEach(user, users) {
+    cJSON *user_id = cJSON_GetObjectItem(user, "id");
+    cJSON *user_username = cJSON_GetObjectItem(user, "username");
+    cJSON *user_password = cJSON_GetObjectItem(user, "password");
+    cJSON *user_email = cJSON_GetObjectItem(user, "email");
+    cJSON *user_group = cJSON_GetObjectItem(user, "group");
+    cJSON *user_is_superuser = cJSON_GetObjectItem(user, "is_superuser");
+    if (!strcmp(user_username->valuestring, username)) {
+      found = new_user(user_id->valueint, user_username->valuestring,
+                       user_password->valuestring, user_email->valuestring,
+                       user_group->valuestring, user_is_superuser->valueint);
+      break;
+    }
+  }
+  if (found == nullptr) {
+    pthread_mutex_unlock(&users_file_mutex);
+    // if (user != nullptr) cJSON_Delete(user);
+    cJSON_Delete(users);
+    free(data);
+    return nullptr;
+  }
+  pthread_mutex_unlock(&users_file_mutex);
+  // if (user != nullptr) cJSON_Delete(user);
+  cJSON_Delete(users);
+  free(data);
+  return found;
+}
diff --git a/src/file_db/filedb_get_user_field_by_id.c b/src/file_db/filedb_get_user_field_by_id.c
new file mode 100644
index 0000000..82859de
--- /dev/null
+++ b/src/file_db/filedb_get_user_field_by_id.c
@@ -0,0 +1,37 @@
+#include <pthread.h>
+#include "../file.h"
+#include "filedb.h"
+
+char *filedb_get_user_field_by_id(const int id, const char *field) {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  cJSON *users = cJSON_Parse(data);
+  cJSON *user = nullptr;
+  User *found = nullptr;
+  cJSON_ArrayForEach(user, users) {
+    cJSON *user_id = cJSON_GetObjectItem(user, "id");
+    cJSON *user_username = cJSON_GetObjectItem(user, "username");
+    cJSON *user_password = cJSON_GetObjectItem(user, "password");
+    cJSON *user_email = cJSON_GetObjectItem(user, "email");
+    cJSON *user_group = cJSON_GetObjectItem(user, "group");
+    cJSON *user_is_superuser = cJSON_GetObjectItem(user, "is_superuser");
+    if (user_id->valueint == id) {
+      found = new_user(user_id->valueint, user_username->valuestring,
+                       user_password->valuestring, user_email->valuestring,
+                       user_group->valuestring, user_is_superuser->valueint);
+      break;
+    }
+  }
+  if (found == nullptr) {
+    pthread_mutex_unlock(&users_file_mutex);
+    // if (user != nullptr) cJSON_Delete(user);
+    cJSON_Delete(users);
+    free(data);
+    return nullptr;
+  }
+  pthread_mutex_unlock(&users_file_mutex);
+  // if (user != nullptr) cJSON_Delete(user);
+  cJSON_Delete(users);
+  free(data);
+  return found->password;
+}
diff --git a/src/file_db/filedb_insert_user.c b/src/file_db/filedb_insert_user.c
new file mode 100644
index 0000000..89da731
--- /dev/null
+++ b/src/file_db/filedb_insert_user.c
@@ -0,0 +1,55 @@
+#include <pthread.h>
+#include "../file.h"
+#include "filedb.h"
+
+User *filedb_insert_user(const char *username, const char *email,
+                         const char *password, const char *group,
+                         const bool *is_superuser) {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  cJSON *users = cJSON_Parse(data);
+  cJSON *user = nullptr;
+  int users_size = 0;
+  bool found = false;
+  cJSON_ArrayForEach(user, users) {
+    cJSON *user_username = cJSON_GetObjectItem(user, "username");
+    cJSON *user_password = cJSON_GetObjectItem(user, "password");
+    cJSON *user_email = cJSON_GetObjectItem(user, "email");
+    cJSON *user_group = cJSON_GetObjectItem(user, "group");
+    if (!strcmp(user_username->valuestring, username) &&
+        !strcmp(user_password->valuestring, password) &&
+        !strcmp(user_email->valuestring, email) &&
+        !strcmp(user_group->valuestring, group)) {
+      found = true;
+    }
+    users_size++;
+  }
+  if (found == true) {
+    pthread_mutex_unlock(&users_file_mutex);
+    return nullptr;
+  }
+  cJSON *new_user_data = cJSON_CreateObject();
+  cJSON_AddNumberToObject(new_user_data, "id", users_size);
+  cJSON_AddStringToObject(new_user_data, "username", username);
+  cJSON_AddStringToObject(new_user_data, "password", password);
+  cJSON_AddStringToObject(new_user_data, "email", email);
+  cJSON_AddStringToObject(new_user_data, "group", group);
+  cJSON_AddBoolToObject(new_user_data, "is_superuser", *is_superuser);
+  char *new_user_data_string = cJSON_Print(new_user_data);
+  if (users_size == 0) {
+    users = cJSON_CreateArray();
+  }
+  cJSON_AddItemToArray(users, new_user_data);
+  char *new_data = cJSON_Print(users);
+  write_file("users_db.json", new_data);
+  pthread_mutex_unlock(&users_file_mutex);
+  User *return_user =
+      new_user(users_size, username, email, password, group, is_superuser);
+  free(new_data);
+  free(data);
+  free(new_user_data_string);
+  // cJSON_Delete(new_user_data);
+  cJSON_Delete(users);
+  if (user != nullptr) cJSON_Delete(user);
+  return return_user;
+}
diff --git a/src/file_db/filedb_update_user.c b/src/file_db/filedb_update_user.c
new file mode 100644
index 0000000..06593d8
--- /dev/null
+++ b/src/file_db/filedb_update_user.c
@@ -0,0 +1,40 @@
+#include <pthread.h>
+#include "../file.h"
+#include "filedb.h"
+
+User *filedb_update_user(const int userid, const char *username,
+                         const char *email, const char *password,
+                         const char *group, const bool *is_superuser) {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  cJSON *users = cJSON_Parse(data);
+  cJSON *user = nullptr;
+  cJSON_ArrayForEach(user, users) {
+    cJSON *user_id = cJSON_GetObjectItem(user, "id");
+    if (user_id->valueint == userid) {
+      cJSON *user_username = cJSON_GetObjectItem(user, "username");
+      cJSON *user_password = cJSON_GetObjectItem(user, "password");
+      cJSON *user_email = cJSON_GetObjectItem(user, "email");
+      cJSON *user_group = cJSON_GetObjectItem(user, "group");
+      cJSON_SetValuestring(user_username, username);
+      cJSON_SetValuestring(user_password, password);
+      cJSON_SetValuestring(user_email, email);
+      cJSON_SetValuestring(user_group, group);
+      cJSON_DeleteItemFromObject(user, "is_superuser");
+      cJSON_AddBoolToObject(user, "is_superuser", *is_superuser);
+      char *new_data = cJSON_Print(users);
+      write_file("users_db.json", new_data);
+      free(new_data);
+      free(data);
+      cJSON_Delete(users);
+      User *ret =
+          new_user(userid, username, password, email, group, is_superuser);
+      pthread_mutex_unlock(&users_file_mutex);
+      return ret;
+    }
+  }
+  free(data);
+  cJSON_Delete(users);
+  pthread_mutex_unlock(&users_file_mutex);
+  return nullptr;
+}
diff --git a/src/file_db/filedb_update_user_field.c b/src/file_db/filedb_update_user_field.c
new file mode 100644
index 0000000..fd386ff
--- /dev/null
+++ b/src/file_db/filedb_update_user_field.c
@@ -0,0 +1,38 @@
+#include <pthread.h>
+#include "../file.h"
+#include "filedb.h"
+
+bool filedb_update_user_field(const int id, const char *field,
+                              const char *value) {
+  pthread_mutex_lock(&users_file_mutex);
+  char *data = read_file("users_db.json");
+  cJSON *users = cJSON_Parse(data);
+  cJSON *user = nullptr;
+  cJSON_ArrayForEach(user, users) {
+    cJSON *user_id = cJSON_GetObjectItem(user, "id");
+    if (user_id->valueint == id) {
+      cJSON *user_field = cJSON_GetObjectItem(user, field);
+      if (cJSON_IsNumber(user_field)) {
+        // cJSON_SetNumberValue(user_field, value);
+        return false;
+      } else if (cJSON_IsBool(user_field)) {
+        // cJSON_DeleteItemFromObject(user, field);
+        // cJSON_AddBoolToObject(user, field, value);
+        return false;
+      } else if (cJSON_IsString(user_field)) {
+        cJSON_SetValuestring(user_field, value);
+      }
+      char *new_data = cJSON_Print(users);
+      write_file("users_db.json", new_data);
+      free(new_data);
+      free(data);
+      cJSON_Delete(users);
+      pthread_mutex_unlock(&users_file_mutex);
+      return true;
+    }
+  }
+  free(data);
+  cJSON_Delete(users);
+  pthread_mutex_unlock(&users_file_mutex);
+  return false;
+}
diff --git a/src/sql.h b/src/sqlite_db/sql.h
similarity index 100%
rename from src/sql.h
rename to src/sqlite_db/sql.h
diff --git a/src/sqlite_db/sqlite.c b/src/sqlite_db/sqlite.c
new file mode 100644
index 0000000..0d4f27b
--- /dev/null
+++ b/src/sqlite_db/sqlite.c
@@ -0,0 +1,5 @@
+#include "sqlite.h"
+#include "pthread.h"
+
+sqlite3 *db = nullptr;
+pthread_mutex_t db_mutex = PTHREAD_MUTEX_INITIALIZER;
diff --git a/src/sqlite_db/sqlite.h b/src/sqlite_db/sqlite.h
new file mode 100644
index 0000000..926a09f
--- /dev/null
+++ b/src/sqlite_db/sqlite.h
@@ -0,0 +1,23 @@
+#pragma once
+
+#include <sqlite3.h>
+#include "../user.h"
+
+extern sqlite3 *db;
+extern pthread_mutex_t db_mutex;
+
+void sqlite_init_db();
+void sqlite_migrate_db();
+bool sqlite_delete_user(const int id);
+char *sqlite_get_all_users();
+User *sqlite_get_user_by_id(const int id);
+User *sqlite_get_user_by_username(const char *username);
+char *sqlite_get_user_field_by_id(const int id, const char *field);
+User *sqlite_insert_user(const char *username, const char *email,
+                         const char *password, const char *group,
+                         const bool *is_superuser);
+User *sqlite_update_user(const int userid, const char *username,
+                         const char *email, const char *password,
+                         const char *group, const bool *is_superuser);
+bool sqlite_update_user_field(const int id, const char *field,
+                              const char *value);
diff --git a/src/sqlite_db/sqlite_delete_user.c b/src/sqlite_db/sqlite_delete_user.c
new file mode 100644
index 0000000..7c8f54a
--- /dev/null
+++ b/src/sqlite_db/sqlite_delete_user.c
@@ -0,0 +1,46 @@
+#include "sqlite.h"
+#include "sql.h"
+#include <stdio.h>
+#include "pthread.h"
+
+bool sqlite_delete_user(const int id) {
+    pthread_mutex_lock(&db_mutex);
+    if (!db) {
+      fprintf(stderr, "Database not initialized\n");
+      pthread_mutex_unlock(&db_mutex);
+      return false;
+    }
+    sqlite3_stmt *stmt;
+    int rc;
+
+    rc = sqlite3_prepare_v2(db, DELETE_USER_SQL, -1, &stmt, 0);
+    if (rc != SQLITE_OK) {
+      fprintf(stderr, "Failed to prepare statement: %s\n", sqlite3_errmsg(db));
+      pthread_mutex_unlock(&db_mutex);
+      return false;
+    }
+
+    sqlite3_bind_int(stmt, 1, id);
+
+    rc = sqlite3_step(stmt);
+    if (rc != SQLITE_DONE) {
+      fprintf(stderr, "Execution failed: %s\n", sqlite3_errmsg(db));
+      sqlite3_finalize(stmt);
+      pthread_mutex_unlock(&db_mutex);
+      return false;
+    }
+
+    int changes = sqlite3_changes(db);
+    sqlite3_finalize(stmt);
+
+    if (changes > 0) {
+      printf("User deleted successfully. ID: %d\n", id);
+    } else {
+      printf("No user found with ID: %d\n", id);
+      pthread_mutex_unlock(&db_mutex);
+      return false;
+    }
+
+    pthread_mutex_unlock(&db_mutex);
+    return true;
+}
diff --git a/src/sqlite_db/sqlite_get_all_users.c b/src/sqlite_db/sqlite_get_all_users.c
new file mode 100644
index 0000000..556ae62
--- /dev/null
+++ b/src/sqlite_db/sqlite_get_all_users.c
@@ -0,0 +1,102 @@
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "../database.h"
+#include "sql.h"
+#include "sqlite.h"
+
+char *sqlite_get_all_users() {
+  pthread_mutex_lock(&db_mutex);
+  if (!db) {
+    fprintf(stderr, "Database not initialized\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  sqlite3_stmt *stmt;
+  int rc;
+
+  rc = sqlite3_prepare_v2(db, SELECT_ALL_USERS_SQL, -1, &stmt, nullptr);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  char *result = malloc(1024);
+  if (!result) {
+    sqlite3_finalize(stmt);
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  strcpy(result, "[");
+  size_t result_size = strlen(result);
+  size_t result_capacity = 1024;
+
+  int first_record = 1;
+
+  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
+    int id = sqlite3_column_int(stmt, 0);
+    const unsigned char *username = sqlite3_column_text(stmt, 1);
+    const unsigned char *email = sqlite3_column_text(stmt, 2);
+    const unsigned char *group = sqlite3_column_text(stmt, 4);
+    int is_superuser = sqlite3_column_int(stmt, 5);
+
+    char *escaped_username = json_escape((const char *) username);
+    char *escaped_email = json_escape((const char *) email);
+    char *escaped_group = json_escape((const char *) group);
+    if (!escaped_username || !escaped_email || !escaped_group) {
+      free(escaped_username);
+      free(escaped_email);
+      free(escaped_group);
+      sqlite3_finalize(stmt);
+      return NULL;
+    }
+
+    char record[512];
+    if (sqlite3_column_type(stmt, 2) == SQLITE_NULL) {
+      snprintf(record, sizeof(record),
+               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
+               "\"%s\",\"is_superuser\":%s}",
+               first_record ? "" : ",", id, escaped_username, escaped_email,
+               escaped_group, is_superuser ? "true" : "false");
+    } else {
+      snprintf(record, sizeof(record),
+               "%s{\"id\":%d,\"username\":\"%s\",\"email\":\"%s\",\"group\":"
+               "\"%s\",\"is_superuser\":%s}",
+               first_record ? "" : ",", id, escaped_username, escaped_email,
+               escaped_group, is_superuser ? "true" : "false");
+    }
+
+    free(escaped_username);
+    free(escaped_email);
+    free(escaped_group);
+
+    size_t record_len = strlen(record);
+    if (result_size + record_len + 10 > result_capacity) {
+      result_capacity *= 2;
+      char *new_result = realloc(result, result_capacity);
+      if (!new_result) {
+        free(result);
+        sqlite3_finalize(stmt);
+        return nullptr;
+      }
+      result = new_result;
+    }
+    strcat(result, record);
+    result_size += record_len;
+    first_record = 0;
+  }
+
+  if (rc != SQLITE_DONE) {
+    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
+    free(result);
+    sqlite3_finalize(stmt);
+    return NULL;
+  }
+  strcat(result, "]");
+  sqlite3_finalize(stmt);
+  pthread_mutex_unlock(&db_mutex);
+  return result;
+}
diff --git a/src/sqlite_db/sqlite_get_user_by_id.c b/src/sqlite_db/sqlite_get_user_by_id.c
new file mode 100644
index 0000000..7058297
--- /dev/null
+++ b/src/sqlite_db/sqlite_get_user_by_id.c
@@ -0,0 +1,44 @@
+#include "sql.h"
+#include "sqlite.h"
+#include "pthread.h"
+
+User *sqlite_get_user_by_id(const int id) {
+  User *user = nullptr;
+  pthread_mutex_lock(&db_mutex);
+  if (!db) {
+    fprintf(stderr, "Database not initialized\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  sqlite3_stmt *stmt;
+  int rc = sqlite3_prepare_v2(db, SELECT_USER_BY_ID_SQL, -1, &stmt, nullptr);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  sqlite3_bind_int(stmt, 1, id);
+
+  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
+    int id = sqlite3_column_int(stmt, 0);
+    const unsigned char *db_username = sqlite3_column_text(stmt, 1);
+    const unsigned char *db_email = sqlite3_column_text(stmt, 2);
+    const unsigned char *db_password = sqlite3_column_text(stmt, 3);
+    const unsigned char *db_group = sqlite3_column_text(stmt, 4);
+    int db_is_superuser = sqlite3_column_int(stmt, 5);
+    user = new_user(id, (char *) db_username, (char *) db_password,
+                    (char *) db_email, (char *) db_group, db_is_superuser);
+  }
+
+  if (rc != SQLITE_DONE) {
+    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
+    free_user(user);
+    sqlite3_finalize(stmt);
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  pthread_mutex_unlock(&db_mutex);
+  return user;
+}
diff --git a/src/sqlite_db/sqlite_get_user_by_username.c b/src/sqlite_db/sqlite_get_user_by_username.c
new file mode 100644
index 0000000..1c5bf21
--- /dev/null
+++ b/src/sqlite_db/sqlite_get_user_by_username.c
@@ -0,0 +1,44 @@
+#include "sql.h"
+#include "sqlite.h"
+#include "pthread.h"
+
+User *sqlite_get_user_by_username(const char *username) {
+  User *user = nullptr;
+  pthread_mutex_lock(&db_mutex);
+  if (!db) {
+    fprintf(stderr, "Database not initialized\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  sqlite3_stmt *stmt;
+  int rc =
+      sqlite3_prepare_v2(db, SELECT_USER_BY_USERNAME_SQL, -1, &stmt, nullptr);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  sqlite3_bind_text(stmt, 1, username, -1, SQLITE_STATIC);
+
+  while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
+    int id = sqlite3_column_int(stmt, 0);
+    const unsigned char *db_username = sqlite3_column_text(stmt, 1);
+    const unsigned char *db_email = sqlite3_column_text(stmt, 2);
+    const unsigned char *db_password = sqlite3_column_text(stmt, 3);
+    const unsigned char *db_group = sqlite3_column_text(stmt, 4);
+    int db_is_superuser = sqlite3_column_int(stmt, 5);
+    user = new_user(id, (char *) db_username, (char *) db_password,
+                    (char *) db_email, (char *) db_group, db_is_superuser);
+  }
+
+  if (rc != SQLITE_DONE) {
+    fprintf(stderr, "Error reading data: %s\n", sqlite3_errmsg(db));
+    free_user(user);
+    sqlite3_finalize(stmt);
+    return nullptr;
+  }
+
+  pthread_mutex_unlock(&db_mutex);
+  return user;
+}
diff --git a/src/sqlite_db/sqlite_get_user_field_by_id.c b/src/sqlite_db/sqlite_get_user_field_by_id.c
new file mode 100644
index 0000000..a58f823
--- /dev/null
+++ b/src/sqlite_db/sqlite_get_user_field_by_id.c
@@ -0,0 +1,44 @@
+#include "pthread.h"
+#include "sql.h"
+#include "sqlite.h"
+
+char *sqlite_get_user_field_by_id(const int id, const char *field) {
+  char *password = nullptr;
+  pthread_mutex_lock(&db_mutex);
+  if (!db) {
+    fprintf(stderr, "Database not initialized\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  char sql[256];
+  snprintf(sql, sizeof(sql), SELECT_USER_FIELD_SQL, field);
+  sqlite3_stmt *stmt;
+  int rc = sqlite3_prepare_v2(db, sql, -1, &stmt, nullptr);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  sqlite3_bind_int(stmt, 1, id);
+  rc = sqlite3_step(stmt);
+  if (rc == SQLITE_ROW) {
+    const unsigned char *db_password = sqlite3_column_text(stmt, 0);
+    password = malloc(strlen((const char *) db_password) + 1);
+    if (password) {
+      strcpy(password, (const char *) db_password);
+    }
+    sqlite3_finalize(stmt);
+  } else if (rc == SQLITE_DONE) {
+    fprintf(stderr, "Can't find user");
+    sqlite3_finalize(stmt);
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  } else {
+    fprintf(stderr, "Error executing query: %s\n", sqlite3_errmsg(db));
+    sqlite3_finalize(stmt);
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  pthread_mutex_unlock(&db_mutex);
+  return password;
+}
diff --git a/src/sqlite_db/sqlite_init_db.c b/src/sqlite_db/sqlite_init_db.c
new file mode 100644
index 0000000..8af19c9
--- /dev/null
+++ b/src/sqlite_db/sqlite_init_db.c
@@ -0,0 +1,11 @@
+#include "../config.h"
+#include "sqlite.h"
+
+void sqlite_init_db() {
+  if (sqlite3_open(cm_get_parameter_as_string(config, "database"), &db) !=
+      SQLITE_OK) {
+    fprintf(stderr, "Cannot open database: %s\n", sqlite3_errmsg(db));
+    sqlite3_close(db);
+    exit(1);
+  }
+}
diff --git a/src/sqlite_db/sqlite_insert_user.c b/src/sqlite_db/sqlite_insert_user.c
new file mode 100644
index 0000000..37e1a39
--- /dev/null
+++ b/src/sqlite_db/sqlite_insert_user.c
@@ -0,0 +1,63 @@
+#include "pthread.h"
+#include "sql.h"
+#include "sqlite.h"
+
+User *sqlite_insert_user(const char *username, const char *email,
+                         const char *password, const char *group,
+                         const bool *is_superuser) {
+  pthread_mutex_lock(&db_mutex);
+  if (!db) {
+    fprintf(stderr, "Databse not initialized\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  if (!username || !email || !password) {
+    fprintf(stderr, "username, email, password connot be empty\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  const char *sql = nullptr;
+  sqlite3_stmt *stmt;
+  int rc;
+  if (!group || !is_superuser) {
+    sql = INSERT_USER_USERNAME_EMAIL_PASSWORD_SQL;
+  } else if (!group) {
+    sql = INSERT_USER_USERNAME_EMAIL_PASSWORD_GROUP_SQL;
+  } else {
+    sql = INSERT_USER_FULL_SQL;
+  }
+  rc = sqlite3_prepare_v2(db, sql, -1, &stmt, 0);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "Cannot prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  sqlite3_bind_text(stmt, 1, username, -1, SQLITE_STATIC);
+  sqlite3_bind_text(stmt, 2, email, -1, SQLITE_STATIC);
+  sqlite3_bind_text(stmt, 3, password, -1, SQLITE_STATIC);
+
+  if (group) {
+    sqlite3_bind_text(stmt, 4, group, -1, SQLITE_STATIC);
+  }
+  if (is_superuser) {
+    sqlite3_bind_int(stmt, 5, *is_superuser);
+  }
+
+  rc = sqlite3_step(stmt);
+  if (rc != SQLITE_DONE) {
+    fprintf(stderr, "Execution failed: %s\n", sqlite3_errmsg(db));
+    sqlite3_finalize(stmt);
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  int inserted_id = sqlite3_last_insert_rowid(db);
+
+  sqlite3_finalize(stmt);
+  printf("User inserted successfully. ID: %d\n", inserted_id);
+  pthread_mutex_unlock(&db_mutex);
+  User *new_db_user =
+      new_user(inserted_id, username, email, password, group, is_superuser);
+  return new_db_user;
+}
diff --git a/src/sqlite_db/sqlite_migrate_db.c b/src/sqlite_db/sqlite_migrate_db.c
new file mode 100644
index 0000000..d145803
--- /dev/null
+++ b/src/sqlite_db/sqlite_migrate_db.c
@@ -0,0 +1,16 @@
+#include "pthread.h"
+#include "sql.h"
+#include "sqlite.h"
+
+void sqlite_migrate_db() {
+  char *err_msg = 0;
+  pthread_mutex_lock(&db_mutex);
+  if (sqlite3_exec(db, CREATE_TABLE_USERS, nullptr, nullptr, &err_msg) !=
+      SQLITE_OK) {
+    fprintf(stderr, "SQL error: %s\n", err_msg);
+    sqlite3_free(err_msg);
+    sqlite3_close(db);
+    exit(1);
+  }
+  pthread_mutex_unlock(&db_mutex);
+}
diff --git a/src/sqlite_db/sqlite_update_user.c b/src/sqlite_db/sqlite_update_user.c
new file mode 100644
index 0000000..457265c
--- /dev/null
+++ b/src/sqlite_db/sqlite_update_user.c
@@ -0,0 +1,55 @@
+#include "pthread.h"
+#include "sql.h"
+#include "sqlite.h"
+
+User *sqlite_update_user(const int userid, const char *username,
+                         const char *email, const char *password,
+                         const char *group, const bool *is_superuser) {
+  pthread_mutex_lock(&db_mutex);
+  if (!db) {
+    fprintf(stderr, "Databse not initialized\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  if (!username || !email || !password || !group || !is_superuser) {
+    fprintf(stderr,
+            "username, email, password, group, is_superuser connot be empty\n");
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  sqlite3_stmt *stmt;
+  int rc;
+
+  rc = sqlite3_prepare_v2(db, UPDATE_USER_FULL_SQL, -1, &stmt, 0);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "Failed to prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+  sqlite3_bind_text(stmt, 1, username, -1, SQLITE_STATIC);
+  sqlite3_bind_text(stmt, 2, email, -1, SQLITE_STATIC);
+  sqlite3_bind_text(stmt, 3, password, -1, SQLITE_STATIC);
+  sqlite3_bind_text(stmt, 4, group, -1, SQLITE_STATIC);
+  sqlite3_bind_int(stmt, 5, *is_superuser);
+  sqlite3_bind_int(stmt, 6, userid);
+
+  rc = sqlite3_step(stmt);
+  if (rc != SQLITE_DONE) {
+    fprintf(stderr, "Execution failed: %s\n", sqlite3_errmsg(db));
+    sqlite3_finalize(stmt);
+    pthread_mutex_unlock(&db_mutex);
+    return nullptr;
+  }
+
+  int changes = sqlite3_changes(db);
+  sqlite3_finalize(stmt);
+
+  if (changes > 0) {
+    printf("User updated successfully. ID: %d\n", userid);
+  } else {
+    printf("No user found with ID: %d\n", userid);
+    return nullptr;
+  }
+  pthread_mutex_unlock(&db_mutex);
+  return new_user(userid, username, email, password, group, is_superuser);
+}
diff --git a/src/sqlite_db/sqlite_update_user_field.c b/src/sqlite_db/sqlite_update_user_field.c
new file mode 100644
index 0000000..93c202d
--- /dev/null
+++ b/src/sqlite_db/sqlite_update_user_field.c
@@ -0,0 +1,36 @@
+#include "pthread.h"
+#include "sql.h"
+#include "sqlite.h"
+
+bool sqlite_update_user_field(const int id, const char *field,
+                              const char *value) {
+  pthread_mutex_lock(&db_mutex);
+  if (!db || !field || !value) {
+    fprintf(stderr, "invalid parameters\n");
+    pthread_mutex_unlock(&db_mutex);
+    return false;
+  }
+  char sql[256];
+  snprintf(sql, sizeof(sql), UPDATE_USER_FIELD_SQL, field);
+
+  sqlite3_stmt *stmt;
+  int rc = sqlite3_prepare_v2(db, sql, -1, &stmt, 0);
+  if (rc != SQLITE_OK) {
+    fprintf(stderr, "failed to prepare statement: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return false;
+  }
+  sqlite3_bind_text(stmt, 1, value, -1, SQLITE_STATIC);
+  sqlite3_bind_int(stmt, 2, id);
+
+  rc = sqlite3_step(stmt);
+  sqlite3_finalize(stmt);
+
+  if (rc != SQLITE_DONE) {
+    fprintf(stderr, "execution failed: %s\n", sqlite3_errmsg(db));
+    pthread_mutex_unlock(&db_mutex);
+    return false;
+  }
+  pthread_mutex_unlock(&db_mutex);
+  return sqlite3_changes(db) > 0;
+}