I am working on a Spring-MVC application where I have a many-to-many relationship in which I have to query in 2 tables to get the values I require. I will explain in more detail.
This is what I am looking for :
SQL code :
CREATE TABLE public.groupaccount (
groupid NUMERIC NOT NULL,
groupname VARCHAR,
adminpassword VARCHAR,
groupaccountstatus BOOLEAN DEFAULT false NOT NULL,
adminusername VARCHAR,
CONSTRAINT groupid PRIMARY KEY (groupid)
);
CREATE TABLE public.groupmembers (
memberid INTEGER NOT NULL,
musername VARCHAR,
mpassword VARCHAR,
memberaccountstatus BOOLEAN DEFAULT false NOT NULL,
currentcanvasid NUMERIC DEFAULT 0 NOT NULL,
CONSTRAINT memberid PRIMARY KEY (memberid)
);
CREATE TABLE public.memberjunction (
memberid INTEGER NOT NULL,
groupid NUMERIC NOT NULL,
CONSTRAINT membergroupid PRIMARY KEY (memberid, groupid)
);
GorupMembersDAOImpl :
@Override
public List<Integer> returnMemberIdWithMatchingUsername(String memberUsername) {
session = this.sessionFactory.getCurrentSession();
org.hibernate.Query query = session.createQuery("From GroupMembers as " +
"n where n.memberUsername=:memberUsername");
query.setParameter("memberUsername",memberUsername);
List<GroupMembers> memberList = query.list();
List<Integer> memberIdList = new ArrayList<>();
for(GroupMembers members :memberList){
memberIdList.add(members.getMemberid());
}
return memberIdList;
}
Now as I have the memberIdList, I just want to check for each value in MemberJunction where memberIdList matches. Any help would be nice. Please note, I don't have any separate classes for memberjunction. Thanks a lot. :-)
For Ramesh :
GroupAccount model class :
@Entity
@Table(name="groupaccount")
public class GroupAccount {
@Id
@Column(name="groupid")
@GeneratedValue(strategy = GenerationType.SEQUENCE,generator = "groupaccount_seq_gen")
@SequenceGenerator(name = "groupaccount_seq_gen",sequenceName = "groupaccount_seq")
private Long groupId;
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name = "memberjunction", joinColumns = {@JoinColumn(name = "groupid")},
inverseJoinColumns = {@JoinColumn(name = "memberid")})
private Set<GroupMembers> groupMembersSet = new HashSet<>();
public void setGroupMembersSet(Set<GroupMembers> groupMembersSet){
this.groupMembersSet = groupMembersSet;
}
}
GroupMembers :
@Entity
@Table(name="groupmembers")
public class GroupMembers {
@Id
@Column(name="memberid")
@GeneratedValue(strategy = GenerationType.SEQUENCE,generator = "groupmembers_seq_gen")
@SequenceGenerator(name = "groupmembers_seq_gen",sequenceName = "groupmembers_seq")
private int memberid;
@ManyToMany(mappedBy = "groupMembersSet")
private Set<GroupAccount> groupAccounts = new HashSet<>();
public void setGroupAccounts(Set<GroupAccount> groupAccounts){
this.groupAccounts = groupAccounts;
}
public Set<GroupAccount> getGroupAccounts(){
return this.groupAccounts;
}
}
If you want group accounts that is linked with group member you can use following query .
@Override
public List<GroupAccount> returnMemberIdWithMatchingUsername(String memberUsername) {
session = this.sessionFactory.getCurrentSession();
org.hibernate.Query query = session.createQuery("Select ga From GroupAccount as " +
"ga INNER JOIN ga.groupMembersSet as gm where gm.memberUsername=:memberUsername");
query.setParameter("memberUsername",memberUsername);
List<GroupAccount> groupAccountList = query.list();
return groupAccountList;
}
if u want count u can try
@Override
public Integer returnMemberIdWithMatchingUsername(String memberUsername) {
session = this.sessionFactory.getCurrentSession();
org.hibernate.Query query = session.createQuery("Select count(ga) From GroupAccount as " +
"ga INNER JOIN ga.groupMembersSet as gm where gm.memberUsername=:memberUsername");
query.setParameter("memberUsername",memberUsername);
Integer count = (Integer) query.list().get(0);
return count;
}
Hope it helps . If u have any prob with these queries update me
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