Hibernate -- use annotations to configure mappings, and hibernate -- Annotations

Hibernate -- use annotations to configure mappings, and hibernate -- Annotations

Preface:

　　You can configure the ing between object classes and databases in either of the following ways:

1. Use *. hbm. xml;

2. Use @ Annotation

　

I. annotation method:

1. @ Entity

Before the class, declare the class as a persistent class.

2. @ Table

Before the class, declare the associated table name for the class. If the table name and class name are the same, you can omit them.

Eg: @ Table (name = "tbl_role ")

　　

3. @ Proxy

Before the class, modify the category-level Indexing policy. The default value is delayed loading.

Eg: @ Proxy (lazy = false) // change to load now

 　

4. @ ID

Add it before the get/set Method of the primary key, or add it before the property to supplement the property:

@ GeneratedValue-primary key auto-increment policy,

@ GeneratedValue (Strategy = GenerationType. Auto). The default value is Auto.

Generally used with @ GenericGenerator:

Eg: @ GenaratedValue (generator = "native_name ")

@ GenericGenerator (name = "native_name", strategy = "native") // The primary key generation policy is native.

Note that the value of generator is consistent with that in name.

5. @ Column

If the attribute name and the corresponding database table column name are different, or the attribute name corresponding to the get/set method is not the column name, you need to add it before the get/set method, or add it before the attribute

Eg: @ Column (name = "RoleName ")

 

　　Association:

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6. @ ManyToOne -------- multi-to-one (foreign key) Association

Eg: @ ManyToOne (targetEntity = class_name.class)

@ JoinColumn (name = "c_name") // multiple pairs of foreign key column names

 

 

7. @ onetoworkflow -------- one-to-Multiple Association attributes

Eg: @ onetoty (targetEntity = class_name.class, mappedBy = "property_name", cascade = {CascadeType. ALL })

If the Set is not generic, you need to add targetEntity mappedBy to the attribute associated with targetEntity to maintain the foreign key relationship.

 

8. @ manytoyun-many-to-many

Eg: @ manytoty (targetEntity = Function. class)

@ JoinTable (name = "role_function_r", joinColumns = @ JoinColumn (name = "roleId"), inverseJoinColumns = @ JoinColumn (name = "functionId "))

In the figure (1), it indicates the name of the intermediate table with many-to-many relationships, and (2) it indicates the foreign key relationship between the intermediate table and the current object-class table. (3) indicates the foreign key relationship between the intermediate table and another table.

 

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9. @ Transcient

Add it before the get/set method, or add it before the property to declare the property does not need to be persisted.