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