从Indexeddb获取特定ID

syd619 发表于 Dev

syd619

在我的项目中，我使用浏览器的索引数据库，我想从数据库中检索具有特定ID的某些对象。根据MDN，您可以使用范围来获取所需的结果：

根据MDN：

// Only match "Donna"
var singleKeyRange = IDBKeyRange.only("Donna");

// Match anything past "Bill", including "Bill"
var lowerBoundKeyRange = IDBKeyRange.lowerBound("Bill");

// Match anything past "Bill", but don't include "Bill"
var lowerBoundOpenKeyRange = IDBKeyRange.lowerBound("Bill", true);

// Match anything up to, but not including, "Donna"
var upperBoundOpenKeyRange = IDBKeyRange.upperBound("Donna", true);

// Match anything between "Bill" and "Donna", but not including "Donna"
var boundKeyRange = IDBKeyRange.bound("Bill", "Donna", false, true);

// To use one of the key ranges, pass it in as the first argument of openCursor()/openKeyCursor()
index.openCursor(boundKeyRange).onsuccess = function(event) {
  var cursor = event.target.result;
  if (cursor) {
    // Do something with the matches.
    cursor.continue();
  }
};

但是，如果您希望通过单个请求获取不按顺序且不连续的特定ID数组（例如：[91,819,34,24,501]），该怎么办？

德哈特

通过使用光标一键获取多个对象是可能的。

键需要排序。

var keys = [91,819,34,24,501].sort(function(a, b) {
   return a - b;
});
var results = [];
var i = 0;
var cursorReq = store.openCursor();
cursorReq.onsuccess = function(e) {
   var c = e.target.result;
   if(!c) { return; /* done */ }
   while(c.key > keys[i]) {
      i++;
      if(i === keys.length) { return; /* done */ }
   }
   if(c.key === keys[i]) { // found
      results.push(cursor.value);
      c.continue();
   } else { c.continue(keys[i]); }
}