我正在学习indexeddb，在比较下面的两个函数时感到困惑。它们是相同的，除了我将代码#2的最后一个request变量名改为变量request2名称。这导致它们产生不同的结果。
代码#1

function updateEntry(){
    var tx = db.transaction('practiceStore', 'readwrite');
    var store = tx.objectStore('practiceStore');
    var request = store.get(3);
    request.onsuccess = event => {
        console.log(request.result)
        let entry = request.result;
        
        entry.title = 'mdn way'
        var request = store.put(entry)
        request.onsuccess = event => {
            console.log('putting')
        }
    }
    tx.oncomplete = event => {
        console.log('tx complete')
    }
}

输出：

errors

与
代码#2

function updateEntry(){
    var tx = db.transaction('practiceStore', 'readwrite');
    var store = tx.objectStore('practiceStore');
    var request = store.get(3);
    request.onsuccess = event => {
        console.log(request.result)
        let entry = request.result;
        
        entry.title = 'mdn way'
        var request2 = store.put(entry)
        request2.onsuccess = event => {
            console.log('putting')
        }
    }
    tx.oncomplete = event => {
        console.log('tx complete')
    }
}

输出

//does expected behavior

代码#1错误在console.log(request.result)行。我尝试使用chrome devtools调试器，发现调试器从来没有使它到var request = store.put(entry)，这使我更加困惑。
代码#1错误，因为请求未定义。我在概念上不明白重新定义request以后会改变什么。任何帮助都很感激，谢谢。