Guys anyone know postman api ?
Can any one help me how to add foreign key constraint using manytoone annotation?
Can anyone help me in batch?
Batch insert or update?
For ex: date or/and price range
For ex: date or/and price range
@Backhere bhai
For ex: date or/and price range
Use request body annotation, then use getter method of the pojo to get it’s value
after filter??
yes..
For ex: date or/and price range
U can javax validation on your pojo class flied.
& add @Valid on controller requestbody
It will open an interactive window
Add a commit message
Then hit esc so it will be back to same screen
Then :wq
It will save and exit vim
Or else
:q now
Do it from git gui
If just want to go back
:q
It’s a commit message
Basically you are in vim editor
:q
You do this , again you will be back in cli
Java Database Connectivity which is a specification for developing database applications with Java programming language.
The JDBC had several drawbacks
For example:
1. Boilerplate code (tedious code to work with data access Layer)
2. SQL exception-> Checked Exception so mandatorily needs to be handled.
3. Non portability because SQL codes are within the Java program; we can’t supply the SQL queries from outside the java program and also the SQL queries are database-specific.
4. Dialect issue in case of change of database
5. JDBC API can’t transfer the java objects directly
6. If the table structure is modified after the construction of Jdbc code then we must modify the sql queries again which is time consuming and burden for the java developer.
7. Manual resource clean up
8. Transactions must be handled manually
In order to overcome these problems spring JDBC was released.
It is an abstraction layer on top of jdbc technology.
Spring JDBC provides several methods to write the queries directly, so it saves a lot of work and time.
Spring JDBC however internally uses JDBC api only.
ORM:- (Object Relational Mapping) (To save the state of Java Objects into data base)
* It is a technique for converting/mapping data between java Objects and relational database
* Responsible for mapping the Domain Objects to Relational Model and vice versa
Why ORM?
Technical Differences between java Object and Relational Object
1. Granularity issue
2. Inheritance issue
3. Data Comparison issue
4. Data traversal difference
To overcome these technical problems, ORM was introduced.
They are several ORM tools available.
1. Hibernate
2. EclipseLink
3. OpenJPA
4. TopLink
5. Ibatis(MyBatis)
Which are all the implementations/JPA Providers/JPA vendors.
JPA (Java Persistence API) is a standard/specification/guidelines which are implemented/followed by all those ORM tools.
For easy understanding,
JPA is like an interface provided by the JCP( Java Community Process or Sun Microsystems (Oracle)) and ORM tools are the implementation classes
JPA facilities easy portability and migration.
With JPA, we can easily migrate from one JPA implementation to another JPA implementation.(Portability) (Loose Coupling)
Among all those JPA vendors, Hibernate (org.hibernate) is widely used because
1. It’s an Open source, publicly available without any cost and lightweight
2. Takes care of Auto Table Creation, Auto Primary Key generation
3. Provides Caching (Dual Layer caching) (first level and second level caching)
4. Supports Associations(mapping), inheritance, Joins
5. Provides Eager and lazy loading
6. Pagination support
7. Exception Handling is not mandatory.
8. Scalability
9. HQL (HIbernate Query Language) -> Database Independent Language
10. Transaction support
11. NativeSQL (we can write our SQL directly)
12. Locking -> Pessimistic and Optimistic Locking
13. Connection pooling mechanism for improving connection reusability
14. *Criteria API* which auto-generates *tuned Queries*
ORM tools however use the JDBC API internally
Der aaye durust aaye
Use @joincolumn
For ex: date or/and price range
By this I mean
In my request body user may or may not send some inputs like he need data before some date and price should be less then 1000 rs
This should not be delt with hibernate /jpa
And it is also possible that user will not these fields in request body itself
So my response should be based on his filter criteria
Batch insert or update?
Read write and process
Batch read?