FMDB（数据库的操作）

#import "ViewController.h"

#import "FMDatabase.h"

//需要导入库FMDB 库文件libsqlite3.dylib

@interface ViewController ()<UINavigationControllerDelegate,UIImagePickerControllerDelegate>{

   IBOutlet UIImageView* _headView;

   IBOutlet UITextField* _nameField;

   IBOutlet UITextField* _desField;

   FMDatabase* _db;

}

//增 删 查 改

- (IBAction)add:(id)sender;

- (IBAction)del:(id)sender;

- (IBAction)fetch:(id)sender;

- (IBAction)update:(id)sender;

@end

@implementation ViewController

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    _headView.image = info[UIImagePickerControllerOriginalImage];

    [picker dismissViewControllerAnimated:YEScompletion:nil];

}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{

    [picker dismissViewControllerAnimated:YEScompletion:nil];

}

- (void)selectImage{

    UIImagePickerController* ipc = [[UIImagePickerControlleralloc] init];

    ipc.delegate =self;

    [selfpresentViewController:ipc animated:YEScompletion:nil];

}

- (void)viewDidLoad {

    [superviewDidLoad];

    

    UITapGestureRecognizer* tap = [[UITapGestureRecognizeralloc] initWithTarget:selfaction:@selector(selectImage)];

    [_headViewaddGestureRecognizer:tap];

    

    //数据库存在沙盒目录

    NSString* path = [NSStringstringWithFormat:@"%@/Documents/data.db",NSHomeDirectory()];

   NSLog(@"%@", path);

    //数据库操作类

   _db = [[FMDatabasealloc] initWithPath:path];

    //打开数据库

   BOOL res = [_dbopen];

    //[_db close];

   if (res == NO) {

       NSLog(@"数据库打开失败");

       return;

    }

    //创建一个表

    res = [_dbexecuteUpdate:@"create table if not exists USER(uid integer primary key autoincrement, name, des, image)"];

   if (res == NO) {

       NSLog(@"创建表失败");

    }

}

- (void)add:(id)sender{

    //添加一条数据

    //NSString, NSNumber, NSData

   if (_nameField.text ==nil || _desField.text ==nil || _headView.image ==nil) {

       return;

    }

    NSData* data =UIImagePNGRepresentation(_headView.image);

    //插入数据

    BOOL res = [_dbexecuteUpdate:@"insert into USER(name,des,image) values(?,?,?)",_nameField.text,_desField.text, data];

   if (res == NO) {

       NSLog(@"插入数据失败");

    }

    _nameField.text =@"";

   _desField.text =@"";

   _headView.image =nil;

}

//删除

- (void)del:(id)sender{

    BOOL res = [_dbexecuteUpdate:@"delete from USER where name=?",_nameField.text];

   if (res == NO) {

       NSLog(@"删除失败");

    }

}

//查询

- (void)fetch:(id)sender{

    FMResultSet* set = [_dbexecuteQuery:@"select * from USER"];

   /*

     id name  des image

     1 曹操   魏王

     2 曹仁   大将

     3 曹洪   大将

     4 夏侯惇  大将

     */

    //每次遍历，指针向下走一行，我们通过列数取值

   while ([set next]) {

       int uid = [set intForColumn:@"uid"];

        //[set objectForColumnName:@"float"];

       NSString* name = [set stringForColumn:@"name"];

       NSString* des = [set stringForColumn:@"des"];

       NSData* data = [set dataForColumn:@"image"];

       NSLog(@"%d-%@",uid, name);

    }

}

- (void)update:(id)sender{

}