SQLite 3
Scott MacVicar
PHP Barcelona 2008

Who Am I?
• Employed by Jelsoft Enterprises Ltd
• PHP (SQLite3, imagick, svn)
• GD

Overview
• What is SQLite?
• Why use SQLite?
• Who uses SQLite?
• SQLite Explained
• Difference between SQLite 2 and 3
• PDO / SQLite3

What is SQLite?
• Embedded SQL Database Engine
• Serverless - accesses disk directly
• Single file
• Cross Platform / Architecture
• Small footprint
• Manifest typing

Why use SQLite?
• Zero Configuration
• Portable
• Public Domain

Public Domain?
May you do good and not evil.
May you find forgiveness for yourself and forgive others.
May you share freely, never taking more than you give.

¿Public Domain?

Big SQLite Users
• Lightroom
• AIR
sqlite3 ~/Pictures/Lightroom/Lightroom\\ Library.aglib

Big SQLite Users
• Mail
• Safari
• Aperture
• Core Data
• iPhone
sqlite3 ~/Library/Mail/Envelope\\ Index
sqlite3 ~/Library/Caches/com.apple.Safari/Cache.db
sqlite3 ~/Pictures/Aperture Library.aplibrary/Aperture.aplib

Big SQLite Users
• Gears
• Android

Big SQLite Users
• Virus Information

Big SQLite Users
• History
• Bookmarks
• Downloads

Big SQLite Users
• Metadata

Where can SQLite be used?
• Replacement for a custom file format
• Temporary data storage (Unit Tests) - :memory:
• Alternative to enterprise DB for demo
• Local node storage
• Communication between apps
• Embedded Devices

Versions
• SQLite - 2.8.17
• PDO - 3.3.7 + 2.8.17 (3.6.2 in PHP 5.3)
• SQLite3 - 3.6.2, minimum is 3.3.9

SQLite 3
• 64-bit Rowids • Connections shared
between threads
• BLOB support
• Runtime loadable
• Improved concurrency extensions
• UTF-16 / UTF-8 • Fulltext searching
• User defined collations • ICU support
• Named bound • OS Interface
parameters

SQLite v2
• Smaller subset of SQL supported
• Larger file format
• Database format incompatible with v3
• No Unicode support
• No reading while writing

Examples
• Firefox 3.0
• Profile directory contains places.sqlite
• Schema on the next page
• iPhone SMS

Firefox Places Schema

PDO

SQLite3

Live Demo (Hopefully)

iPhone SMS Schema
/private/var/root/Library/SMS/sms.db
~/Library/Application Support/MobileSync/Backup

Custom Functions
• Define SQL Functions in PHP
• Implement missing features
• Aggregation functions

Function Example

Custom Collations
• Sorting in alphabetical ☹ ☺
order
a a
• ICU also provides this i é
functionality
u i
• Use createCollation to é ó
define comparison ó u
function

Fulltext Indexing

Fulltext Searching

SQLite3 Extension
SQLite3 SQLite3Stmt
open paramCount
close close
exec execute
version reset
lastInsertRowID clear
loadExtension bindValue
escapeString bindParam
prepare
query
createFunction
createAggregate
lastErrorMsg

SQLite3 Extension
SQLite3Result
fetchArray
reset
finalize
columnType
columnName
numColumns

Improving Performance
• Pragma
• cache_size
• fullfsync
• synchronous
• Shared Cache
• Use Transactions

Benchmarks
• Dual Xeon 3.2GHz,
2GB RAM, Centos 5
• MySQL vs SQLite
• Synthetic Benchmark -
YMMV
Original Image by Ben McLeod

Benchmarks - Tests
• 15 tests
• INSERT
• SELECT
• UPDATE
• DELETE
• DROP

Benchmarks - Insert
MySQL
10.0 SQLite 2
SQLite 3
7.5 SQLite 3 (nosync)
5.0
2.5
0
Test 1 Test 2

Benchmarks - Select
MySQL
10.0 SQLite 2
SQLite 3
7.5 SQLite 3 (nosync)
5.0
2.5
0
Test 3 Test 4

Benchmarks - Indices
MySQL
1.2 SQLite 2
SQLite 3
0.9 SQLite 3 (nosync)
0.6
0.3
0
Test 5 Test 6

Benchmarks - Update
MySQL
5.00 SQLite 2
SQLite 3
3.75 SQLite 3 (nosync)
2.50
1.25
0
Test 7 Test 8 Test 9

Benchmarks - Delete
MySQL
2.0 SQLite 2
SQLite 3
1.6
SQLite 3 (nosync)
1.2
0.8
0.4
0
Test 11 Test 12 Test 13 Test 14

Benchmarks - Summary
• SQLite 3 is faster in almost every test
• Using MyISAM would show faster results
• Doesn’t test concurrency

Converting from MySQL
• varchar, char -> text
• smallint, tinyint, int -> integer
• auto_increment -> autoincrement
• unknown types converted to text
• MySQLi functions have SQLite3 equivalents

Unsupported SQL - Examples
Original Image by Clive Arundell

Limitations
• Very large datasets
• High concurrency
• No Foreign Keys
• Nested Transactions
• Writing to Views

Miscellaneous
• Integrity Check
• Reclaim Unused Space
• Backup

Tools - SQLite Manager

Resources
• http://www.sqlite.org
• http://www.php.net/sqlite3
• http://pecl.php.net/sqlite3
• http://talks.macvicar.net
• https://addons.mozilla.org/en-US/firefox/
addon/5817