Deleting multiple records in IndexedDB based on index

Question

I am using IndexedDB and I have two object stores: equip (represents different equipment, primary key tagNo) and equipParts (represents the parts of a piece of equipment and has an index which is based on the tag number/serial number, primary key seqNo, with a field tagNo which represents the equipment that part is part of).

If I delete a record in equip, I want to delete all records in equipParts bearing the tagNo of equip (just like "where equipParts.tagNo = equip.tagNo").

Excerpt from my code:

var tx = db.transaction(["equip", "equipParts"],"readwrite");
var estore = tx.objectStore("equip");
var pstore = tx.objectStore("equipParts");
var tagIndex = pstore.index("by_tagNo");
var pdestroy = tagIndex.openCursor(IDBKeyRange.only(tagno)); //opens all records bearing the selected tag number
pdestroy.onsuccess = function() {
    var cursor = pdestroy.result;
    if (cursor) {
        if (cursor.value.tagNo == tagno) {
            pstore.delete(cursor.value.seqNo); //I guess I'm wrong here
        }
        cursor.continue;
    }
}
pdestroy.onerror = function() {
    alert("Deletion attempt NG");
}
var ereq = estore.delete(tagno);
ereq.onsuccess = function(e) {
    alert("Form deletion OK");
    window.location = "index.html";
}
ereq.onerror = function(e) {
    alert("Form deletion NG");
    window.location = "index.html";
}
db.close();

The problem is that only the record in equip is deleted; the records in equipParts stay there. Is there a way to delete multiple records in an IndexedDB object store based on a non-unique index (which can be the primary key of the parent object store)?

Answer 1

You have to get primary keys to delete the records.

var pdestroy = tagIndex.openKeyCursor(IDBKeyRange.only(tagno)); 
pdestroy.onsuccess = function() {
  var cursor = pdestroy.result;
  if (cursor) {
      pstore.delete(cursor.primaryKey);
      cursor.continue();
  }
}

Alternatively, but not efficient

var pdestroy = tagIndex.openCursor(IDBKeyRange.only(tagno)); 
pdestroy.onsuccess = function() {
  var cursor = pdestroy.result;
  if (cursor) {
      cursor.delete();
      cursor.continue();
  }
}

Answer 2

I found out an easiest approach with this

index.iterateCursor(IDBKeyRange, (cursor) => {
  if(cursor) {
    cursor.delete();
    cursor.continue();
  }
});

that way if you have it under an async function you can just use the

await index.iterateCursor...

and wait for the promise on the other side

Answer 3

I deleted multiple records belonging to an index by this way using idb :

var tx = idb.transaction("MyObjectStore", 'readwrite');
var index = tx.store.index('my_relid_idx');
var pdestroy = index.openCursor(RelID);
pdestroy.then(async cursor => {
    while (cursor) {
        cursor.delete();
        cursor = await cursor.continue();
    }
})