diff --git a/iFacility/db/database.cpp b/iFacility/db/database.cpp
new file mode 100644
index 0000000..d0ed8d3
--- /dev/null
+++ b/iFacility/db/database.cpp
@@ -0,0 +1,79 @@
+#include "database.h"
+
+Database *Database::mInstance = new Database();
+const QString Database::mFilename = "data.bin";
+
+Database* Database::instance() {
+    return Database::mInstance;
+}
+
+QVector<Profession> Database::professions() const {
+    return mProfessions;
+}
+
+QVector<User> Database::users() const {
+    return mUsers;
+}
+
+bool Database::addUser(User usr) {
+    if (getUser(usr.getLogin()) != nullptr) {
+        return false;
+    }
+    mUsers.push_back(usr);
+    return true;
+}
+
+QVector<User*> Database::findUserByPredicat(UserPredicat predicat) {
+    QVector<User*> out;
+    auto it = mUsers.begin();
+    while (it != mUsers.end()) {
+        it = std::find_if(it, mUsers.end(), predicat);
+        if (it != mUsers.end()) {
+            out.push_back(it++);
+        }
+    }
+    return out;
+}
+
+User* Database::getUser(UID uid) {
+    auto pred = [uid](User u) { return u.uID() == uid; };
+    auto users = findUserByPredicat(pred);
+    return users.isEmpty()? nullptr : users[0];
+}
+
+User* Database::getUser(QString login) {
+    auto pred = [login](User u) { return u.getLogin() == login; };
+    auto users = findUserByPredicat(pred);
+    return users.isEmpty()? nullptr : users[0];
+}
+
+QVector<User*> Database::getUsersByType(UserType type) {
+    auto pred = [type](User u) { return u.getUserType() == type; };
+    return findUserByPredicat(pred);
+}
+
+QVector<User*> Database::getUsersByProfession(Profession prof) {
+    auto pred = [prof](User u) { return u.hasProfession(prof.pID()); };
+    return findUserByPredicat(pred);
+}
+
+void Database::save() {
+    QFile f(Database::mFilename);
+    f.open(QIODevice::ReadOnly);
+    QDataStream stream(&f);
+    stream << mProfessions << mUsers;
+    f.close();
+}
+
+void Database::load() {
+    if (!QFile().exists(Database::mFilename)) {
+        return;
+    }
+    mUsers.clear();
+    mProfessions.clear();
+    QFile f(Database::mFilename);
+    f.open(QIODevice::WriteOnly);
+    QDataStream stream(&f);
+    stream >> mProfessions >> mUsers;
+    f.close();
+}
diff --git a/iFacility/db/database.h b/iFacility/db/database.h
new file mode 100644
index 0000000..73f09a0
--- /dev/null
+++ b/iFacility/db/database.h
@@ -0,0 +1,45 @@
+#ifndef DATABASE_H
+#define DATABASE_H
+
+#include <algorithm>
+#include <functional>
+
+#include <QFile>
+#include <QDataStream>
+#include <QVector>
+#include <QString>
+
+#include "../objects/profession.h"
+#include "../objects/user.h"
+
+typedef std::function<bool(User)> UserPredicat;
+
+class Database {
+private:
+    static Database *mInstance;
+    static const QString mFilename;
+
+    Database() = default;
+    QVector<Profession> mProfessions;
+    QVector<User> mUsers;
+
+    QVector<User*> findUserByPredicat(UserPredicat predicat);
+
+public:
+    static Database* instance();
+    QVector<Profession> professions() const;
+    QVector<User> users() const;
+
+    bool addUser(User usr);
+    User* getUser(UID uid);
+    User* getUser(QString login);
+    QVector<User*> getUsersByType(UserType type);
+    QVector<User*> getUsersByProfession(Profession prof);
+
+    Profession* getProfession(PID pid);
+
+    void save();
+    void load();
+};
+
+#endif // DATABASE_H
diff --git a/iFacility/iFacility.pro b/iFacility/iFacility.pro
index a31255d..b909493 100644
--- a/iFacility/iFacility.pro
+++ b/iFacility/iFacility.pro
@@ -13,13 +13,15 @@ SOURCES += \
     loginwindow.cpp \
     objects/profession.cpp \
     objects/user.cpp \
-    objects/userprofession.cpp
+    objects/userprofession.cpp \
+    db/database.cpp
 
 HEADERS += \
     loginwindow.h \
     objects/profession.h \
     objects/user.h \
-    objects/userprofession.h
+    objects/userprofession.h \
+    db/database.h
 
 FORMS += \
     loginwindow.ui
diff --git a/iFacility/objects/profession.h b/iFacility/objects/profession.h
index 05ff91a..08e1310 100644
--- a/iFacility/objects/profession.h
+++ b/iFacility/objects/profession.h
@@ -12,9 +12,9 @@ private:
     PID mPID;
     QString mTitle;
 
+public:
     Profession() = default;
 
-public:
     QString title() const;
     PID pID() const;