我正在學習 Spring-Data-REST 并且遇到了涉及我的注釋的障礙。目前我有以下架構：create table user( ID int NOT NULL auto_increment, NAME VARCHAR(60) NOT NULL, PASS VARCHAR(20) NOT NULL, primary key (ID));create table recipe( ID int NOT NULL auto_increment, NAME varchar(60) NOT NULL, USER_ID int NOT NULL, primary key (ID), FOREIGN KEY (USER_ID) REFERENCES user(ID) ON DELETE CASCADE);create table ingredient( ID int not null auto_increment, NAME varchar(60) not null, primary key(ID));create table ingredientsList ( ID int NOT NULL auto_increment, NAME varchar(60) NOT NULL, RECIPE_ID int not null, INGREDIENT_ID int not null, QUANTITY int not null, primary key (ID), foreign key (RECIPE_ID) REFERENCES recipe(ID) on delete cascade, foreign key (INGREDIENT_ID) references ingredient(ID) on delete cascade);create table direction( ID int NOT NULL auto_increment, NAME varchar(60) NOT NULL, RECIPE_ID int not null, STEP int not null, DESCRIPTION varchar(256), primary key (ID), foreign key (RECIPE_ID) REFERENCES recipe(ID) on delete cascade);我的 Spring Data REST API 中表示了每個表，除了一個表，即成分列表表。這是我當前的實現，當我運行 .\mvn clean install 時無法正常工作：import java.util.Objects;import java.util.Set;import javax.persistence.Column;import javax.persistence.CascadeType;import javax.persistence.Entity;import javax.persistence.FetchType;import javax.persistence.JoinColumn;import javax.persistence.ManyToOne;import javax.persistence.OneToMany;@Entitypublic class IngredientsList extends AbstractEntity { @ManyToOne(fetch = FetchType.EAGER) @JoinColumn(nullable=false) private Recipe recipe; @OneToMany(mappedBy = "ingredientsList", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true) private Set<Ingredient> ingredients; @Column(nullable = false) private Long quantity; public Recipe getRecipe() { return recipe; } public void setRecipe(Recipe recipe){ this.recipe = recipe; }
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TA貢獻1810條經驗 獲得超5個贊
您@OneToMany對IngredientsList類的注釋暗示類中應該有一個ingredientsList字段Ingredient，而實際上沒有。在您的架構中，您INGREDIENT_ID的ingredientsList表中有一個字段，這意味著 anIngredientsList只能有一個Ingredient.
我認為你的意思是IngredientsList有很多Ingredient孩子，這意味著ingredient表應該有一個INGREDIENT_LIST_ID字段作為ingredientsList表的外鍵，并且Ingredients類應該有一個ingredientsList字段。該INGREDIENT_ID字段應該從ingredientsList表中刪除。
如果一個IngredientsList應該只有一個Ingredient，那么改變
@OneToMany(mappedBy = "ingredientsList", fetch = FetchType.EAGER, cascade = CascadeType.ALL, orphanRemoval = true)
private Set<Ingredient> ingredients;
到
@ManyToOne
@JoinColumn("ingredient_id")
private Ingredient ingredient
根據需要添加cascade和orphanRemoval。@ManyToOne默認情況下，A應該急切地獲取連接的數據。
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