class UserDBHelper(ctx: Context) : ManagedSQLiteOpenHelper(ctx, DB_NAME, null, DB_VERSION) {

    companion object {
        const val DB_NAME = "DB_User"
        const val DB_VERSION = 1

        const val TABLE_USER = "table_User"

        const val CULM_ID = "id"
        const val CULM_NAME = "name"
        const val CULM_AGE = "age"

        private var instance: UserDBHelper? = null

        @Synchronized
        fun getInstance(ctx: Context): UserDBHelper {
            if (instance == null) {
                instance = UserDBHelper(ctx.getApplicationContext())
            }
            return instance!!
        }
    }

    override fun onCreate(db: SQLiteDatabase) {
        db.createTable(TABLE_USER, true,
                CULM_ID to INTEGER + PRIMARY_KEY + UNIQUE,
                CULM_NAME to TEXT,
                CULM_AGE to INTEGER)
    }

    override fun onUpgrade(db: SQLiteDatabase, oldVersion: Int, newVersion: Int) {
        db.dropTable(TABLE_USER, true)
    }
}