数据存储之第三方FMDB

//
//  ViewController.m
//  FMDBDemo
//
//  Created by cyw on 15-4-26.
//  Copyright (c) 2015年 cyw. All rights reserved.
//

#import "ViewController.h"
#import "FMDB.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
//    FMDB常用三个类:
//    1.FMDatabase :单一的sqlite数据库，用于执行sql语句
//    2.FMDatabaseQueue:多线程下执行sql语句
//    3.FMResultSet:sql语句的结果集
    
//    1.数据库文件路径
    NSString *path=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString *filePath=[path stringByAppendingPathComponent:@"cyw.sqlite"];
    NSLog(@"%@",filePath);
    
//    创建FMDB对象
//    参数有3中情况:
//    1.文件路径 文件不存在自动创建
//    2.nil 会创建内存中的临时数据库，当FMDatabase关闭时，自动销毁
//    3.@"" 会在临时目录创建空数据库，关闭时销毁
//    FMDatabase *db=[[FMDatabase alloc]initWithPath:filePath];
//    FMDatabase *bd=[FMDatabase databaseWithPath:filePath];
    
    //打开数据库
//    if ([db open]) {
//         //新建数据库
//        [self createTable:db];
//        
//         //插入数据
//        [self insertData:db];
//        //查询数据
//        [self selectData:db];
//        [db close];
//    }
//    数据库有锁和事务,在FMDB中可以用FMDatabaseQueue来实现
//    锁主要解决多线程的问题 事务算是加了一个隐式锁
    //创建数据库队列
    FMDatabaseQueue *queue=[FMDatabaseQueue databaseQueueWithPath:filePath];
//    [self queueSelect:queue];
//    [self queueTransaction:queue];
    [self queueIntranscation:queue];
    
    
}
-(BOOL)createTable:(FMDatabase*)db
{
    //此两个sql一起执行报错
    //create table if not exists P_Class (CId integer primary key ,CName varchar(20));
    NSString *strsql=@"create table if not exists Person(id integer primary key autoincrement ,age integer not null,name text not null,photo blob,registerTime DATETIME DEFAULT (datetime(CURRENT_TIMESTAMP,‘localtime‘)),sex char(1) default ‘0‘,money numeric(10,2),classId integer,constraint fk_Person_class foreign key (classId) references P_Class (CId));";
//    FMDatabase中更新操作都是使用executeUpdate方法 查询使用executeQuery方法
   BOOL result= [db executeUpdate:strsql];
    if (result) {
        NSLog(@"数据库创建成功");
    }
    else
    {
        NSLog(@"数据库创建失败");
    }
    return result;
}
-(void)insertData:(FMDatabase*)db
{
    [db executeUpdate:@"delete from person"];
    //executeUpdate方法的不同参数
//   [db executeUpdate:@"insert into P_Class(CId,CName) values(?,?);" withArgumentsInArray:@[@1001,@"软件工程"]];

    //注意加@
    [db executeUpdate:@"insert into person(name,age,money,classId) values(?,?,?,?);",@"cuiyw",@24,@200.3,@1001];
    [db executeUpdateWithFormat:@"insert into Person(name,age,money,classId) values(%@,%d,%f,%d)",@"cyw",23,210.9,1001];
}

-(void)selectData:(FMDatabase*)db
{
//    查询数据
    NSString *strsql=@"select id,name,age,money from Person";
//   FMResultSet返回结果集
    FMResultSet *set=[db executeQuery:strsql];
    while ([set next]) {
        int pid=[set intForColumn:@"id"];
        NSString *name=[set stringForColumnIndex:1];
        int age=[set intForColumn:@"age"];
        float money=[set doubleForColumnIndex:3];
        NSLog(@"%d %@   %d   %f",pid,name,age,money);
    }
    
    NSString *strsql1=@"select CId,CName from P_Class";
    //   FMResultSet返回结果集
    FMResultSet *set1=[db executeQuery:strsql1];
    while ([set1 next]) {
        NSString *name=[set1 stringForColumnIndex:1];
        int age=[set1 intForColumn:@"CId"];
//        float money=[set doubleForColumnIndex:2];
        NSLog(@"%@   %d   ",name,age);
    }
}
-(void)queueSelect:(FMDatabaseQueue*)queue
{
    //打开数据库
    [queue inDatabase:^(FMDatabase *db) {
        [self selectData:db];
    }];
}
//事务的两种写法
-(void)queueTransaction:(FMDatabaseQueue*)queue
{
    [queue inDatabase:^(FMDatabase *db) {
        [self selectData:db];
        [db beginTransaction];
        [db executeUpdate:@"update Person set money=money+20.0 where id=4"];
        [db executeUpdate:@"update Person set money=money-20.0 where id=3"];
        [db commit];
        [self selectData:db];
    }];
}

-(void)queueIntranscation:(FMDatabaseQueue*)queue
{
    [queue inTransaction:^(FMDatabase *db, BOOL *rollback) {
        [self selectData:db];
        [db executeUpdate:@"update Person set money=money+20.0 where id=4"];
        [db executeUpdate:@"update Person set money=money-20.0 where id=3"];
        [self selectData:db];
    }];
}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end