SQLite

SQLite ( or ) is a relational database management system contained in a C programming library. In contrast to other database management systems, SQLite is not a separate process that is accessed from the client application, but an integral part of it.
SQLite is ACID-compliant and implements most of the SQL standard, using a dynamically and weakly typed SQL syntax that does not guarantee the domain integrity.
SQLite is a popular choice as embedded database for local/client storage in application software such as web browsers. It is arguably the most widely deployed database engine, as it is used today by several widespread browsers, operating systems, and embedded systems, among others. SQLite has many bindings to programming languages.
The source code for SQLite is in the public domain.
== Design ==
Unlike client–server database management systems, the SQLite engine has no standalone processes with which the application program communicates. Instead, the SQLite library is linked in and thus becomes an integral part of the application program. (In this, SQLite follows the precedent of Informix SE of c. 1984) The library can also be called dynamically. The application program uses SQLite's functionality through simple function calls, which reduce latency in database access: function calls within a single process are more efficient than inter-process communication. SQLite stores the entire database (definitions, tables, indices, and the data itself) as a single cross-platform file on a host machine. It implements this simple design by locking the entire database file during writing. SQLite read operations can be multitasked, though writes can only be performed sequentially.
== History ==
D. Richard Hipp designed SQLite in the spring of 2000 while working for General Dynamics on contract with the United States Navy. Hipp was designing software used on board guided missile destroyers, which were originally based on HP-UX with an IBM Informix database back-end. The design goals of SQLite were to allow the program to be operated without installing a database management system or requiring a database administrator. In August 2000, version 1.0 of SQLite was released, based on gdbm (GNU Database Manager). SQLite 2.0 replaced gdbm with a custom B-tree implementation, adding support for transactions. SQLite 3.0, partially funded by America Online, added internationalization, manifest typing, and other major improvements.
In 2011 Hipp announced his plans to add an UnQL interface to SQLite databases and to develop UnQLite, an embeddable document-oriented database. Howard Chu ported SQLite 3.7.7.1 to use Openldap MDB instead of the original Btree code and called it sqlightning. One test of inserting 1000 records was 20 times faster.MDB: A Memory-Mapped Database and Backend for OpenLDAP, Howard Chu, [MDB: A Memory-Mapped Database and Backend for OpenLDAP LDAPCon 2011].sqlightning source code.
== Features ==
SQLite implements most of the SQL-92 standard for SQL but it lacks some features. For example it has partial support for triggers, and it can't write to views (however it supports INSTEAD OF triggers that provide this functionality). While it supports complex queries, it still has limited ALTER TABLE support, as it can't modify or delete columns.
SQLite uses an unusual type system for an SQL-compatible DBMS; instead of assigning a type to a column as in most SQL database systems, types are assigned to individual values; in language terms it is dynamically typed. Moreover, it is weakly typed in some of the same ways that Perl is: one can insert a string into an integer column (although SQLite will try to convert the string to an integer first, if the column's preferred type is integer). This adds flexibility to columns, especially when bound to a dynamically typed scripting language. However, the technique is not portable to other SQL products. A common criticism is that SQLite's type system lacks the data integrity mechanism provided by statically typed columns in other products. The SQLite web site describes a "strict affinity" mode, but this feature has not yet been added. However, it can be implemented with constraints like CHECK(typeof(x)='integer').
Several computer processes or threads may access the same database concurrently. Several read accesses can be satisfied in parallel. A write access can only be satisfied if no other accesses are currently being serviced. Otherwise, the write access fails with an error code (or can automatically be retried until a configurable timeout expires). This concurrent access situation would change when dealing with temporary tables. This restriction is relaxed in version 3.7 when write-ahead logging (WAL) is turned on enabling concurrent reads and writes.
A standalone program called sqlite3 is provided that can be used to create a database, define tables within it, insert and change rows, run queries and manage an SQLite database file. This program is a single executable file on the host machine. It also serves as an example for writing applications that use the SQLite library.
SQLite full Unicode support is optional.
SQLite has automated regression testing prior to each release. Over 2 million tests are run as part of a release's verification. Starting with the August 10, 2009 release of SQLite 3.6.17, SQLite releases have 100% branch test coverage, one of the components of code coverage.
As of version 3.8.2 it's possible to create tables without rowid.ReleaseLog SQLite.org, visited 8th December 2013
== Development ==
SQLite development stores revisions of its source code in Fossil, a distributed version control system that is itself built upon an SQLite database.
== Adoption ==
=== Programming languages ===
SQLite has bindings for a large number of programming languages, including :
* BASIC
* Delphi
* C
* C#
* C++
* Clipper//Harbour
* Common Lisp
* Curl
* D
* Free Pascal
* Go
* Haskell
* Java
* JavaScriptJSPDO JavaScript database access abstraction API 
* Livecode
* Lua
* newLisp
* Objective-C (on OS X and iOS)
* OCaml
* PerlDBD::SQLite: Perl DBI Interface to SQLite
* PHP
* Pike
* PureBasic
* PythonPySQLite: Python bindings for SQLite
* R
* REALbasic
* REBOL
* RubySQLite/Ruby: Ruby bindings for SQLite
* Scheme
* Smalltalk
* Tcl
* Visual Basic
=== Middleware ===
* ADO.NET adapter, initially developed by Robert Simpson, is maintained jointly with the SQLite developers since April 2010.http://system.data.sqlite.org/index.html/doc/trunk/www/index.wiki
* ODBC driver has been developed and is maintained separately by Christian Werner.http://www.ch-werner.de/sqliteodbc/ Werner's ODBC driver is the recommended connection method for accessing SQLite from OpenOffice.org.http://documentation.openoffice.org/HOW_TO/data_source/SQLite.pdf
* COM (ActiveX) wrapper making SQLite accessible on Windows to scripted languages such as JScript and VBScript. This adds database capabilities to HTML Applications (HTA).
* XULRunner uses SQLite
=== Web browsers ===
* The browsers Google Chrome, Opera, Safari and the Android Browser all allow for storing information in, and retrieving it from, a SQLite database within the browser, using the Web SQL Database technology.
* Mozilla Firefox and Mozilla Thunderbird store a variety of configuration data (bookmarks, cookies, contacts etc.) in internally managed SQLite databases, and even offer an add-on to manage SQLite databases.
=== Web application frameworks ===
* Django, a Python web framework, supports SQLite3 by default.
* As of version 7, Drupal, a PHP-based content management system for making websites and blogs, has an option to install using SQLite.
* Ruby on Rails' default database management system is also SQLite.
* web2py, a Python web framework, default database management system is also SQLite.
=== Various ===
* Skype is a widely deployed application that uses SQLite.
* Adobe Systems uses SQLite as its file format in Adobe Photoshop Lightroom, a standard database in Adobe AIR, and internally within Adobe Reader.
* The Service Management Facility, used for service management within the Solaris and OpenSolaris operating systems, uses SQLite internally.
* Flame, a malware program used for cyberespionage, used SQLite to store the data it collects.
* The Xojo Programming Language has SQLite support built in to both the desktop and web frameworks.
=== Operating systems ===
Because of its small size, SQLite is well suited to embedded systems, and is also included in:
* Blackberry's BlackBerry 10 OS
* Microsoft's Windows Phone 8
* Apple's iOS
* Symbian OS
* Nokia's Maemo
* Google's Android
* Linux Foundation's MeeGo
* LG's webOS
* NetBSD
* OpenBSD
* FreeBSD where starting with 10-RELEASE version it is the core package management system.
However, it is also suitable for desktop operating systems; Apple adopted it as an option in OS X's Core Data API from the original implementation in Mac OS X 10.4 onwards, and also for administration of videos and songs on the iPhone.
== See also ==
* Comparison of relational database management systems
* List of relational database management systems
* Flat file database
* SQLite-related tools:
** SQLite Manager
** SpatiaLite
** SQLite Database Browser (multi-platform)
** SQLite Database Browser New (multi-platform)
** SQLiteMan (multi-platform)
** SQLiteStudio (multi-platform)
** SQLite Administrator (Windows only)
** SQLite Expert (Windows only)
** SQLite Professional (OS X only)
** Android SQLite Manager (Android only)
** kbmSQLiteMan (Windows only) Free (register to download) Simple to use, supports SQLite 3.8+
* Similar database engines:
** SQL Server Compact
** H2 (DBMS)
** Berkeley DB
== Citations ==
== References ==
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== External links ==
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SQLite는 MySQL나 PostgreSQL와 같은 데이터베이스 관리 시스템이지만, 서버가 아니라 응용 프로그램에 넣어 사용하는 비교적 가벼운 데이터베이스이다.
영어권에서는 '에스큐엘라이트(<)'
또는 '시퀄라이트()'라고 읽는다.
일반적인 RDBMS에 비해 대규모 작업에는 적합하지 않지만, 중소 규모라면 속도에 손색이 없다.
또 API는 단순히 라이브러리를 호출하는 것만 있으며, 데이터를 저장하는 데 하나의 파일만을 사용하는 것이 특징이다. 버전 3.3.8에서는 풀텍스트 검색 기능을 가진 FTS1 모듈이 지원된다. 컬럼을 삭제하거나 변경하는 것 등이 제한된다.
구글 안드로이드 운영 체제에 기본 탑재된 데이터베이스이기도 하다.
== 주석 ==
== 같이 보기 ==
* RDBMS 비교
* RDBMS 목록
* SQL 서버 컴팩트
* SQLite 관리자
* H2
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