FMDB 排它锁

 -------------------------------------基本操作-------------------------------------

 

#import "ViewController.h"

 

#import "FMDB.h"

@interface ViewController ()

@property (nonatomic,strong)FMDatabase *dataBase;

@end


@implementation ViewController

- (IBAction)insertData:(id)sender {

    

    //3.增加 数据 (100条 数据随机)

    for (int i = 0; i <100; i++) {

        

        NSString *strName = [NSString stringWithFormat:@"8mingyeuxin-%d",i];

        

        NSString *sqlStr = [NSString stringWithFormat:@"INSERT INTO t_student (name ,score)VALUES('%@',%.02f)",strName,arc4random_uniform(1000)/10.0];

        

        //执行 //非查询语句  执行的方法

        BOOL success =  [self.dataBase executeUpdate:sqlStr];

        if (success) {

            NSLog(@"添加成功!");

        }else{

            NSLog(@"添加失败!");

        }

        

    }

    

    

}

- (IBAction)selectData:(id)sender {

    

    NSString *strSql =  @"SELECT * FROM t_student WHERE score > 60.0 ORDER BY score DESC;";

    //查询语句 执行的方法

    FMResultSet *set =  [self.dataBase executeQuery:strSql];


    while ([set next]) {

        //name

        //NSString *name = [set stringForColumnIndex:1];

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

        //score

        CGFloat score = [set doubleForColumn:@"score"];

        

        NSLog(@"name = %@  score = %f",name,score);

    }

 

}


- (void)viewDidLoad {

    [super viewDidLoad];

    //1.创建数据库

    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject]stringByAppendingPathComponent:@"student"];

    FMDatabase *dataBase = [FMDatabase databaseWithPath:path];

    self.dataBase = dataBase;

    

    BOOL success = [dataBase open];

    if (success) {

        NSLog(@"数据库创建成功!");

        //2.创建表

        NSString *str = @"CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, score REAL NOT NULL)";

        if ([self.dataBase executeUpdate:str]) {

            NSLog(@"表创建成功!");

        }else{

            NSLog(@"创建表失败!");

        }

    }else{

        NSLog(@"数据库创建失败!");

    }


}



@end

 

 

 

 

 

 

-------------------------------------原子操作-------------------------------------

#import "ViewController.h"

#import "FMDB.h"

@interface ViewController ()

@property (nonatomic,strong)FMDatabaseQueue *dataBaseQ;

@end


@implementation ViewController

//线程安全 公共资源 A使用 的时候 B不能使用


//int a = 110;

//

//100 - 90;

//A  a = 10;

//

//排队等待:

//10 + 100

//

//B  a = 110;


- (IBAction)insertData:(id)sender {

   

    [self.dataBaseQ inDatabase:^(FMDatabase *db) {

        //3.增加 数据 (100条 数据随机)

        for (int i = 0; i <100; i++) {

            

            NSString *strName = [NSString stringWithFormat:@"8mingyeuxin-%d",i];

            

            NSString *sqlStr = [NSString stringWithFormat:@"INSERT INTO t_student (name ,score)VALUES('%@',%.02f)",strName,arc4random_uniform(1000)/10.0];

            

            //执行 //非查询语句  执行的方法

            BOOL success =  [db executeUpdate:sqlStr];

            if (success) {

                NSLog(@"添加成功!");

            }else{

                NSLog(@"添加失败!");

            }

            

        }


    }];

    

}

- (IBAction)selectData:(id)sender {

    [self.dataBaseQ inDatabase:^(FMDatabase *db) {

       

        NSString *strSql =  @"SELECT * FROM t_student WHERE score > 60.0 ORDER BY score DESC;";

        //查询语句  执行的方法

        FMResultSet *set =  [db executeQuery:strSql];

        

        while ([set next]) {

            //name

            //NSString *name = [set stringForColumnIndex:1];

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

            //score

            CGFloat score = [set doubleForColumn:@"score"];

            

            NSLog(@"name = %@  score = %f",name,score);

        }


        

    }];

    

}


- (void)viewDidLoad {

    [super viewDidLoad];

    

    //打开数据库 如果没有就创建

    NSString *path = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)lastObject]stringByAppendingPathComponent:@"data.sqlite"];

    //创建数据库的队列

    FMDatabaseQueue *dataBaseQ = [FMDatabaseQueue databaseQueueWithPath:path];

    self.dataBaseQ = dataBaseQ;

    [dataBaseQ inDatabase:^(FMDatabase *db) {

       

        BOOL success = [db open];

        if (success) {

            NSLog(@"数据库创建成功!");

            //2.创建表

            NSString *str = @"CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, score REAL NOT NULL)";

            if ([db executeUpdate:str]) {

                NSLog(@"表创建成功!");

            }else{

                NSLog(@"创建表失败!");

            }

        }else{

            NSLog(@"数据库创建失败!");

        }


    }];

}


- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

    // Dispose of any resources that can be recreated.

}


@end

 

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