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QueryProvider
Typed data queries in rules – create/where/and/orderBy/execute, getByState, getByProcess, subqueries.
REFERENZ DEVELOPER UPDATED: JUL 2026 APPLIES TO NUCLOS 4.2026.X
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What is the QueryProvider for?
The QueryProvider loads data from Nuclos and provides it as a business object or list in rules. Instead of SQL it uses a typed, abstract query language.
Logically deleted entries
Without NuclosLogicalDeleted, logically deleted entries are not considered. Only NuclosLogicalDeleted.eq(Boolean.TRUE) returns deleted entries.
create(type)
Creates a typed Query object for a business object.
public static <T extends BusinessObject> Query<T> create(Class<T> type);
execute(query)
Runs the query and returns a typed, never-null list (empty if no hit).
public static <T extends BusinessObject> List<T> execute(Query<T> query);
get(id)
Reads a specific entry by type and id; null if nothing is found.
getByState / getByProcess
Search entries by state or by assigned action (process). At least one state/action is required.
Conditions & combining
Fields offer matching comparison operators: eq, neq, isNull, notNull (all types) plus Gt, Gte, Lt, Lte (numeric). where()/and()/orderBy() return the query and can be chained. or() exists only at the SearchExpression level, allowing nested blocks.
boolean sortAscending = true;
Query<Auftrag> queryAuftrag = QueryProvider.create(Auftrag.class);
queryAuftrag.where(Auftrag.Auftragsnr.notNull())
.and(Auftrag.Bestellwert.Gt(BigDecimal.ZERO))
.orderBy(Auftrag.Auftragsnr, sortAscending);
Execute & iterate
List<Auftrag> results = QueryProvider.execute(queryAuftrag);
for (Auftrag a :results) {
BigDecimal bestellwert = a.getBestellwert();
}
Subqueries (exist)
With exist(subQuery, …) subqueries can be embedded via (foreign) keys; the subquery itself is not executed separately.
// Alle Kunden, fuer die Zahlungsbedingungen hinterlegt wurden
Query<Kunde> qryKunden = QueryProvider.create(Kunde.class);
qryKunden.where(Kunde.Zahlungsbedingung.notNull());
// Nun brauchen wir alle Bestellungen dieser Kunden
Query<Bestellung> queryBestellungen = QueryProvider.create(Bestellung.class);
queryBestellungen.where(Bestellung.Bestellnr.notNull())
.exist(qryKunden, Bestellung.KundeId)
.orderBy(Bestellung.Bestellnr, true);
List<Bestellung> results = QueryProvider.execute(queryBestellungen);
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