Hibernate--Xxx.hbm.xml ORM metadata Table Object Relational mapping file

<?XML version= "1.0" encoding= "UTF-8"?><!DOCTYPE hibernate-mapping Public "-//hibernate/hibernate mapping DTD 3.0//en" "Http://www.hibernate.org/dtd/hib Ernate-mapping-3.0.dtd ">    <!--ORM Metadata Table Object Relational mapping file package: Configure the packages in the configuration file that are in the same class.  - <hibernate-mapping Package= "Com.itheima.a_hello" >       <!--class--Configuring entity-to-table relationships name: Fill in the full class name of the entity table: the name of the entity counterpart Dynamic-insert: Dynamic Insert default value is False true=> If the field value is NULL, do not participate in the INSERT statement dynamic-update: Dynamic update Default value "False" true=> not Changed properties will not be generated into the UPDATE statement -     <classname= "User"Table= "T_user"  >

              <!--id--configuration entity and the ID in the table the attribute name that identifies the primary key in the Name:user object column: The columns name of the primary key in the table length: The data length of the column            Unsaved-value (infrequently used): Specifies why a primary key is treated as NULL when the value is specified. Access (not recommended): field then when manipulating properties, the corresponding field is manipulated directly instead of the Get/set method -        <IDname= "id"column= "id"length= "255"   >


            <!--Generator-primary key generation strategy The 1.increment database generates its own primary key. First query the maximum ID value from the database, add the ID value 1 as the new primary key 2.iden                    Tity relies on the data's primary key auto-increment function 3.sequence sequence, which relies on the sequence function (Oracle) in the data. 4.hilo (pure Understanding, never used): Hibernate to implement the sequence of the algorithm itself, generate the primary key.                    (Hilo algorithm) 5.native automatically according to the database judgment, three select one. Identity|sequence|hilo 6.uuid generates a 32-bit non-repeating random string as the primary key 7.assigned itself specifying the primary key value.             Used when the primary key of a table is a natural primary key.  -            <Generatorclass= "UUID"></Generator>        </ID>     

        <!--Property-The attribute in the entity corresponds to the column in the table name: attribute name in entity column: Name of column in table length: Data length             Precision: Precision scale After decimal point: number of significant digits insert (not normally used): whether the property joins the INSERT statement.             Update (not normally used): whether this property joins the UPDATE statement. Not-null: Specifies whether the constraint of a property uses a non-null unique: Specifies whether the constraint of the specified property uses a unique -         <!--type: Expression of this property can be specified in three ways properties Java type Database type specify Hibernate class TYPE specifies java.lang.String varchar String -        < Propertyname= "Name"column= "Name"Update= "true"type= "string" ></ Property>        < Propertyname= "Password"column= "Password"></ Property>         < Propertyname= "Sal"column= "Sal"Precision= "2" Scale= "3" ></ Property>     </class> </hibernate-mapping>

Hibernate--Xxx.hbm.xml ORM metadata Table Object Relational mapping file