1.FMDB简单介绍

iOS中原生的SQLite API在使用上相当不友好，在使用时，非常不便。于是，就出现了一系列将SQLite API进行封装的库FMDB (https://github.com/ccgus/fmdb) 是一款简洁、易用的封装库

FMDB同时兼容ARC和非ARC工程，会自动根据工程配置来调整相关的内存管理代码。

FMDB常用类：
FMDatabase ：一个单一的SQLite数据库，用于执行SQL语句。
FMResultSet ：执行查询一个FMDatabase结果集。 FMDatabaseQueue ：在多个线程来执行查询和更新时会使用这个类。
创建数据库：
db = [FMDatabase databaseWithPath:database_path];

● FMDB优点：

1.使用起来更加面向对象，省去了很多麻烦、冗余的C语言代码
2.对比苹果自带的CoreData框架，更加轻量级和灵活
3.提供多线程安全，有效地防止数据混乱，原来的SQLite不是线程安全的

● FMDB缺点：
因为是OC语言封装的，失去了SQLite原来的跨平台性(相对于其他语言)

2.效果图

Untitled2.gif

3.注意点

1.使用cocoapods
或者去下载FMDBsdk拖进工程中
2.须导入libsqlite3.0.tbd依赖库

4.代码展示

1.创建模型用于接受数据

import "model.h"

//分类
@property(nonatomic,strong) NSString *classify;
//书名
@property(nonatomic,strong) NSString *bookName;
//价格
@property(nonatomic,strong) NSString *bookPrice;
//作者
@property(nonatomic,strong) NSString *bookAuthor;
//备注
@property(nonatomic,strong) NSString *remark;
//id
@property(nonatomic,assign) NSInteger bookID;

2.创建业务处理层用于处理数据
.h

#import "FMDatabase.h"
#import "model.h"

@interface loadData : NSObject
//单例
+(instancetype)shareLoadData;
//添加
-(void)addBook:(model *)mode;
//查询
-(NSMutableArray *)marr;
//修改
-(void)changeBook:(model *)model;
//删除
-(void)deleteBook:(model *)model;

#import "loadData.h"
static loadData *ld =nil;
static FMDatabase *fate;
@implementation loadData
//单例
+(instancetype)shareLoadData
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        ld = [[loadData alloc]init];
        [ld initA];
    });
    return ld;
}
+(instancetype)allocWithZone:(struct _NSZone *)zone
{
    if (!ld) {
        ld = [super allocWithZone:zone];
    }
    return ld;
}
-(id)copy
{
    return self;
}
-(id)mutableCopy
{
    return self;
}
//初始化数据库
-(void)initA{
    //创建沙盒
    NSString *Ste = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES)objectAtIndex:0];
    //定义文件名
    NSString *path = [Ste stringByAppendingPathComponent:@"HousingInfo.sqlite"];
    //初始化
    fate = [[FMDatabase alloc]initWithPath:path];
    //判断
    if ([fate open]) {
        //初始化
        [fate executeUpdate:@"create table class (bookID integer primary key, classify text, bookName text , bookPrice text , bookAuthor text , remark text)"];
        [fate close];
        NSLog(@"成功");
    }else{
        NSLog(@"失败");
    }
}
//添加
-(void)addBook:(model *)mode
{

    
    BOOL isc = false;
    NSArray *arr = [self marr];
    for (model *m in arr) {
        if ([m.classify isEqualToString:mode.classify] && [m.bookName isEqualToString:mode.bookName]&&[m.bookPrice isEqualToString:mode.bookPrice]&&[m.bookAuthor isEqualToString:mode.bookAuthor]&&[m.remark isEqualToString:mode.remark]) {
            isc = true;
        }
    }
    if (isc) {
        NSLog(@"数据相同");
    }else{
        [fate open];
        BOOL isb = [fate executeUpdate:[NSString stringWithFormat:@"insert into class values (null , '%@','%@','%@','%@','%@')",mode.classify,mode.bookName,mode.bookPrice,mode.bookAuthor,mode.remark]];
        if (isb) {
            NSLog(@"添加成功");
        }else{
            NSLog(@"添加失败");
        }
        [fate close];
}
//查询
-(NSMutableArray *)marr
{
    //初始化
    NSMutableArray *marr = [NSMutableArray new];
    //开始
    [fate open];
    //初始化
    FMResultSet *Set = [[FMResultSet alloc]init];
    //使用set接受
    Set = [fate executeQuery:@"select *from class"];
    //判断
    while ([Set next]) {
        //初始化
        model *mm = [model new];
        //链接
        mm.classify = [Set stringForColumn:@"classify"];
        mm.bookName = [Set stringForColumn:@"bookName"];
        mm.bookPrice = [Set stringForColumn:@"bookPrice"];
        mm.bookAuthor = [Set stringForColumn:@"bookAuthor"];
        mm.remark = [Set stringForColumn:@"remark"];
        mm.bookID = [Set intForColumn:@"bookID"];
        //添加到数组
        [marr addObject:mm];
        
    }
    //关闭
    [fate close];
    //返回值
    return marr;
}
//修改
-(void)changeBook:(model *)model
{
    //开始
    [fate open];
    //初始化
    NSString *str = [NSString stringWithFormat:@"update class set classify = '%@',bookName = '%@',bookPrice = '%@',bookAuthor = '%@',remark = '%@' where bookID = '%ld'",model.classify,model.bookName,model.bookPrice,model.bookAuthor,model.remark,model.bookID];
    //BOOL值接受
    BOOL ii = [fate executeUpdate:str];
    //判断
    if (ii) {
        NSLog(@"成功");
    }else{
        NSLog(@"失败");
    }
    //关闭
    [fate close];
}
//删除
-(void)deleteBook:(model *)model
{
    //开始
    [fate open];
    //初始化
    NSString *str = [NSString stringWithFormat:@"delete from class where bookID = '%ld' ",model.bookID];
    //BOOL值接受
    BOOL ii = [fate executeUpdate:str];
    //判断
    if (ii) {
        NSLog(@"成功");
    }else{
        NSLog(@"失败");
    }
    //关闭
    [fate close];
}
@end

3.数据进行展示

//将要显示
-(void)viewWillAppear:(BOOL)animated{
    //查询
    Marr = [[loadData shareLoadData]marr];
    //刷新
    [tabele reloadData ];//这个是展示在表格中的
}

4.数据添加页面

#import "model.h"
#import "loadData.h"
@interface addViewController ()
@property (weak, nonatomic) IBOutlet UITextField *classiftyTF;
@property (weak, nonatomic) IBOutlet UITextField *bookNameTF;
@property (weak, nonatomic) IBOutlet UITextField *bookAuthorTF;
@property (weak, nonatomic) IBOutlet UITextField *bookpriceTF;
@property (weak, nonatomic) IBOutlet UITextField *remarkTF;

@end

@implementation addViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
}
- (IBAction)add:(id)sender {
    //初始化
    model *mm = [model new];
    //链接
    mm.classify =self.classiftyTF.text;
    mm.bookName =self.bookNameTF.text;
    mm.bookPrice =self.bookpriceTF.text;
    mm.bookAuthor =self.bookpriceTF.text;
    mm.remark =self.remarkTF.text;
    
    //添加到数据库
    [[loadData shareLoadData]addBook:mm];
    //跳转
    [self.navigationController popViewControllerAnimated:YES];
}

5.数据修改界面

从原界面到修改界面有一步传值操作（属性传值）

#import "model.h"
#import "loadData.h"
@interface changeViewController ()
@property (weak, nonatomic) IBOutlet UITextField *classityTF;
@property (weak, nonatomic) IBOutlet UITextField *bookAuthorTF;
@property (weak, nonatomic) IBOutlet UITextField *bookPriceTF;
@property (weak, nonatomic) IBOutlet UITextField *bookNameTF;
@property (weak, nonatomic) IBOutlet UITextField *remarkTF;

@end

@implementation changeViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    //将数据添加到修改页面
    self.classityTF.text =self.mm.classify;
    self.bookNameTF.text =self.mm.bookName;
    self.bookPriceTF.text =self.mm.bookPrice;
    self.bookAuthorTF.text =self.mm.bookAuthor;
    self.remarkTF.text =self.mm.remark;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (IBAction)change:(id)sender {
    //初始化
    model *mm = self.mm;
    //链接
    mm.classify = self.classityTF.text;
    mm.bookName = self.bookNameTF.text;
    mm.bookPrice = self.bookPriceTF.text;
    mm.bookAuthor = self.bookAuthorTF.text;
    mm.remark = self.remarkTF.text;
    //添加
    [[loadData shareLoadData]changeBook:mm];
    //跳转
    [self.navigationController popViewControllerAnimated:YES];
}

FMDB的简单使用