Question

我想在时间表之间进行联接：

@Data
@AllArgsConstructor
@NoArgsConstructor
@Document(collection = TIMESHEET_COLLECTION)
public class Timesheet {

    @Id
    private ObjectId id;
    private ObjectId employeeId;
    private LocalDate date;
    private String occupationTitle;
    private BigDecimal salary;
    private List<TimesheetEntry> entries;
}

和员工（作为嵌入式文档）：

@Data
@AllArgsConstructor
@NoArgsConstructor
@Document(collection = Employee.EMPLOYEE_COL)
public class Employee {

    @Id
    private ObjectId id;
    private String registry;
    private String cpf;
    private String firstName;
    private String lastName;
    private String nickname;
    private String phone;
    private LocalDate dateOfBirth;
    private LocalDate admissionDate;
    private EmployeeOccupation occupation;
    private EmployeePaymentPreferences paymentPreferences;
    private Map<String, String> equipmentPreferences;
    private Boolean active;
}

所以我有这个 aggregation 查询，具有 match ， lookup ， unwind 和 projection < / strong>操作。

Aggregation aggregation = Aggregation.newAggregation(matchTimesheetFilter(timesheetFilter), lookupEmployee(), unwindEmployee(), projectEmployee());

有查找和展开实现。我要放松的原因是员工应该是单个对象，而不是数组。

private LookupOperation lookupEmployee(){ return LookupOperation.newLookup() .from("employee") .localField("employeeId") .foreignField("_id") .as("employee"); } private UnwindOperation unwindEmployee(){ return Aggregation.unwind("employee"); }

它成功返回带有嵌入式员工文档的时间表文档。关键是：我不想要所有数据。我只想要几个字段。

因此，我尝试使用投影操作从员工中排除不需要的字段：

private ProjectionOperation projectEmployee() { return Aggregation.project().andExclude("employee.nickname", "employee.firstName", "employee.fullName"); }

它没有用。我的嵌入式员工仍将返回所有字段。但是，如果执行以下操作，则可以成功地从时间表中排除字段：

private ProjectionOperation projectEmployee() { return Aggregation.project().andExclude("startDate", "endDate"); }

如何从通过查找操作嵌入的文档中投影自定义字段？

Answer 1

我认为您需要排除"employee.nickname", "employee.firstName", "employee.fullName"而不是"nickname", "firstName", "fullName"

尝试一下：

private ProjectionOperation projectEmployee() {
    return Aggregation.project().andExclude("employee.nickname", "employee.firstName", "employee.fullName");
}

Answer 2

我是这样做的（不确定它是否正确，但是否可行）：

private LookupOperation lookupEmployee(){
    return LookupOperation.newLookup()
            .from("employee")
            .localField("employeeId")
            .foreignField("_id")
            .as("employeeLookup");
}

no unwind used

Aggregation.project().and("employeeLookup.firstName").为("employee.firstName")

查找操作后投影嵌入式文档字段

2 个答案: