saqibmehmoodgit

Employee service                                             Course Service
@Autowired                                                    @Autowired
CourseService courseService;                                  @Transactional(propagation=Propagation.REQUIRES_NEW)
@Autowired                                                     public void saveCourse()
EmplyeeRepository empRepo;                                       {
@Transactional                                                        int a = 4;
public void saveEmplyee()                                                a =a/0; /// devide by zer exception
                                                                  }
{  
Empylye emp = new Empylye();

saqibmehmoodgit

      table   student
  bookid       authorid
  1             1
  1             2
  2             2
  
 select s.bookid  from  student  s 
    group by s.bookid
   having count(s.authorid)  =1
  Explaination ::::  As we know that "group by" is executed before "having" so first line number 8 will be executed 

saqibmehmoodgit

book table         |    author table  |    BOOK_AUTHORS
id   name          |     id  name     |     book_id    author_id
1    dubai visit   |     1   abc      |      1             1
2    pak visit     |     2   def      |      1             2  
                                      |      2             2
SELECT ba.book_Id FROM BOOK_AUTHORS ba
JOIN Book b ON ba.book_Id = b.id
JOIN BOOK_AUTHORS ba2 ON b.id = ba2.book_Id 
WHERE ba2.authors_Id = 2
GROUP BY ba.book_Id 

saqibmehmoodgit

Interface BatchPreparedStatementSetter
int	getBatchSize()
void	setValues(PreparedStatement ps, int i)

return this.jdbcTemplate.batchUpdate(
                    "update books set firstName = ? where id = ?",
                    new BatchPreparedStatementSetter() {

                        public void setValues(PreparedStatement ps, int i)
                                throws SQLException {

saqibmehmoodgit

 System.out.print("Write once, run everywhere!");	
		 System.out.println("");
		 System.out.println("Write");
		 System.out.println("once,");
		 System.out.println("run");
		 System.out.println("everywhere!");
		 System.out.println("*******************************");
		 System.out.println("* Write once, run everywhere! *");
		 System.out.println("*                             *");
		 System.out.print("*******************************");

saqibmehmoodgit

 System.out.print("Write once, run everywhere!");		
		 String[] array = {"Write","once,","run","everywhere!"};
		 for(int k = 0; k<=array.length-1; k++)
		 {
		 if(k==0)
		  {
		  System.out.println();		
		  for(int k3 = 0; k3<=array.length-1; k3++)
		   {
		    System.out.println(array[k3]);		 

saqibmehmoodgit

User                                       post                                                       userfriend
uid(pk)                                 pid     userid(fk)  title                            frid(pk)    userid(fk)         friendid(fk)
1                                        1        1          p1                                  1            1                   2
2                                        2        1          p2                                  2            1                   3
3                                        3        2          p3                                  3            2                   3
4                                        4        3          p4                                  4            3                   4
5                                        5        4          p5                                  5            4                   5

                 eexpected out put         title
                                            p1

saqibmehmoodgit

version 1                       version 2                        version 3 
@Entity                        public class UserPost           public class UserInstitute 
public class User               {                               {
{                                String name;                   String name;
 String name;                    List<Post> post ;              List<Insitiute> insitute;  
 List<Post> post ;              }                                }  
 List<Insitiute> insitute;
}
"select from User u fetch join u.post where id = 1"
it will result in inner join query so correct but 

saqibmehmoodgit

User(table)                                    Post(table)                            Comments(table)
userid name                                    postid title                          commntsid   commnets   userid  postid
  
@Entity                                       @Entity                                    @Entity
@Table(name = "user")                         @Table(name = "post")                      @Table(name = "comments")
public class User                             public class Post                          public class Comments
{                                              {                                         {
  @OneToMany(mappedBy = "user")                                                                               
 List<Post> post=new ArrayList<>();          @ManyToOne(fetch = FetchType.LAZY)              @ManyToOne(fetch = FetchType.LAZY)
                                              @JoinColumn(name = "uid")                      @JoinColumn(name = "uid")

saqibmehmoodgit

user                        friends 
userid   name                 uid    friendid 
1        abc                   1       2  
2        def                   1       3  
3        xyz                   2       3
4        ghf                   3       4  

where as  uid and friendid in friends table are composite  primary key and they are  forign key from userid of user tabale .
question 1) when i have to insert into friends table than i will insert like "insert into friends(udi , friendid) values(1,2)" . 
am i correct?