there is a set collection of tag classes in the user class; maintain relationships only from the user class, one-to-many @ OneToMany @JoinTable(name="shuo_tag", inverseJoinColumns=@JoinColumn(name="tag_id"), jo...

https: github.com thymeleaf . I use jpa, to cascade the two classes through annotations. in the html page, when you get the object of any class through the thymeleaf tag, it will appear . java.lang.StackOverflowError: null at sun.reflect.misc.Refl...

one class @Entity public class Shuo{ @Id @GeneratedValue private int id; private String title; private Date date; String content; @ManyToOne(cascade = CascadeType.REFRESH) @JoinColumn(name = "user_id") private User user; : @OneT...

this is a question post with nothing to do, the problem encountered by the beginner of programming, there is no solution, I do not know which seniors have ideas, but also hope to give me some advice. is like this The project uses spring-data-jpa as ...

anyone who has used oracle knows that the self-increasing id, of oracle is usually implemented by sequence. I only marked @ Id, on the entity and did not mark it to other additional comments. I thought there would be an error in save, but it actually ...

I am a novice in database. Recently, when using spring-data-jpa, I encountered the problem that I could not design entity classes according to the Emurr model, so I asked a question. Emurr model is shown in the following figure: consider Company a...

Code first: entity class: @Entity @Table(name = "joinTable_a") public class JoinTableA { @Id @GeneratedValue private long id; private String name; @OneToOne @JoinTable(name = "join_a2b", joinColumns = @JoinColumn(n...

how to set the query intercepting query for mongotemplate in spring data jpa, and then modify the query statement before submitting the query. Just like the interceptor in hibernate. Now you need to intercept all MongoDBtemplate query requests. ...

in the use of Spring Data JPA, we often use the save method instead of updating. Doing so updates all fields, even the empty fields in the object, resulting in data loss. Although, JPA provides my own way to write SQL, but for updates, if I only want to ...

1. Due to the need to query the two code,name fields in the entity table, Baidu said that it can customize the query entity class, such as: public class Entity implements Serializable(){ String code ; String name ; ... public Entity (St...

< H2 > demand < H2 > what I want to do is to trigger (.size) lazily load all the data of the associated table when needed, do not load the data of the associated table when not needed, and do whatever I want. < H2 > question < H2 > my table entity...

suppose I create a new user with four fields, id, user name, password, and address. how does spring data jpa query only the username and password fields? (the actual developed table has more than 20 fields, and it takes 12 seconds for a query to return...

[actual phenomenon] long-term use of MyBatis, tools using Mybatis (Mybatis Generator generic Mapper), can have methods like insertSelective (E). is actually mapped as follows: SQL (many fields have default values, but only part of the value is neede...

@Modifying @Query(value = "insert into role_account (role_id,account_id) values ", nativeQuery = true) Integer insertUserRealtion (Long roleId, List<Long> userIds); as above, how to express after values? ...

how does SpringDataJpa call a stored procedure without an OUT parameter through Repository? this is how my stored procedure is defined @Entity @NamedStoredProcedureQuery( name = "Markets.nearById", procedureName = "near...

query conditions are composed of String and List, such as: (List < String > id, String location, String status,.) The exact number of fields in the parameter is not certain. There may be more than one . how to implement this situation? you d better ...

entity 1 inherits another entity 2. Entity 2 is a public entity with id,createDate and other common attributes, so entity 1 does not need to write these fields, but the table cannot be built, and an error is reported: Error starting ApplicationContext....

mysql is @ Column (name = "name ", columnDefinition = "varchar (100) comment comment ) what does postgresql do? ...

I use the save method to save the object and get the object returned by the save method. The data of the joined object is empty when I save, I set the id of the associated beComment I thought I could return the beComment data completely when I re...

I opened the sql log, and found that the find method was executed after the save was executed, but not the sql. if find is executed directly, sql will be executed Why is this? what is the principle? there is no explanation on the official website. ...