Earticle

SQLite는 모바일 장치, 내장형 장치 등 소형기기 또는 규모가 작은 환경에 적합하여 스마트 폰 앱, 내장형 소프트웨어 등에 널리 사용되는 오픈소스 데이터베이스 관리 시스템이다. 이 SQLite 는 소스 코드의 크기가 작아 소형 시스템에서도 잘 동작한다는 장점이 있지만, 반면에 제공하는 기 능에 여러 가지 제한이 있다는 문제점이 있다. 이런 제한 중의 하나로 SQLite은 트랜잭션을 데이터 베이스 단위로 동시성 제어를 하고 있어 여러 트랜잭션들이 함께 실행될 경우 성능이 낮아진다. 이 논문에서는 SQLite를 내장형 데이터베이스 시스템의 특성을 유지하면서도 트랜잭션의 동시성 제어 성능을 높이는 기능을 구현하였다. 이를 위해 락(lock) 관리 및 제어 작업에 관련된 오버헤드를 줄이 면서 동시성 제어를 할 수 있는 경량 락킹 기법(Very Lightweight Locking, VLL)을 활용하여 SQLite 데이터베이스 관리 시스템의 동시성제어 시스템을 개선하였다. 또 SQLite의 동세성 제어 단 위를 테이블 단위로 낮춰 트랜잭션의 동시성 제어 성능을 높이도록 구현하였다. 이 논문에서는 이렇 게 개발한 동시성 제어 기법의 구현 내용을 소개하고, 실험을 통해 구현한 동시성 제어 기법의 성능 을 비교.평가하였다.

SQLite is an open source database management system which has been widely used in smartphone apps and embedded software, because it is suitable for small-size environments such as mobile and embedded devices. While SQLite has the advantage running well on small embedded systems, it has several restrictions on its features. Of these restrictions, it uses the database unit as its locking granularity thus it suffers from poor performance when controling transactions concurrently. This paper implemented a new concurrency control mechanism of SQLite in order to provide with better performance of the concurrency control, with reserving the properties of embedded DBMSs. To achieve this goal, we adopt the Very Lightweight Locking (VLL) which can reduce the overhead of lock management and concurrent transaction control, and we extended the concurrency control method of SQLite based on the VLL method. We also implemented the concurrency control method with lesser locking granularity of the table unit in order to provide better performance. This paper describes the implementation details of the newly developed concurrency control mechanism and it also presents the performance evaluation of the method.

This paper presents the overview of the Android platform towards software development for mobile and non-mobile applications. Android platform includes the popular open source SQLite database which has been used with great success as on-disk file format that allows the developer to handle data in a simple way, but also have the use of database features (such as undo, redo, etc.).

This paper presents the concepts of database systems as well as the overview of the use of Unified Modeling Language (UML) as a standard notation of real-world objects in developing object-oriented design methodology for computer applications. The UML is a tool for specifying software systems that include standardized diagrams to define, illustrate and visually map or model a software system's design and structure. UML diagrams include the use case diagram, class diagram, sequence diagram, statechart diagram, activity diagram, component diagram, and deployment diagram. The integration of these diagrams to different software processes have been discussed.

In recent years, with the development of the information industry, we ushered in the age of big data, more and more Internet and mobile products are popping up. According to the mobile device is portable, real-time etc, the development of mobile phone system become the focus of scientific and technological development, but the research on its local database is relatively small. This paper introduced a query optimization method based on improved Particle Swarm Optimization algorithm (PSO) for SQLite database on Android platform. This method improves the original PSO, and put the database transaction into the Particle Swarm Optimization algorithm, and should be used to join query. It improves the speed of complex query, and optimizes the query on SQLite database. Experimental results show that this method is an effective way to optimize the SQLite database query, and also can be used in the Android platform.