+(NSString*)databaseFilePath   
 
[objc] view plaincopy 
 
        {   
           
        NSArray*filePath=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);   
        NSString*documentPath=[filePathobjectAtIndex:0];   
        NSLog(@"%@",filePath);   
        NSString*dbFilePath=[documentPathstringByAppendingPathComponent:@"db.sqlite"];   
        returndbFilePath;   
           
        }   
    3、创建数据库的操作   
       
    +(void)creatDatabase   
        {   
        db=[[FMDatabasedatabaseWithPath:[selfdatabaseFilePath]]retain];   
        }   
    4、创建表   
       
    +(void)creatTable   
        {   
        //先判断数据库是否存在，如果不存在，创建数据库   
        if(!db){   
        [selfcreatDatabase];   
        }   
        //判断数据库是否已经打开，如果没有打开，提示失败   
        if(![dbopen]){   
        NSLog(@"数据库打开失败");   
        return;   
        }   
           
        //为数据库设置缓存，提高查询效率   
        [dbsetShouldCacheStatements:YES];   
           
        //判断数据库中是否已经存在这个表，如果不存在则创建该表   
        if(![dbtableExists:@"people"])   
        {   
        [dbexecuteUpdate:@"CREATETABLES people(people_id INTEGER PRIMARY KEY AUTOINCREAMENT, nameTEXT, age INTEGER) "];   
           
           
        NSLog(@"创建完成");   
        }   
           
        }   
    5、增加表数据   
       
    +(void)insertPeople:(People*)aPeople   
        {   
        if(!db){   
        [selfcreatDatabase];   
        }   
           
        if(![dbopen]){   
        NSLog(@"数据库打开失败");   
        return;   
        }   
           
        [dbsetShouldCacheStatements:YES];   
           
        if(![dbtableExists:@"people"])   
        {   
        [selfcreatTable];   
        }   
        //以上操作与创建表是做的判断逻辑相同   
        //现在表中查询有没有相同的元素，如果有，做修改操作   
        FMResultSet*rs=[dbexecuteQuery:@"select* from people where people_id = ?",[NSStringstringWithFormat:@"%d",aPeople.peopleID]];   
        if([rsnext])   
        {   
        NSLog(@"dddddslsdkien");   
        [dbexecuteUpdate:@"updatepeople set name = ?, age = ? where people_id =1",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]];   
        }   
        //向数据库中插入一条数据   
        else{   
        [dbexecuteUpdate:@"INSERTINTO people (name, age) VALUES(?,?)",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]];   
        }   
           
        }   
    6、删除数据   
       
    +(void)deletePeopleByID:(int)ID   
        {   
        if(!db){   
        [selfcreatDatabase];   
        }   
           
        if(![dbopen]){   
        NSLog(@"数据库打开失败");   
        return;   
        }   
           
        [dbsetShouldCacheStatements:YES];   
           
        //判断表中是否有指定的数据， 如果没有则无删除的必要，直接return   
        if(![dbtableExists:@"people"])   
        {   
        return;   
        }   
        //删除操作   
        [dbexecuteUpdate:@"deletefrom people where people_id = ?", [NSStringstringWithFormat:@"%d",ID]];   
           
        [dbclose];   
        }   
    7、修改操作与增加操作的步骤一致   
       
    +(NSArray*)getAllPeople   
        {   
           
        if(!db){   
        [selfcreatDatabase];   
        }   
           
        if(![dbopen]){   
        NSLog(@"数据库打开失败");   
        returnnil;   
        }   
           
        [dbsetShouldCacheStatements:YES];   
           
        if(![dbtableExists:@"people"])   
        {   
        returnnil;   
        }   
           
        //定义一个可变数组，用来存放查询的结果，返回给调用者   
        NSMutableArray*peopleArray=[[NSMutableArrayalloc]initWithArray:0];   
        //定义一个结果集，存放查询的数据   
        FMResultSet*rs=[dbexecuteQuery:@"select* from people"];   
        //判断结果集中是否有数据，如果有则取出数据   
        while([rsnext]){   
        People*aPeople=[[Peoplealloc]init];   
           
        aPeople.peopleID=[rsintForColumn:@"people_id"];   
        aPeople.name=[rsstringForColumn:@"name"];   
        aPeople.age=[rsintForColumn:@"age"];   
        //将查询到的数据放入数组中。   
        [peopleArrayaddObject:aPeople];   
        }   
        return[peopleArrayautorelease];   
        }   
    8、查询   
       
    +(NSArray*)getAllPeople   
        {   
           
        if(!db){   
        [selfcreatDatabase];   
        }   
           
        if(![dbopen]){   
        NSLog(@"数据库打开失败");   
        returnnil;   
        }   
           
        [dbsetShouldCacheStatements:YES];   
           
        if(![dbtableExists:@"people"])   
        {   
        returnnil;   
        }   
           
        //定义一个可变数组，用来存放查询的结果，返回给调用者   
        NSMutableArray*peopleArray=[[NSMutableArrayalloc]initWithArray:0];   
        //定义一个结果集，存放查询的数据   
        FMResultSet*rs=[dbexecuteQuery:@"select* from people"];   
        //判断结果集中是否有数据，如果有则取出数据   
        while([rsnext]){   
        People*aPeople=[[Peoplealloc]init];   
           
        aPeople.peopleID=[rsintForColumn:@"people_id"];   
        aPeople.name=[rsstringForColumn:@"name"];   
        aPeople.age=[rsintForColumn:@"age"];   
        //将查询到的数据放入数组中。   
        [peopleArrayaddObject:aPeople];   
        }   
        return[peopleArrayautorelease];   
        }