Update

Use Update<T>(), Set(...), and an explicit filter.

var affected = connection
    .UseDb4Net(Db4NetOptions.SqlServer)
    .Update<User>()
    .Set(u => u.Name, "Alice")
    .Where(u => u.Id, Op.Eq, 1)
    .Execute();

Set(...) accepts typed member selectors. Filters use the same Where(...), OrWhere(...), WhereGroup(...), and OrWhereGroup(...) APIs as select queries.

Entity Values and Keys

Use Update(entity) when you want mapped non-key values and key predicates read from an object.

var affected = db.Update(user)
    .Execute();

Use WhereKey(entity) with an explicit builder when only the key predicate should come from the object.

var affected = db.Update<User>()
    .Set(u => u.Name, "Alice")
    .WhereKey(user)
    .Execute();

Update(entity) and WhereKey(entity) require exactly one mapped key and a non-default key value. Use explicit Where(...) clauses for composite-key models.

All Rows

UPDATE requires a WHERE clause by default.

var affected = db.Update<User>()
    .Set(u => u.IsActive, false)
    .AllowAllRows()
    .Execute();

WARNING

Call AllowAllRows() only when intentionally updating every row.