+(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];  
        }