Question

我使用PostgreSQL 9.0

我想在树大小下显示单位的名称

这是表 unit

中数据库中的示例od数据

id_unit | id_parent | Name
 UN_1 |   NULL       | test1
 UN_2 |   NULL       | test2
 UN_3 |   UN_1       | test3
 UN_4 |   UN_1       | test4
 UN_5 |   UN_4       | test5
 UN_6 |   UN_7       | test6
 UN_7 |   UN_2       | test7
 UN_8 |   UN_4       | test8
 UN_9 |   UN_7       | test9

我希望以这种格式获取数据

  UN_1
          UN_3
          UN_4  UN_5
                UN_8
 UN_2  
           UN_7  UN_6
                 UN_9

我使用java方法来完成这项工作

 private List getChildrenUnitList(HttpServletRequest request,
        List uniteList, String lang, String employee) throws Exception {
        for (int i = 0; i < uniteList.size(); i++) {
            UnitEntity unitEntity = (UnitEntity) uniteList.get(i);
            UnitListEntity childreninitListEntity = getUniteList(request,
                    unitEntity.getId(), lang, employee);
            unitEntity.getChildrenlist_unit()
                      .addAll(getChildrenUnitList(request,
                    childreninitListEntity.getUnitList(), lang, employee));
        }

        return uniteList;
    }




       public UnitListEntity getUniteList(HttpServletRequest request, String id,
        String lang, String employee) throws Exception {
        UnitListEntity unitListEntity = new UnitListEntity();
        unitListEntity.setUnitList(unitDAO.findUnitListByIdEmployee(id, lang,
                employee));


        return unitListEntity;
    }

这是一个sql方法

 public List<UnitEntity> findUnitListByIdEmployee(String idParent, String lang, String idEmployee)
    throws Exception {
    String employees = "(select count(*) from employee where employee.id_unit = un.id_unit)";

SQLProperties properties = new SQLProperties();
properties.put("un.id_unit", UnitEntity.PROP_ID);
properties.put("un.name", UnitEntity.PROP_TEL_UNIT);
properties.put("un.order_unit", UnitEntity.PROP_ORDER_UNIT);
properties.put("un.id_parent", UnitEntity.PROP_ID_PARENT);

properties.put(employees, UnitEntity.PROP_EMPLOYEES, Hibernate.INTEGER);


String query = "SELECT ";


query += SQLUtils.getProperties(properties);


query += " FROM unit un";
query += " left outer join unit_lang un_lang  on un.id_unit = un_lang.id_unit";
query += (" WHERE statut = '1' and un_lang.lang_unit_lang ='" + lang + "' and un.active_unit='1'");



if ((idParent != null) && !"".equals(idParent)) {
    query += (" AND un.id_parent_unit = '" + idParent + "'");
} else {
    query += (" AND un.id_parent_unit IS NULL");
}

query += " ORDER BY order_unit";

SQLQuery sqlQuery = this.getSession().createSQLQuery(query);
sqlQuery = SQLUtils.addScalar(sqlQuery, properties);

sqlQuery.setResultTransformer(Transformers.aliasToBean(UnitEntity.class));

List<UnitEntity> list = sqlQuery.list();

return list;

}

postgres中的

我认为我应该使用递归查询，但我找不到解决方案

在单个查询中检索树

0 个答案: