CRUD Operations
Learn how to perform CRUD operations using methods offered by the EntityManager.
The EntityManager offers a large number of methods to perform various queries. We will write methods to insert, fetch, update, and delete data in the PlayerRepository.
merge() method for INSERT and UPDATE queries
The EntityManager offers a merge() method for both INSERT and UPDATE operations. merge() checks if the primary key value is being passed to it or not. If it finds the primary key, it updates the corresponding record. If the primary key is not passed, it generates a value and inserts a new record in the table. The merge() method returns a Player object.
The logic of insertPlayer() and updatePlayer() methods will be the same. The difference lies in the arguments being passed to the merge() method.
public Player insertPlayer(Player player){return entityManager.merge(player);}public Player updatePlayer(Player player){return entityManager.merge(player);}
Defining the merge() method for INSERT and UPDATE queries
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