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Hibernate4一对多关系映射
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示例：一個類別（Category）下面有多個商品（Product），多個商品對應(yīng)對應(yīng)同一類別
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Java代碼 ?
public?class?Category?{???????????private?Integer?id;??????private?String?name;??????private?Set<Product>?products?=?new?HashSet<Product>();??????????}?????
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Java代碼 ?
public?class?Product?{????????private?Integer?id;??????private?String?name;??????private?Double?price;??????private?Category?category;??????????????}??
用XML映射
Xml代碼 ?
<hibernate-mapping?package="org.monday.hibernate4.domain">??????<class?name="Category"?table="tbl_category">??????????<id?name="id">??????????????<generator?class="identity"?/>??????????</id>??????????<property?name="name"?/>??????????<set?name="products"?inverse="true">??????????????<key?column="category_id"?/>??????????????<one-to-many?class="Product"?/>??????????</set>??????</class>??</hibernate-mapping>??
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Xml代碼 ?
<hibernate-mapping?package="org.monday.hibernate4.domain">??????<class?name="Product"?table="tbl_product">??????????<id?name="id">??????????????<generator?class="identity"?/>??????????</id>??????????<property?name="name"?/>??????????<property?name="price"?/>??????????<many-to-one?name="category"?class="Category"???????????????column="category_id"?not-null="true"/>??????</class>??</hibernate-mapping>??
?用@Annotation映射
Java代碼 ?
@Entity??@Table(name?=?"tbl_category")??public?class?Category?{????????@Id??????@GeneratedValue(strategy?=?GenerationType.IDENTITY)??????private?Integer?id;??????private?String?name;????????????????@OneToMany(mappedBy?=?"category")??????private?Set<Product>?products?=?new?HashSet<Product>();??????????}?????
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Java代碼 ?
@Entity??@Table(name?=?"tbl_product")??public?class?Product?{????????@Id??????@GeneratedValue(strategy?=?GenerationType.IDENTITY)??????private?Integer?id;??????private?String?name;??????private?Double?price;????????@ManyToOne??????@JoinColumn(name?=?"category_id",?nullable?=?false)??????private?Category?category;??????????}?????
?測試代碼
Java代碼 ?
Product?p?=?new?Product();??p.setName("hibernate");??p.setPrice(99.9);????Category?c?=?new?Category();??c.setName("book");??c.getProducts().add(p);????p.setCategory(c);????session.save(c);???session.save(p);??
? SQL schema
Sql代碼 ?
Hibernate:???????create?table?tbl_category?(??????????id?integer?not?null?auto_increment,??????????name?varchar(255),??????????primary?key?(id)??????)??Hibernate:???????create?table?tbl_product?(??????????id?integer?not?null?auto_increment,??????????name?varchar(255),??????????price?double?precision,??????????category_id?integer,??????????primary?key?(id)??????)??Hibernate:???????alter?table?tbl_product???????????add?index?FK2BA956E5535EE4C?(category_id),???????????add?constraint?FK2BA956E5535EE4C???????????foreign?key?(category_id)???????????references?tbl_category?(id)??Hibernate:???????insert???????into??????????tbl_category??????????(name)???????values??????????(?)??Hibernate:???????insert???????into??????????tbl_product??????????(name,?price,?category_id)???????values??????????(?,??,??)????
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