iPhone开发数据持久化总结之第4篇—sqlite3数据库 .
转载请注明出处，原文网址：http://blog.csdn.net/m_changgong/article/details/8284135 作者：张燕广


实现的功能：1）演示使用sqlite3持久化数据。

关键词：数据持久化 sqlite3 数据库




1、将上一篇iPhone开发【二十二】数据持久化总结之第3篇归档（NSKeyedArchiver、NSKeyedUnarchiver）的工程拷贝一份，名称修改为Persistence-sqlite，工程结构如下：
[img]

[/img]
Person类已经没用了，可以删掉。








2、为工程添加sqlite3的库libsqlite3.dylib，如下图所示：
[img]

[/img]






3、主要修改了ViewController类，ViewController.h如下：

#define kFileName @"archive"
#define kDataKey @"Data"
#define kSqliteFileName @"data.db3"

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController
@property(nonatomic,retain)IBOutlet UITextField *name;
@property(nonatomic,retain)IBOutlet UITextField *gender;
@property(nonatomic,retain)IBOutlet UITextField *age;
@property(nonatomic,retain)IBOutlet UITextField *education;

-(NSString *)dataFilePath;
-(void)applicationWillResignActive:(NSNotification *)nofication;

@end

ViewController.m如下：

#import "ViewController.h"
#import "Person.h"
#import <sqlite3.h>

@implementation ViewController
@synthesize name,gender,age,education;

-(NSString *)dataFilePath{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    //return [documentsDirectory stringByAppendingPathComponent:kFileName];
    return [documentsDirectory stringByAppendingPathComponent:kSqliteFileName];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
	// Do any additional setup after loading the view, typically from a nib.
    NSString *filePath = [self dataFilePath];
    NSLog(@"filePath=%@",filePath);
    
    if([[NSFileManager defaultManager] fileExistsAtPath:filePath]){
        //属性列表
        /*
        NSArray *array = [[NSArray alloc]initWithContentsOfFile:filePath];
        name.text = [array objectAtIndex:0];
        gender.text = [array objectAtIndex:1];
        age.text = [array objectAtIndex:2];
        education.text = [array objectAtIndex:3];
        
        [array release];*/
        
        //归档
        /*
        NSData *data = [[NSMutableData alloc]initWithContentsOfFile:[self dataFilePath]];
        NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc]initForReadingWithData:data];
        Person *person = [unarchiver decodeObjectForKey:kDataKey];
        [unarchiver finishDecoding];
        
        name.text = person.name;
        gender.text = person.gender;
        age.text = person.age;
        education.text = person.education;
        
        [unarchiver release];
        [data release];*/
        
        //sqlite3
        sqlite3 *database;
        //打开数据库
        if(sqlite3_open([filePath UTF8String], &database)!=SQLITE_OK){//备注1
            //数据库打开失败，关闭数据库
            sqlite3_close(database);
            NSAssert(0,@"打开数据库失败");
        }
        
        char* errorMsg;
        NSString *createSQL = @"CREATE TABLE IF NOT EXISTS PERSON (name TEXT PRIMARY KEY,gender TEXT,age TEXT,education TEXT);";
        //创建表
        if(sqlite3_exec(database, [createSQL UTF8String], NULL, NULL, &errorMsg)!=SQLITE_OK){//备注2
            //创建表失败，关闭数据库
            sqlite3_close(database);
            NSAssert1(0, @"创建表失败：%s", errorMsg);
        }
        
        //查询表
        NSString *querySQL = @"SELECT name,gender,age,education FROM PERSON ORDER BY name";

        //执行查询，遍历查询结果
        sqlite3_stmt *statment;
        if(sqlite3_prepare_v2(database, [querySQL UTF8String], -1, &