Hibernate共提供4种多表关联数据查询方式
OID数据查询+OGN数据查询方式
HQL数据查询方式
QBC数据查询方式
本地SQL查询方式(hibernate很少用)
1、OID数据查询+OGN数据查询方式
1 public class TestOID_OGN {
2
3 /**
4 * 什么时候时候什么时候发送
5 */
6 @Test
7 public void findUser() {
8 SessionFactory sf = H3Util.getSessionFactory();
9 Session session = sf.openSession();
10 Transaction ts = session.beginTransaction();
11 //小李子
12 User user = (User) session.get(User.class, "ff80808157c82de80157c82deb3c0001");
13 System.out.println("=========");
14
15 System.out.println(user);
16 ts.commit();
17 session.close();
18 }
19 }
2、HQL数据查询方式
/**
* HQL 数据查询
*/
public class TestHQL {
@Test
public void findUser() {
SessionFactory sf = H3Util.getSessionFactory();
Session session = sf.openSession();
Transaction ts = session.beginTransaction();
String hql = "from User";
Query query = session.createQuery(hql);
@SuppressWarnings("unchecked")
List<User> users = query.list();
for (User user : users) {
System.out.println("=="+user);
}
ts.commit();
session.close();
}
@Test
public void findUser1() {
SessionFactory sf = H3Util.getSessionFactory();
Session session = sf.openSession();
Transaction ts = session.beginTransaction();
//项目部中的所有 员工详细信息
String hql = "from Dept where deptname = ‘人事部‘";
Query query = session.createQuery(hql);
Dept dept = (Dept) query.uniqueResult();
//OGN
Set<User> list = dept.getUsers();
for (User user : list) {
System.out.println(user);
}
ts.commit();
session.close();
}
@Test
public void findUser2() {
SessionFactory sf = H3Util.getSessionFactory();
Session session = sf.openSession();
Transaction ts = session.beginTransaction();
//项目部中的所有 员工详细信息
//PO
//Dept dept = (Dept) session.get(Dept.class,"ff80808157c831050157c83106c40001");
//DO
Dept dept = new Dept();
dept.setDeptId("ff80808157c831050157c83106c40001");
//以对象作为条件查询：根据对象id
//只要保证该对象具备：OID PO DO
String hql = "from User where dept = ? ";
Query query = session.createQuery(hql);
query.setEntity(0, dept);
//什么类型都可以只使用
//query.setParameter(0, dept);
@SuppressWarnings("unchecked")
List<User> list = (List<User>) query.list();
System.out.println("=================");
for (User user : list) {
System.out.println("=="+user);
}
ts.commit();
session.close();
}
}
3、QBC数据查询方式
1 public class TestQBC {
2
3 @Test
4 public void findUser() {
5 SessionFactory sf = H3Util.getSessionFactory();
6 Session session = sf.openSession();
7 Transaction ts = session.beginTransaction();
8
9 Criteria criteria = session.createCriteria(User.class);
10 criteria.add(Restrictions.eq("username", "小小"));
11
12 User user = (User) criteria.uniqueResult();
13 //session.clear();
14 System.out.println("=========");
15 System.out.println(user.getDept());
16
17 ts.commit();
18 session.close();
19 }
20
21 @Test
22 public void findUser1() {
23 SessionFactory sf = H3Util.getSessionFactory();
24 Session session = sf.openSession();
25 Transaction ts = session.beginTransaction();
26
27 Dept dept = new Dept();
28 dept.setDeptId("ff80808157c831050157c83106c40001");
29
30 Criteria criteria = session.createCriteria(User.class);
31 criteria.add(Restrictions.eq("dept", dept));
32
33 @SuppressWarnings("unchecked")
34 List<User> list = criteria.list();
35 System.out.println("=========分割线===========");
36 for (User user : list) {
37 System.out.println(user);
38 }
39
40 ts.commit();
41 session.close();
42 }
43
44 @Test
45 public void findUser2() {
46 SessionFactory sf = H3Util.getSessionFactory();
47 Session session = sf.openSession();
48 Transaction ts = session.beginTransaction();
49
50 Dept dept = (Dept) session.get(Dept.class, "ff80808157c831050157c83106c40001");
51
52 //from User dept.deptId = ‘4028408157c14c210157c14c25370000‘
53 Criteria criteria = session.createCriteria(User.class);
54 //使用OGN：OID
55 criteria.add(Restrictions.eq("dept.deptId", dept.getDeptId()));
56
57
58 System.out.println("==========分割线============");
59 @SuppressWarnings("unchecked")
60 List<User> list = criteria.list();
61 for (User user : list) {
62 System.out.println(user);
63 }
64
65 ts.commit();
66 session.close();
67 }
68
69
70 @Test
71 public void findUser3() {
72 SessionFactory sf = H3Util.getSessionFactory();
73 Session session = sf.openSession();
74 Transaction ts = session.beginTransaction();
75
76 Dept dept = (Dept) session.get(Dept.class, "ff80808157c831050157c83106c40001");
77
78 //from User dept.deptName = ‘项目部‘
79 Criteria criteria = session.createCriteria(User.class);
80 //QBC:ONG方式中如果使用的的OID可以查询，但是如果使用的是除OID之外的其它属性
81 //就会报异常,解决方案：createAlias("dept")
82 //为dept起别名
83 criteria.createAlias("dept", "dept");
84 criteria.add(Restrictions.eq("dept.deptName", dept.getDeptName()));
85
86 @SuppressWarnings("unchecked")
87 List<User> list = criteria.list();
88 System.out.println("==========分割线===========");
89 for (User user : list) {
90 System.out.println(user);
91 }
92
93 ts.commit();
94 session.close();
95 }
96 }
4、HQL数据查询方式（测试内连接，外连接查询）
1 /**
2 * @author nunu
3 * 测试内连接，外连接查询
4 */
5 public class TestHQL2 {
6
7
8 /**
9 * 内连接：
10 * 有关联数据：
11 * 数据总量：从表被关联的数据总量
12 * 数据模型：主表数据(延迟从) + 从表数据(含主)
13 *
14 */
15 @Test
16 public void findUser() {
17 SessionFactory sf = H3Util.getSessionFactory();
18 Session session = sf.openSession();
19 Transaction ts = session.beginTransaction();
20
21 //部门：主表
22 //员工：从表
23 //sql：select d.*,u.* from t_dept d inner join t_user u on d.dept_id = u.dept_id;
24 String hql = "from Dept d inner join d.users";
25 Query query = session.createQuery(hql);
26
27 @SuppressWarnings("unchecked")
28 List<Object[]> list = query.list();
29 System.out.println(list.size());
30
31 System.out.println("==========分割线===========");
32 for (int i = 0; i < list.size(); i++) {
33 Object[] objs = list.get(i);
34 //主表数据
35 Dept dept = (Dept) objs[0];
36 User user = (User) objs[1];
37 System.out.println(user);
38 System.out.println(dept);
39 /*
40 //主表关联数据
41 Set<User> userSet = dept.getUsers();
42 for (User user : userSet) {
43 //如果延迟加载:回发送新语句查询
44 System.out.println(user);
45 }
46 */
47 System.out.println("==");
48 /*
49 //从表数据
50 User user = (User) objs[1];
51
52 //从表关联数据
53 Dept dept = user.getDept();
54
55 System.out.println(dept);
56 */
57 }
58
59 ts.commit();
60 session.close();
61 }
62
63
64 /**
65 * 迫切内连接(数据重复DISTINCT)
66 * 数据总量：从表被关联的数据总量
67 * 数据模型：主表数据 (含从)
68 */
69 @Test
70 public void findUser1() {
71 SessionFactory sf = H3Util.getSessionFactory();
72 Session session = sf.openSession();
73 Transaction ts = session.beginTransaction();
74
75 //部门：主表
76 //员工：从表
77 //sql：select d.*,u.* from t_dept d inner join t_user u on d.dept_id = u.dept_id;
78 String hql = "from Dept d inner join fetch d.users";
79 Query query = session.createQuery(hql);
80 @SuppressWarnings("unchecked")
81 List<Dept> list = query.list();
82 System.out.println(list.size());
83 System.out.println("===============分隔符=================");
84 session.clear();
85 for (Dept dept : list) {
86 Set<User> users = dept.getUsers();
87 for (User user : users) {
88 System.out.println(user);
89 }
90 System.out.println("---------");
91 }
92
93 ts.commit();
94 session.close();
95 }
96
97
98 /**
99 * 隐式内连接
100 * 数据总量：主表数据总量
101 * 数据模型：主表数据(延迟从)
102 */
103 @Test
104 public void findUser2() {
105 SessionFactory sf = H3Util.getSessionFactory();
106 Session session = sf.openSession();
107 Transaction ts = session.beginTransaction();
108
109 //部门：主表
110 //员工：从表
111 //sql：select d.*,u.* from t_dept d inner join t_user u on d.dept_id = u.dept_id;
112 String hql = "from Dept"; //默认就会用户关联了
113 Query query = session.createQuery(hql);
114 @SuppressWarnings("unchecked")
115 List<Dept> list = query.list();
116 System.out.println(list.size());
117 //session.clear();
118 System.out.println("===============分隔符=================");
119 for (Dept dept : list) {
120 Set<User> users = dept.getUsers();
121 for (User user : users) {
122 System.out.println(user);
123 }
124 System.out.println("-----------------");
125 }
126
127 ts.commit();
128 session.close();
129 }
130
131
132 /**
133 左外连接: 以左侧表为准
134 数据总量：从表被关联数据总量+主表未关联数据总量
135 数据模型：主表数据(延迟从) ，从表数据 (含主)
136 (主表不存在关联数据的从表数据为0)
137 */
138 @Test
139 public void findUser3() {
140 SessionFactory sf = H3Util.getSessionFactory();
141 Session session = sf.openSession();
142 Transaction ts = session.beginTransaction();
143
144 //部门：主表
145 //员工：从表
146 //sql：select d.*,u.* from t_dept d inner join t_user u on d.dept_id = u.dept_id;
147 String hql = "from Dept d left outer join d.users";//默认就会用户关联了
148 Query query = session.createQuery(hql);
149
150 @SuppressWarnings("unchecked")
151 List<Object[]> list = query.list();
152 System.out.println(list.size());
153
154 System.out.println("============分隔符==============");
155 for (int i = 0; i < list.size(); i++) {
156 Object[] objs = list.get(i);
157 //主表数据
158 System.out.println("\t ==主表数据");
159 Dept dept = (Dept) objs[0];
160 System.out.println("\t "+dept);
161
162 System.out.println("\t ==主表关联数据");
163 //主表关联数据
164 Set<User> userSet = dept.getUsers();
165 for (User user : userSet) {
166 //如果延迟加载:回发送新语句查询
167 System.out.println("\t "+user);
168 }
169
170 System.out.println("\t ==从表数据");
171 //从表数据
172 User user = (User) objs[1];
173 System.out.println("\t "+user);
174
175 System.out.println("\t ==从表关联数据");
176 //从表关联数据
177 Dept dept1 = user.getDept();
178
179 System.out.println("\t "+dept1);
180 System.out.println("-------------");
181 }
182 ts.commit();
183 session.close();
184 }
185
186
187 /**
188 * 迫切左外连接(数据重复DISTINCT)
189 数据总量：从表被关联数据总量+主表未关联数据总量
190 数据模型：主表数据(含从)
191 (主表不存在关联数据的从表数据为0)
192 */
193 @Test
194 public void findUser4() {
195 SessionFactory sf = H3Util.getSessionFactory();
196 Session session = sf.openSession();
197 Transaction ts = session.beginTransaction();
198
199 //部门：主表
200 //员工：从表
201 //sql：select d.*,u.* from t_dept d inner join t_user u on d.dept_id = u.dept_id;
202 String hql = "from Dept d left outer join fetch d.users";//默认就会用户关联了
203 Query query = session.createQuery(hql);
204
205 @SuppressWarnings("unchecked")
206 List<Dept> list = query.list();
207 System.out.println("============分隔符==============");
208 for (Dept dept : list) {
209 System.out.println(dept);
210
211 Set<User> userSet = dept.getUsers();
212 for (User user : userSet) {
213 System.out.println(user);
214 }
215 System.out.println("-----------");
216 }
217 ts.commit();
218 session.close();
219 }
220
221
222
223 /**
224 * 右外连接:
225 数据总量：从表数据总量
226 数据模型：主表数据(延迟从) ，从表数据(含主)
227 (从表不存在关联数据的主表数据为null)
228 */
229 @Test
230 public void findUser5() {
231 SessionFactory sf = H3Util.getSessionFactory();
232 Session session = sf.openSession();
233 Transaction ts = session.beginTransaction();
234
235 //部门：主表
236 //员工：从表
237 //sql：select d.*,u.* from t_dept d inner join t_user u on d.dept_id = u.dept_id;
238 String hql = "from Dept d right outer join d.users";//默认就会用户关联了
239 Query query = session.createQuery(hql);
240
241 @SuppressWarnings("unchecked")
242 List<Object[]> list = query.list();
243 System.out.println(list.size());
244 System.out.println("=============分隔符=================");
245 for (int i = 0; i < list.size(); i++) {
246 Object[] objs = list.get(i);
247 //主表数据
248 //Dept dept = (Dept) objs[0];
249 //System.out.println(dept.getDeptName());
250
251
252 //主表关联数据
253 /*Set<User> userSet = dept.getUsers();
254 for (User user : userSet) {
255 //如果延迟加载:回发送新语句查询
256 System.out.println(user.getUserId());
257 }*/
258
259 //从表数据
260 User user = (User) objs[1];
261 System.out.println(user);
262
263 //从表关联数据
264 // Dept dept = user.getDept();
265 // System.out.println(dept.getDeptName());
266 // System.out.println(user.getUsername());
267 System.out.println("-------------");
268 }
269 ts.commit();
270 session.close();
271 ts.commit();
272 session.close();
273 }
274
275
276 }
时间： 2024-12-25 00:35:51