how to query multiple objects

General
1

a user has contacts, a subset of all contacts stored.
instead of querying for updates on each individual user (incurring up to 100+ requests); i tried to batch the request into groups of 25.
my whereClause is of this form:
whereClause is objectId=1E538505-0A3F-EDE0-FF96-4C24F91DB800 OR objectId=ACCC0688-32BA-EDC8-FF88-3B5CB894CE00
this is my code:
BackendlessDataQuery dataQuery = new BackendlessDataQuery();
dataQuery.setWhereClause(whereClause);
Backendless.Persistence.of(BuContact.class).find(dataQuery, new AsyncCallback<BackendlessCollection<BuContact>>() {
and i get this error:
Error code is: 1017
batchError msg is: Invalid where clause
is it possible to retrieve multiple objects without using a relation?

2

the where clause is invalid because the type of the objectId column is STRING, which means the string values you reference in whereClause must be in single quotes:

objectId='1E538505-0A3F-EDE0-FF96-4C24F91DB800' OR objectId='ACCC0688-32BA-EDC8-FF88-3B5CB894CE00'

Here’s more compact form of the query:

objectId in ( 'objId1', 'objId2' )