javascript - IndexedDB Fuzzy Search

Question

Ok, first of all, sorry for my English.

I'm working in a web project that show suggests when I type something in the inputbox, but I want to use IndexedDB to improve the query speed in Firefox.

With WebSQL I have this sentence:

db.transaction(function (tx) {
  var SQL = 'SELECT "column1", 
                    "column2" 
             FROM "table"
             WHERE "column1" LIKE ?
             ORDER BY "sortcolumn" DESC
             LIMIT 6';

  tx.executeSql(SQL, [searchTerm + '%'], function(tx, rs) {
    // Process code here
  });
});

I want to do same thing with IndexedDB and I have this code:

db.transaction(['table'], 'readonly')
  .objectStore('table')
  .index('sortcolumn')
  .openCursor(null, 'prev')
  .onsuccess = function (e) {
    e || (e = event);
    var cursor = e.target.result;
    if (cursor) {
        if (cursor.value.column1.substr(0, searchTerm.length) == searchTerm) {
            // Process code here
        } else {
            cursor.continue();
        }
    }
};

But there's too slow and my code is buggy.. I want to know is there a better way to do this.

Thank for reply.

Answer 1

I finally found the solution to this problem.

The solution consist to bound a key range between the search term and the search term with a 'z' letter at the final. Example:

db.transaction(['table'], 'readonly')
  .objectStore('table')
  .openCursor(
    IDBKeyRange.bound(searchTerm, searchTerm + 'uffff'), // The important part, thank Velmont to point out
    'prev')
  .onsuccess = function (e) {
    e || (e = event);
    var cursor = e.target.result;
    if (cursor) {
      // console.log(cursor.value.column1 + ' = ' + cursor.value.column2);
      cursor.continue();
    }
  };

Because I need to order the result, so I defined a array before the transaction, then we call it when we loaded all data, like this:

var result = [];
db.transaction(['table'], 'readonly')
  .objectStore('table')
  .openCursor(
    IDBKeyRange.bound(searchTerm, searchTerm + 'uffff'), // The important part, thank Velmont to point out
    'prev')
  .onsuccess = function (e) {
    e || (e = event);
    var cursor = e.target.result;
    if (cursor) {
      result.push([cursor.value.column1, cursor.value.sortcolumn]);
      cursor.continue();
    } else {
      if (result.length) {
        result.sort(function (a, b) {
          return a[1] - b[2];
        });
      }

      // Process code here
    }
  };