objective-c - FMDB 使用字典查询

Question

我需要运行一个看起来像这样的查询

INSERT INTO Appointments (field1, field2, field3, ..., field30) VALUES (value1, value2, value3, ..., value30)

我将我的约会存储在一个字典中，我想遍历该字典以使键等于字段并且值等于值。

我正在尝试使用 executeUpdate:... withParameterDictionary:... 但如果我不知道字段名称，就无法弄清楚如何使它与多个字段一起使用.字段名称通过 JSON 发送，而不是手动输入 30 个字段，我只想循环遍历字典并以这种方式获取它们。

我试过了

NSMutableArray *keys = nil;
 NSMutableArray *values = nil;

        for (NSDictionary *dict in [json objectForKey:@"data"]) {
            keys = [NSMutableArray array];
            values = [NSMutableArray array];
            for (id key in dict) {
                [keys addObject:key];
                [values addObject:[NSString stringWithFormat:@":%@", key]];
            }
            NSString *keyString = [keys componentsJoinedByString:@","];
            NSString *valueString = [values componentsJoinedByString:@","];
            [[dataObj db] executeUpdate:@"DELETE FROM Appointments"];
            NSLog(@"INSERT INTO Appointments (%@) VALUES (%@)", keyString, valueString);
            [[dataObj db] executeUpdate:@"INSERT INTO Appointments (?) VALUES (?)", keyString, valueString];

        }

上面的代码打印了 NSLog 查询的外观，但没有向数据库中插入任何内容。我知道这一点，因为我在查询运行后打开模拟器数据库文件，但它仍然是空白的。

我怎样才能让上面的代码工作，或者我怎样才能让 executeQuery:... withParameterDictionary:... 处理多个名称。

Answer 1

我进行了几次快速测试，这对我有用:

NSDictionary* dict = [NSDictionary dictionaryWithObjectsAndKeys:@"AAAA44", @"a", @"BBBB44", @"b", @"CCCC44", @"c", nil];
NSMutableArray* cols = [[NSMutableArray alloc] init];
NSMutableArray* vals = [[NSMutableArray alloc] init];
for (id key in dict) {
    [cols addObject:key];
    [vals addObject:[dict objectForKey:key]];
}
NSMutableArray* newCols = [[NSMutableArray alloc] init];
NSMutableArray* newVals = [[NSMutableArray alloc] init];
for (int i = 0; i<[cols count]; i++) {
    [newCols addObject:[NSString stringWithFormat:@"'%@'", [cols objectAtIndex:i]]];
    [newVals addObject:[NSString stringWithFormat:@"'%@'", [vals objectAtIndex:i]]];
}
NSString* sql = [NSString stringWithFormat:@"insert into test (%@) values (%@)", [newCols componentsJoinedByString:@", "], [newVals componentsJoinedByString:@", "]];
NSLog(@"%@", sql);
BOOL updateSuccess = [db executeUpdate:sql];

诀窍是将 ' 添加到数组中的数据。