indexeddb

问题 I want to execute this query select * from properties where propertyCode IN ("field1", "field2", "field3") How can I achieve this in IndexedDB I tried this thing getData : function (indexName, params, objectStoreName) { var defer = $q.defer(), db, transaction, index, cursorRequest, request, objectStore, resultSet, dataList = []; request = indexedDB.open('test'); request.onsuccess = function (event) { db = request.result; transaction = db.transaction(objectStoreName); objectStore = transaction

问题 I have a table where each object has a field that is an array of strings: for example, { people: ['John', 'Bob', 'Sue'] } . I need all objects in the table that have 'Sue' in the people array. Can Dexie do this? 回答1: Yes, using MultiEntry indexes you can do exactly that. const db = new Dexie("testdb"); db.version(2).stores({ groups: 'id, *people' }); async function addRow() { await db.groups.add({id: 1, people: ['John', 'Bob', 'Sue']}); } async function findSuesGroups() ( return await db

问题 In indexedDB, if the keys are arrays of integers such as [n,0] through [n,m] , for operations that involve getting all the records in which the first element of the array key is n or opening a cursor on the same set of records, is there any advantage to using an index on an additonal property that stores n over using a key range? Reasons to think an index may not be better include that the browser has to maintain the index for each change to the object store, an additional property has to be

问题 I'm building an offline HTML5 app (it will be delivered as a zipped up .crx file). It will be installed and used entirely offline. At no point will there be internet access. AFAIK, there is no way to include a pre-populated sqlite DB (and I know you cannot include an indexedDB), so all the data must be included outside a database, but accessible to the javascript code, and then on the first run, put into the database. What's the best way to do this? (Both from a development/maintenance

问题 For an object store with an array key of [a,b] where a is also an index, is there a more efficient way to delete all records for a specific value of a than opening a cursor on the index a and deleting each record as step through the cursor? Is there a way to define a key range for an index only, or just on a and leave b open to any value, such that can delete all records for that key range? In this particular case, a is a positive integer excluding zero and b is a positive integer including

问题 For an object store with an array key of [a,b] where a is also an index, is there a more efficient way to delete all records for a specific value of a than opening a cursor on the index a and deleting each record as step through the cursor? Is there a way to define a key range for an index only, or just on a and leave b open to any value, such that can delete all records for that key range? In this particular case, a is a positive integer excluding zero and b is a positive integer including

问题 Given a indexeddb database with one declared objectstore as: var objectStore = thisDb.createObjectStore("table", {keyPath: "id", autoIncrement: true}) When I add an new item with the add request: var resp = objectStore.add(row) How can I get the new id of this added item in the onsuccess function? resp.onsuccess = function(e) { /* code to get the id of the added item */} 回答1: You can find the inserted key in e.target.result. 来源： https://stackoverflow.com/questions/13492785/getting-the-id-of

问题 Given a indexeddb database with one declared objectstore as: var objectStore = thisDb.createObjectStore("table", {keyPath: "id", autoIncrement: true}) When I add an new item with the add request: var resp = objectStore.add(row) How can I get the new id of this added item in the onsuccess function? resp.onsuccess = function(e) { /* code to get the id of the added item */} 回答1: You can find the inserted key in e.target.result. 来源： https://stackoverflow.com/questions/13492785/getting-the-id-of

问题 Taking the following pseudo code localforageStore.setItem('foo', 'bar') .then(console.log('foo is persisted to disk')); localforageStore.getItem('foo') .then(v => console.info('foo is '+v)); // A, B or C? Is the console.info:- A. Guaranteed to display 'bar' B. Guaranteed to display 'undefined' C. Indeterminate i.e. even though the write to disc is async, will a synchronous read be resolved from a buffer internal to indexeddb and/or localforage? 回答1: I took a look at the localForage indexedDB

问题 How does IndexedDB handle multiple tabs each with asynchronous transactions in-flight? Do transactions lock all of the related object stores entirely? How can I guarantee that if one tab is working on a piece of data that another isn't doing the same thing? 回答1: The IndexedDB specifications determine that "If multiple READ_WRITE transactions are attempting to access the same object store (i.e. if they have overlapping scope), the transaction that was created first must be the transaction