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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(); |
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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 |
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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 |
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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 { |
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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("*******************************"); |
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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]); |
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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 |
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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 |
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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") |
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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? |
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