利用object-c反射功能封装FMDB

最新推荐文章于 2025-08-23 16:56:09 发布

转载最新推荐文章于 2025-08-23 16:56:09 发布 · 725 阅读

文章标签：

#properties #sql #interface #class #encoding #insert

本文介绍了一种利用Objective-C的反射机制来简化FMDB操作SQLite数据库的方法，通过获取对象属性自动生成SQL插入语句，减少了冗余代码。

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http://hi.baidu.com/%CA%FD%D1%A7rubish/blog/item/fabea81efe7dae7cf724e4ea.html

在利用fmdb操作sqllite的时候，感觉存在很多冗余代码，所以偶发其想，想到了java的反射，java的很多orm框架都利用了反射这一高级语言的功能，我只能说很好很强大

coredata没见过源码，我感觉或多或少应该也是应用的反射功能

google了一些资料，决定封装一个保存功能，此处暂提供一个思路，具体还需要修改优化

代码如下：

-(void)saveEntity:(Entity *)entity{

    Class class = [entity class];

    unsigned int outCount;

    objc_property_t *properties = class_copyPropertyList(class,&outCount);

    NSString *sql = [NSString stringWithFormat:@" INSERT INTO %@ (",[entity tableName]];

    NSString *sqlValue = @" VALUES (";

    NSMutableArray *dic = [[NSMutableArray alloc] initWithCapacity:5];

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

        const char *pName = property_getName(properties[i]);

        NSString *propertyName = [NSString stringWithCString:pName encoding:NSUTF8StringEncoding];

        NSObject *value = [entity valueForKey:propertyName];

        if(value != nil){
            [dic addObject:value];
        }

        if(i == outCount - 1){
            sql = [sql stringByAppendingString:propertyName];
            sqlValue = [sqlValue stringByAppendingString:@"?"];
            //sqlValue = [sqlValue stringByAppendingFormat:@"%@",value];
        }else {
            sql = [sql stringByAppendingString:propertyName];
            sqlValue = [sqlValue stringByAppendingString:@"?"];
            //sqlValue = [sqlValue stringByAppendingFormat:@"%@",value];
            sql = [sql stringByAppendingString:@","];
            sqlValue = [sqlValue stringByAppendingString:@","];
        }

    }

    sql = [sql stringByAppendingString:@")"];
    sqlValue = [sqlValue stringByAppendingString:@")"];

    free(properties);

    NSLog(@"%@",[NSString stringWithFormat:@"%@%@",sql,sqlValue]);

    SqliteInterface *interface = [SqliteInterface sharedSqliteInterface];

    FMDatabase *db = [interface connectDB];

    [db beginTransaction];
    [db executeUpdate:[NSString stringWithFormat:@"%@%@",sql,sqlValue]withArgumentsInArray:dic];
    [db commit];

    [interface closeDB];


}