sqlite3_iphone

1. 预备知识

读者需要有一定的SQLite数据库知识，懂得基本的SQL语句，掌握OSX系统terminal终端 以及 XCode编译器 的基本操作。

2. 创建数据库

打开 Applications-Utilities-Terminal，可见终端窗口。

假设当前系统用户为Smitty，可在终端窗口内键入如下命令：

cd /Users/Smitty/Documents

mkdir SQLiteDemo

cd SQLiteDemo

sqlite3 PersonDatabase.sql

至此，你已经在/Users/lookaflyingdonkey/Documents目录下创建了一个新的目录SQLiteDemo，并使用 sqlite3命令开启了SQLite终端，准备建立数据库结构并输入数据。

举例来说，若我们要建立的数据库表person需要有如下结构：唯一的id值，名字，职位描述，头像图片地址，那么下列命令将创建这个表，并添加几个人的纪录。

CREATE TABLE person (id INTEGER PRIMARY KEY, name VARCHAR(50), title TEXT, icon VARCHAR(255) );

INSERT INTO person (name, title, icon) VALUES('Peter','handy man','http://dblog.com.au/wp-content/elephant.jpg');

INSERT INTO person (name, title, icon) VALUES('Susan','manager','http://dblog.com.au/wp-content/monkey.jpg');

INSERT INTO person (name, title, icon) VALUES('Wilson','developer','http://dblog.com.au/wp-content/kangaroo.jpg');

执行完这几步后，可运行命令"SELECT * FROM person;"，检查数据库中是否已存在上面插入的数据。一旦确认一切正常，可用命令".quit"退出sqlite 命令行模式。

3. 创建项目

现在让我门创建Xcode项目。

首先在Xcode中选择创建一个新的” Navigation-Based Application“

输入项目名称"SQLiteDemo"，由于之前在同一位置创建了同名目录，Xcode将会询问是否覆盖已经存在的目录SQLiteDemo，选则是。这将使项目目录结构如下图所示。

4. 将SQLite框架和PersonDatabas数据库导入项目

首先我们需要将SQLite库引入项目。请右键点击左部菜单中的"Frameworks"目录，选择“Add > Existing Frameworks…”，

然后在本地目录中选择“/Developer/Platforms/iPhoneOS.platform/Developer /SDKs/iPhoneOS3.0.sdk/usr/lib/”，找到“libsqlite3.0.dylib”文件并双击。

一个弹出窗口将出现，点击其中“Add”按钮将库添加入项目中。

我们也需要将PersonDatabas 数据库导入Resources目录。请右键点击“Resources”目录，选择“Add > Existing Files…”，在本地目录中选择“/Users/Smitty/Documents/SQLiteDemo/”, 双击PersonDatabase.sql文件，点击弹出窗口中的“Add”按钮将其导入当前项目。

5. 开始编程

首先创建一个Person类。右键点击“Classes”目录，选择“Add > New File…”，在弹出窗口中选择“iPhone OS > Cocoa Touch Class > Objective-C class > NSObject” 并点击“Next”按钮。在下一窗口中，设置File Name为“Person.m”。点击“Finish”按钮完成创建。

修改Classes/Person.h为：

@interface Person : NSObject {

NSString *name;

NSString *title;

NSString *iconURL;

}

@property (nonatomic, retain) NSString *name;

@property (nonatomic, retain) NSString *title;

@property (nonatomic, retain) NSString *iconURL;

-(id)initWithName:(NSString *)n title:(NSString *)t url:(NSString *)u;

@end

修改Classes/Person.m为：

#import "Person.h"

@implementation Person

@synthesize name, title, iconURL;

-(id)initWithName:(NSString *)n title:(NSString *)t url:(NSString *)u {

self.name=n;

self.title=t;

self.iconURL=u;

return self;

}

@end

修改Other Sources/main.m为：

#import

#import "Person.h"

int main(int argc, char *argv[]) {

NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

//setup database name.

NSString *databaseName = @"PersonDatabase.sql";

// Get the path to the documents directory and append the databaseName

NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsDir = [documentPaths objectAtIndex:0];

NSString *databasePath = [documentsDirstringByAppendingPathComponent:databaseName];

// Create a FileManager object, we will use this to check the status

// of the database and to copy it over if required

NSFileManager *fileManager = [NSFileManager defaultManager];

// Check if the database has already been created in the users filesystem

BOOL success = [fileManager fileExistsAtPath:databasePath];

// If the database already exists then return without doing anything

if(!success){

// If not then proceed to copy the database from the application to the users filesystem

// Get the path to the database in the application package

NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:databaseName];

// Copy the database from the package to the users filesystem

[fileManager copyItemAtPath:databasePathFromApp toPath:databasePath error:nil];

}

// Query the database for all person records and construct the "person" array

sqlite3 *database;

// Init the animals Array

NSMutableArray *personArr = [[NSMutableArray alloc] init];

// Open the database from the users filessytem

if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK) {

// Setup the SQL Statement and compile it for faster access

const char *sqlStatement = "select * from person";

sqlite3_stmt *compiledStatement;

if(sqlite3_prepare_v2(database, sqlStatement, -1, &compiledStatement, NULL) == SQLITE_OK) {

// Loop through the results and add them to the feeds array

while(sqlite3_step(compiledStatement) == SQLITE_ROW) {

// Read the data from the result row

NSString *aName = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)];

NSString *aTitle = [NSString stringWithUTF8String:(char*)sqlite3_column_text(compiledStatement, 2)];

NSString *aIconUrl = [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 3)];

// Create a new animal object with the data from the database

Person *person = [[Person alloc] initWithName:aName title:aTitle url:aIconUrl];

// Add the animal object to the animals Array

[personArr addObject:person];

[person release];

}

}

// Release the compiled statement from memory

sqlite3_finalize(compiledStatement);

}

sqlite3_close(database);

for (Person *tmpPerson in personArr) {

NSLog(@"You can see %@ %@'s icon at %@", tmpPerson.title, tmpPerson.name, tmpPerson.iconURL);

[tmpPerson release];

}

NSLog(@"Done.");

[personArr release];

[fileManager release];

[pool release];

return (0);

}

6. 编译执行

完成修改后，运行“Build > Build and Run”, 关掉弹出的iPhone Simulator窗口，选择"Run > Console" 打开控制台，可看到如下输出信息。

参考：

http://www.cnblogs.com/AlexLiu/archive/2010/04/21/1716740.html