Start filtering the object store by creating a WhereClause instance.

Syntax

table.where(keyPathArray);
table.where({keyPath1: value1, keyPath2: value2, ...});

Parameters

Description

If a string, or array of strings was provided (indexes or primary keys), this method returns a WhereClause based on given index(es) or primary key(s). The returned WhereClause can be used to build a query on how to extract objects from the database using any of the methods in WhereClause. An array of strings represents compound indexes.

If a plain object containing criteria was provided, this method returns a Collection filtered using given criteria. If providing a single criteria, the keyPath must match with an index. If providing multiple criteria, it is recommended to have a compound index containing all of the keyPath (in arbitrary order), but it is not required. If no compound index, at least one of the keyPaths must match a simple index. If Dexie.debug=true and not having compound index of all provided keyPaths, a console.warn() will give a hint on how to index this query properly.

Return Value

WhereClause if string was provided

Collection if object was provided.

Samples

Find friends named david, ignoring case

const friends = await db.friends.where("name").equalsIgnoreCase("david").toArray();
for (const friend of friends) {
  console.log("Found: " + friend.name + ". Phone: " + friend.phoneNumber);
}

Find friends named David with age between 23 and 43 (two criteria)

const davids = await db.friends.where(["name", "age"])
  .between(["David", 23], ["David", 43], true, true)
  .toArray();
for (const david of davids) {
  console.log(`Found a David with age ${david.age}`);
}

NOTE: This example uses compound index ‘[name+age]’ to squeeze the most performance out of IndexedDB in finding records with multiple criteria. Not all types of criteria can be filtered this way, but combinations of a range in the last part and equals on the first parts works.

Find a friend named David with age 43

const david43 = await db.friends.where({name: "David", age: 43}).first();

The above statement is equivalent to:

const david43 = await db.friends.get({name: "David", age: 43});

See Also

WhereClause

Collection

API-Reference#query-items

Table.get()