特定领域数据库值必须更新

Question

我正在React Native中实现Realm。上下文是我在顶部声明了2个架构，即“ PortfolioData”，其架构类型为“ PriceAChangeSchema”。

现在，在更新屏幕上，我只需要更新PriceAChangeSchema中的3个值，即balance，lastPrice和totalVal。当我尝试仅将3个值推入领域写入功能时，它成功地覆盖了3个值，但是PriceAChange模式的其余值变为空，这是我不希望的。

P.S推送后，PortfolioData的值保持不变，但PriceAChange模式值变为空。 ？

class PriceAChangeSchema extends Realm.Object { }

PriceAChangeSchema.schema = {

    name: 'PriceAChange',
    properties: {
        icon: 'string?',
        cryptoName: 'string?',
        balance: 'string?',
        lastPrice: 'string?',
        change: 'string?',
        totalVal: 'string?',
    }
};

class PortfolioDataSchema extends Realm.Object { }

PortfolioDataSchema.schema = {

    name: 'PortfolioData',
    primaryKey: 'select',
    properties: {
        from: 'string?',
        select: 'string',
        apikey: 'string?',
        secretkey: 'string?',
        address: 'string?',
        logoLink: 'string?',
        priceandchange: 'PriceAChange[]'
    }
}

realm.write(() => {
            const ExchangeIns = realm.create('PortfolioData', {
                select: select, //primary key
                priceandchange: [], //want to change specifics
            }, true);

            ExchangeIns.priceandchange.push({
                balance: '0.004',
                lastPrice: '2.22',
                totalVal: '3.5',
            });
        });