Hibernate Tutorial

HIBERNATE TUTORIAL

HIBERNATE - Introduction to Hibernate

Hibernate is an open source object/relational mapping tool for Java. Hibernate lets you develop persistent classes following common Java idiom - including association, inheritance, polymorphism, composition and the Java collections framework.

Hibernate not only takes care of the mapping from Java classes to database tables (and from Java data types to SQL data types), but also provides data query and retrieval facilities and can significantly reduce development time otherwise spent with manual data handling in SQL and JDBC.

Hibernates goal is to relieve the developer from 95 percent of common data persistence related programming tasks.

Hibernate is Free Software. The LGPL license is sufficiently flexible to allow the use of Hibernate in both open source and commercial projects (see the LicenseFAQ for details). Hibernate is available for download at http://www.hibernate.org/. This tutorial aims to provide insight into Hibernate version 3.0RC and its usage

Some of the main features of hibernate are listed below and we have tried to explain some of them in detail later in this tutorial.

Transparent persistence without byte code processing Transparent persistence JavaBeans style properties are persisted No build-time source or byte code generation / processing Support for extensive subset of Java collections API Collection instance management Extensible type system Constraint transparency Automatic Dirty Checking Detached object support Object-oriented query language Powerful object-oriented query language Full support for polymorphic queries New Criteria queries Native SQL queries Object / Relational mappings Three different O/R mapping strategies Multiple-objects to single-row mapping Polymorphic associations Bidirectional associations Association filtering Collections of basic types Indexed collections Composite Collection Elements Lifecycle objects Automatic primary key generation

Multiple synthetic key generation strategies Support for application assigned identifiers Support for composite keys Object/Relational mapping definition XML mapping documents Human-readable format XDoclet support HDLCA (Hibernate Dual-Layer Cache Architecture) Thread safeness Non-blocking data access Session level cache Optional second-level cache Optional query cache Works well with others High performance Lazy initialization Outer join fetching Batch fetching Support for optimistic locking with versioning/timestamping Highly scalable architecture High performance No "special" database tables SQL generated at system initialization time (Optional) Internal connection pooling and PreparedStatement caching J2EE integration JMX support Integration with J2EE architecture (optional) New JCA support

Hibernate

High level architecture of Hibernate can be described as shown in following illustration.

Hibernate makes use of persistent objects commonly called as POJO (POJO = "Plain Old Java Object".) along with XML mapping documents for persisting objects to the database layer. The term POJO refers to a normal Java objects that does not serve any other special role or implement any special interfaces of any of the Java frameworks (EJB, JDBC, DAO, JDO, etc...).

Rather than utilize byte code processing or code generation, Hibernate uses runtime reflection to determine the persistent properties of a class. The objects to be persisted are defined in a mapping document, which serves to describe the persistent fields and associations, as well as any subclasses or proxies of the persistent object. The mapping documents are compiled at application startup time and provide the framework with necessary information for a class. Additionally, they are used in support operations, such as generating the database schema or creating stub Java source files.

Typical Hibernate code

sessionFactory = new Configuration().configure().buildSessionFactory();

Session session = sessionFactory.openSession();

Transaction tx = session.beginTransaction();

Customer newCustomer = new Customer();newCustomer.setName("New Customer");newCustomer.setAddress("Address of New Customer");

newCustomer.setEmailId("[email protected]");

session.save(newCustomer);

tx.commit();

session.close();

First step is hibernate application is to retrieve Hibernate Session; Hibernate Session is the main runtime interface between a Java application and Hibernate. SessionFactory allows applications to create hibernate session by reading hibernate configurations file hibernate.cfg.xml.

After specifying transaction boundaries, application can make use of persistent java objects and use session for persisting to the databases.

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HIBERNATE - Features of Hibernate

Transparent persistence without byte code processing Transparent persistence JavaBeans style properties are persisted No build-time source or byte code generation / processing Support for extensive subset of Java collections API Collection instance management Extensible type system Constraint transparency Automatic Dirty Checking Detached object support Object-oriented query language Powerful object-oriented query language Full support for polymorphic queries New Criteria queries Native SQL queries Object / Relational mappings Three different O/R mapping strategies Multiple-objects to single-row mapping

Polymorphic associations Bidirectional associations Association filtering Collections of basic types Indexed collections Composite Collection Elements Lifecycle objects Automatic primary key generation Multiple synthetic key generation strategies Support for application assigned identifiers Support for composite keys Object/Relational mapping definition XML mapping documents Human-readable format XDoclet support HDLCA (Hibernate Dual-Layer Cache Architecture) Thread safeness Non-blocking data access Session level cache Optional second-level cache Optional query cache Works well with others High performance Lazy initialization Outer join fetching Batch fetching Support for optimistic locking with versioning/timestamping Highly scalable architecture High performance No "special" database tables SQL generated at system initialization time (Optional) Internal connection pooling and PreparedStatement caching J2EE integration JMX support Integration with J2EE architecture (optional) New JCA supportHIBERNATE TUTORIAL

HIBERNATE - Getting Started With Hibernate

Hibernate is Free Software. The LGPL license is sufficiently flexible to allow the use of Hibernate in both open source and commercial projects (see the LicenseFAQ for details). Hibernate is available for download at http://www.hibernate.org/

We wll take up an simple java example that authenticates users based on the credentials to get started with hibernate.

HIBERNATE TUTORIAL


Preparing Database

Let’s consider a simple database schema with a singe table as APPLABSUSER.

CREATE TABLE àpplabsuser` (ÙSER_ID` int(11) NOT NULL default '0',ÙSER_NAME` varchar(255) NOT NULL default '',ÙSER_PASSWORD` varchar(255) NOT NULL default '',ÙSER_FIRST_NAME` varchar(255) default NULL,ÙSER_LAST_NAME` varchar(255) default NULL,ÙSER_EMAIL` varchar(255) default NULL,ÙSER_CREATION_DATE` date default NULL,ÙSER_MODIFICATION_DATE` date default NULL,PRIMARY KEY (ÙSER_ID`),UNIQUE KEY ÙSER_NAME` (ÙSER_NAME`)) ;

HIBERNATE TUTORIAL


Creating persistent java objects

Hibernate works best with the Plain Old Java Objects programming model for persistent classes.

Hibernate is not restricted in its usage of property types, all Java JDK types and primitives (like String, char and Date) can be mapped, including classes from the Java collections framework. You can map them as values, collections of values, or associations to other entities. The id is a special property that represents the database identifer (primary key) of that class, Hibernate can use identifiers only internally, but we would lose some of the flexibility in our application architecture.

No special interface has to be implemented for persistent classes nor do you have to subclass from a special root persistent class. Hibernate also doesn't require any build time processing, such as byte-code manipulation, it relies solely on Java reflection and runtime class enhancement (through CGLIB). So, without any dependency of the POJO class on Hibernate, we can map it to a database table.

Following code sample represents a java object structure which represents the AppLabsUser table. Generally these domain objects contain only getters and setters methods. One can use Hibernate extension toolset to create such domain objects.

AppLabsUser.java

package org.applabs.quickstart;

import java.io.Serializable;import java.util.Date;import org.apache.commons.lang.builder.ToStringBuilder;

public class AppLabsUser implements Serializable {

public void setName(String name) {/** identifier field */private Long id;

/** persistent field */private String userName;

/** persistent field */private String userPassword;

/** persistent field */private String userFirstName;

/** persistent field */private String userLastName;

/** persistent field */private String userEmail;

/** persistent field */private Date userCreationDate;

/** persistent field */private Date userModificationDate;

/** full constructor */public Applabsuser(String userName, String userPassword, String userFirstName, String userLastName, String userEmail, Date userCreationDate, Date userModificationDate) {this.userName = userName;this.userPassword = userPassword;this.userFirstName = userFirstName;this.userLastName = userLastName;this.userEmail = userEmail;this.userCreationDate = userCreationDate;this.userModificationDate = userModificationDate;}

/** default constructor */public Applabsuser() {}

public Long getId() {return this.id;}

public void setId(Long id) {this.id = id;}

public String getUserName() {return this.userName;}

public void setUserName(String userName) {this.userName = userName;}

public String getUserPassword() {return this.userPassword;}

public void setUserPassword(String userPassword) {this.userPassword = userPassword;}

public String getUserFirstName() {return this.userFirstName;}

public void setUserFirstName(String userFirstName) {this.userFirstName = userFirstName;}

public String getUserLastName() {return this.userLastName;}

public void setUserLastName(String userLastName) {this.userLastName = userLastName;}

public String getUserEmail() {return this.userEmail;}

public void setUserEmail(String userEmail) {this.userEmail = userEmail;}

public Date getUserCreationDate() {return this.userCreationDate;}

public void setUserCreationDate(Date userCreationDate) {this.userCreationDate = userCreationDate;}

public Date getUserModificationDate() {return this.userModificationDate;}

public void setUserModificationDate(Date userModificationDate) {this.userModificationDate = userModificationDate;}public String toString() {return new ToStringBuilder(this).append("id", getId()).toString();}

}// End of class

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Mapping POJO with persistence layer using hibernate mapping document

Each persistent class needs to be mapped with its configuration file. Following code represents Hibernate mapping file for AppLabsUser class.

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 2.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd"><hibernate-mapping>

<class name="org.applabs.hibernate.quickstart.AppLabsUser" table="applabsuser">

<id column="USER_ID" name="id" type="java.lang.Long">

<generator class="sequence"/>

</id>

<property column="USER_NAME" length="255" name="userName" not-null="true" type="java.lang.String"/><property column="USER_PASSWORD" length="255" name="userPassword" not-null="true" type="java.lang.String"/><property column="USER_FIRST_NAME" length="255" name="userFirstName" type="java.lang.String"/><property column="USER_LAST_NAME" length="255" name="userLastName" type="java.lang.String"/><property column="USER_EMAIL" length="255" name="userEmail" type="java.lang.String"/><property column="USER_CREATION_DATE" length="10" name="userCreationDate" type="java.util.Date"/><property column="USER_MODIFICATION_DATE" length="10" name="userModificationDate" type="java.util.Date"/>

</class>

</hibernate-mapping>

One can also generate Hibernate mapping documents using Hibernate extension toolset. Hibernate mapping documents are straight forward. The <class> element maps a table with corresponding class. The <id> element represents the primary key column, and its associated attribute in the domain object. The <property> elements represent all other attributes available in the domain object. HIBERNATE TUTORIAL


Hibernate Configuration File

Hibernate configuration file information needed to connect to persistent layer and the linked mapping documents. You can either specify the data source name or JDBC details that are required for hibernate to make JDBC connection to the database. The element <mapping-resource> refers to the mapping document that contains mapping for domain object and hibernate mapping

document.

<!DOCTYPE hibernate-configuration PUBLIC"-//Hibernate/Hibernate Configuration DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<property name="show_sql">true</property><property name="hibernate.dialect">org.hibernate.dialect.MySQLMyISAMDialect</property><property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property><property name="hibernate.connection.url">jdbc:mysql://localhost:3306/applabs</property><property name="hibernate.connection.username">root</property><property name="hibernate.connection.password">r00Tp@$wd</property>

<mapping resource="org/applabs/hibernate/quickstart/Applabsuser.hbm.xml"/> </session-factory></hibernate-configuration> HIBERNATE TUTORIAL


Hibernate Configuration File

Hibernate configuration file information needed to connect to persistent layer and the linked mapping documents. You can either specify the data source name or JDBC details that are required for hibernate to make JDBC connection to the database. The element <mapping-resource> refers to the mapping document that contains mapping for domain object and hibernate mapping document.

<!DOCTYPE hibernate-configuration PUBLIC"-//Hibernate/Hibernate Configuration DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<property name="show_sql">true</property><property name="hibernate.dialect">org.hibernate.dialect.MySQLMyISAMDialect</property><property name="hibernate.connection.driver_class">org.gjt.mm.mysql.Driver</property><property name="hibernate.connection.url">jdbc:mysql://localhost:3306/applabs</property><property name="hibernate.connection.username">root</property><property name="hibernate.connection.password">r00Tp@$wd</property>

<mapping resource="org/applabs/hibernate/quickstart/Applabsuser.hbm.xml"/> </session-factory></hibernate-configuration> HIBERNATE TUTORIAL


Hibernate Sample Code (Inserting new record)

Here is how you can use Hibernate in your programs. Typical Hibernate programs begin with configuration that is required for Hibernate. Hibernate can be configured in two ways. Programmatically and Configuration file based. In Configuration file based mode, hibernate looks for configuration file “hibernate.cfg.xml” in the claspath. Based on the resource mapping provided hibernate creates mapping of tables and domain objects. In the programmatic configuration method, the details such as JDBC connection details and resource mapping details etc are supplied in the program using Configuration API.

Following example shows programmatic configuration of hibernate.

Configuration config = new Configuration().addResource("org/applabs/hibernate/quickstart/Applabsuser.hbm.xml")Configuration config = new Configuration().addClass(org.hibernate.quickstart.Applabsuser.class).setProperty("hibernate.dialect", "org.hibernate.dialect. MySQLMyISAMDialect").setProperty("hibernate.connection.driver_class", " org.gjt.mm.mysql.Driver"). . . SessionFactory sessions = config.buildSessionFactory();

In configuration file based approach, “hibernate.cfg.xml” is placed in the classpath, Following Hibernate code can be used in this method.

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();Session session = sessionFactory.openSession();AppLabsUser user = new AppLabsUser();Transaction tx = session.beginTransaction();user.setUserCreationDate(new Date());user.setUserEmail("[email protected]");user.setUserFirstName("userFirstName");user.setUserLastName("userLastName");user.setUserName("userName-1");user.setUserPassword("userPassword");session.saveOrUpdate(user);tx.commit();session.close();


Hibernate Sample Code (Quering the database)

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();Session session = sessionFactory.openSession(); ArrayList arrayList = null;

String SQL_STRING = "FROM AppLabsUser as users";Query query = session.createQuery(SQL_STRING);ArrayList list = (ArrayList)query.list();

for(int i=0; i<list.size();i++){System.out.println(list.get(i));}

session.close();

HIBERNATE - Hibernate O/R Mapping

This section will explain how to write the mapping documents manually. Although there are tools available to create these mapping documents, learning how to create these documents manually helps in fine tuning and setting up advance table mapping.

Mapping Declaration

Object/relational mappings are usually defined in XML document. The mapping language is Java-centric, meaning that mappings are constructed around persistent class declarations, not table declarations.

Mapping Document<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping package="org.somepackage.eg">

<class name="Foo" table=”FooTable”>

<id name="id" type=”java.lang.Long”> <generator class=”sequence”/> </id> </class></hibernate-mapping>

The above example shows a typical mapping document that contains class mapping with table.All mapping XML document should refer to hibernate-mapping-3.0.dtd via doctype.

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<class> element

The <Class> element maps the domain object with corresponding entity in the database. hibernate-mapping element allows you to nest several persistent <class> mappings, as shown above. It is however good practice to map only a single persistent class in one mapping file and name it after the persistent superclass, e.g. User.hbm.xml, Group.hbm.xml.

<class

name="ClassName"table="tableName"discriminator-value="discriminator_value" mutable="true|false" schema="owner" catalog="catalog"proxy="ProxyInterface" dynamic-update="true|false" dynamic-insert="true|false" select-before-update="true|false" polymorphism="implicit|explicit" where="arbitrary sql where condition" persister="PersisterClass" batch-size="N" optimistic-lock="none|version|dirty|all" lazy="true|false" entity-name="EntityName" catalog="catalog" check="arbitrary sql check condition" rowid="rowid" subselect="SQL expression" abstract="true|false"

(1)(2)(3)(4)(5)(6)(7) (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)

/>

(1) name (optional): The fully qualified Java class name of the persistent class (or interface). If this attribute is missing, it is assumed that the mapping is for a non-POJO entity.

(2) table (optional - defaults to the unqualified class name): The name of its database table. (3) discriminator-value (optional - defaults to the class name): A value that distiguishes individual subclasses, used

for polymorphic behaviour. Acceptable values include null and not null. (4) mutable (optional, defaults to true): Specifies that instances of the class are (not) mutable. (5) schema (optional): Override the schema name specified by the root <hibernate-mapping> element. (6) catalog (optional): Override the catalog name specified by the root <hibernate-mapping> element. (7) proxy (optional): Specifies an interface to use for lazy initializing proxies. You may specify the name of the class

itself.

(8) dynamic-update (optional, defaults to false): Specifies that UPDATE SQL should be generated at runtime and contain only those columns whose values have changed.

(9) dynamic-insert (optional, defaults to false): Specifies that INSERT SQL should be generated at runtime and contain only the columns whose values are not null.

(10) select-before-update (optional, defaults to false): Specifies that Hibernate should never perform an SQL UPDATE unless it is certain that an object is actually modified. In certain cases (actually, only when a transient object has been associated with a new session using update()), this means that Hibernate will perform an extra SQL SELECT to determine if an UPDATE is actually required.

(11) polymorphism (optional, defaults to implicit): Determines whether implicit or explicit query polymorphism is used.

(12)where (optional) specify an arbitrary SQL WHERE condition to be used when retrieving objects of this class

(13)persister (optional): Specifies a custom ClassPersister.

(14)batch-size (optional, defaults to 1) specify a "batch size" for fetching instances of this class by identifier.

(15)optimistic-lock (optional, defaults to version): Determines the optimistic locking strategy.

(16)lazy (optional): Lazy fetching may be completely disabled by setting lazy="false".

(17) entity-name (optional): Hibernate3 allows a class to be mapped multiple times (to different tables, potentially), and allows entity mappings that are represented by Maps or XML at the java level. In these cases, you should provide an explicit arbitrary name for the entity. See Section 4.4, “Dynamic models” for more information.

(18)catalog (optional): The name of a database catalog used for this class and its table.

(19) check (optional): A SQL expression used to generate a multi-row check constraint for automatic schema generation.

(20) rowid (optional): Hibernate can use so called ROWIDs on databases which support. E.g. on Oracle, Hibernate can use the rowid extra column for fast updates if you set this option to rowid. A ROWID is an implementation detail and represents the physical location of a stored tuple.

(21) subselect (optional): Maps an immutable and read-only entity to a database subselect. Useful if you want to have a view instead of a base table, but don't. See below for more information.

(22)abstract (optional): Used to mark abstract superclasses in <union-subclass> hierarchies.

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<id> element The <id> element defines the mapping from that property to the primary key column. Mapped classes must declare the primary key column of the database table. Most classes will also have a JavaBeans-style property holding the unique identifier of an instance.

<id

name="propertyName" type="typename" column="column_name" unsaved-value="null|any|none|undefined|id_value" access="field|property|ClassName">

<generator class="generatorClass"/>

(1)(2)(3)(4)(5)

/>

(1) name (optional): The name of the identifier property. (2) type (optional): A name that indicates the Hibernate type. (3) column (optional - defaults to the property name): The name of the primary key column. (4) unsaved-value (optional - defaults to a "sensible" value): An identifier property value that indicates that an

instance is newly instantiated (unsaved), distinguishing it from detached instances that were saved or loaded in a previous session.

(5) access (optional - defaults to property): The strategy Hibernate should use for accessing the property value.


<generator> element

The optional <generator> child element names a Java class used to generate unique identifiers for instances of the persistent class. If any parameters are required to configure or initialize the generator instance, they are passed using the <param> element.

<id name="id" type="long" column="cat_id">

<generator class="org.hibernate.id.TableHiLoGenerator">

<param name="table">uid_table</param><param name="column">next_hi_value_column</param>

</generator>

</id>

All generators implement the interface org.hibernate.id.IdentifierGenerator. This is a very simple interface; some applications may choose to provide their own specialized implementations. However, Hibernate provides a range of built-in implementations. There are shortcut names for the built-in generators:

increment generates identifiers of type long, short or int that are unique only when no other process is inserting data into the same table. Do not use in a cluster. .

identity supports identity columns in DB2, MySQL, MS SQL Server, Sybase and HypersonicSQL. The returned identifier is of type long, short or int.

sequence uses a sequence in DB2, PostgreSQL, Oracle, SAP DB, McKoi or a generator in Interbase. The returned identifier is of type long, short or int

hilo uses a hi/lo algorithm to efficiently generate identifiers of type long, short or int, given a table and column (by default hibernate_unique_key and next_hi respectively) as a source of hi values. The hi/lo algorithm generates identifiers that are unique only for a particular database.

seqhilo uses a hi/lo algorithm to efficiently generate identifiers of type long, short or int, given a named database sequence.

uuid uses a 128-bit UUID algorithm to generate identifiers of type string, unique within a network (the IP address is used). The UUID is encoded as a string of hexadecimal digits of length 32.

guid uses a database-generated GUID string on MS SQL Server and MySQL. native picks identity, sequence or hilo depending upon the capabilities of the underlying database. assigned lets the application to assign an identifier to the object before save() is called. This is the default strategy if no

<generator> element is specified. select retrieves a primary key assigned by a database trigger by selecting the row by some unique key and retrieving

the primary key valueforeign uses the identifier of another associated object. Usually used in conjunction with a <one-to-one> primary key

association.


<property> element

The <property> element declares a persistent, JavaBean style property of the class.

<property

name="propertyName" column="column_name"type="typename" update="true|false" insert="true|false" formula="arbitrary SQL expression" access="field|property|ClassName"lazy="true|false" unique="true|false" not-null="true|false" optimistic-lock="true|false"

(1)(2)(3)(4)(4)(5)(6)(7) (8)(9)(10)

/>

All generators implement the interface org.hibernate.id.IdentifierGenerator. This is a very simple interface; some applications may choose to provide their own specialized implementations. However, Hibernate provides a range of built-in implementations. There are shortcut names for the built-in generators:

(1) name: the name of the property, with an initial lowercase letter. (2) column (optional - defaults to the property name): the name of the mapped database table column. This may also be

specified by nested <column> element(s). (3) type (optional): a name that indicates the Hibernate type. (4) update, insert (optional - defaults to true) : specifies that the mapped columns should be included in SQL UPDATE and/or

INSERT statements. Setting both to false allows a pure "derived" property whose value is initialized from some other property that maps to the same colum(s) or by a trigger or other application.

(5) formula (optional): an SQL expression that defines the value for a computed property. Computed properties do not have a column mapping of their own.

(6) access (optional - defaults to property): The strategy Hibernate should use for accessing the property value. (7) lazy (optional - defaults to false): Specifies that this property should be fetched lazily when the instance variable is first

accessed (requires build-time bytecode instrumentation).

(8) unique (optional): Enable the DDL generation of a unique constraint for the columns. Also, allow this to be the target of a property-ref.

(9)not-null (optional): Enable the DDL generation of a nullability constraint for the columns.

(10) optimistic-lock (optional - defaults to true): Specifies that updates to this property do or do not require acquisition of the optimistic lock. In other words, determines if a version increment should occur when this property is dirty.

typename could be:

The name of a Hibernate basic type (eg. integer, string, character, date, timestamp, float, binary, serializable, object, blob).

The name of a Java class with a default basic type (eg. int, float, char, java.lang.String, java.util.Date, java.lang.Integer, java.sql.Clob).

The name of a serializable Java class.

The class name of a custom type (eg. com.illflow.type.MyCustomType).

An especially powerful feature are derived properties. These properties are by definition read-only, the property value is computed at load time. You declare the computation as a SQL expression, this translates to a SELECT clause subquery in the SQL query that loads an instance:

<property name="totalPrice"formula="( SELECT SUM (li.quantity*p.price) FROM LineItem li, Product p

WHERE li.productId = p.productIdAND li.customerId = customerIdAND li.orderNumber = orderNumber )"/>

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<many-to-one> element

An ordinary association to another persistent class is declared using a many-to-one element. The relational model is a many-to-one association: a foreign key in one table is referencing the primary key column(s) of the target table.

<many-to-one

name="propertyName" column="column_name" class="ClassName" cascade="cascade_style" fetch="join|select" update="true|false"insert="true|false" property-ref="propertyNameFromAssociatedClass"access="field|property|ClassName"unique="true|false"not-null="true|false" optimistic-lock="true|false"lazy="true|false" entity-name="EntityName"

(1)(2)(3)(4)(5)(6)(6)(7) (8)(9)(10)(11) (12)

/>

(1) name: The name of the property. (2) column (optional): The name of the foreign key column. This may also be specified by nested <column>

element(s). (3) class (optional - defaults to the property type determined by reflection): The name of the associated class. (4) cascade (optional): Specifies which operations should be cascaded from the parent object to the associated

object. (5) join (optional - defaults to select): Chooses between outer-join fetching or sequential select fetching. (6) update, insert (optional - defaults to true) specifies that the mapped columns should be included in SQL UPDATE

and/or INSERT statements. Setting both to false allows a pure "derived" association whose value is initialized from some other property that maps to the same colum(s) or by a trigger or other application.

(7) property-ref: (optional) The name of a property of the associated class that is joined to this foreign key. If not specified, the primary key of the associated class is used.

(8)access (optional - defaults to property): The strategy Hibernate should use for accessing the property value.

(9) unique (optional): Enable the DDL generation of a unique constraint for the foreign-key column. Also, allow this to be the target of a property-ref. This makes the association multiplicity effectively one to one.

(10)not-null (optional): Enable the DDL generation of a nullability constraint for the foreign key columns.

(11) optimistic-lock (optional - defaults to true): Specifies that updates to this property do or do not require acquisition of the optimistic lock. In other words, dertermines if a version increment should occur when this property is dirty.

(12) lazy (optional - defaults to false): Specifies that this property should be fetched lazily when the instance variable is first accessed (requires build-time bytecode instrumentation).

A typical many-to-one declaration looks as simple as this:

<many-to-one name="product" class="Product" column="PRODUCT_ID"/>


<one-to-one> element

A one-to-one association to another persistent class is declared using a one-to-one element. .

<one-to-one

name="propertyName" (1)class="ClassName" (2)cascade="cascade_style" (3)constrained="true|false" (4)fetch="join|select" (5)property-ref="propertyNameFromAssociatedClass" (6)access="field|property|ClassName" (7)formula="any SQL expression" (8)entity-name="EntityName"

(1)(2)(3)(4)(5)(6)(7) (8)

/>

(1) name: The name of the property. (2) class (optional - defaults to the property type determined by reflection): The name of the associated class. (3) cascade (optional) specifies which operations should be cascaded from the parent object to the associated object. (4) constrained (optional) specifies that a foreign key constraint on the primary key of the mapped table references the table

of the associated class. This option affects the order in which save() and delete() are cascaded, and determines whether the association may be proxied (it is also used by the schema export tool).

(5) fetch (optional - defaults to select): Chooses between outer-join fetching or sequential select fetching. (6) property-ref: (optional) The name of a property of the associated class that is joined to the primary key of this class. If

not specified, the primary key of the associated class is used. (7)

access (optional - defaults to property): The strategy Hibernate should use for accessing the property value.

(8) formula (optional): Almost all one to one associations map to the primary key of the owning entity. In the rare case that this is not the case, you may specify a some other column, columns or expression to join on using an SQL formula. (See org.hibernate.test.onetooneformula for an example.)

A typical many-to-one declaration looks as simple as this:

<many-to-one name="product" class="Product" column="PRODUCT_ID"/>

HIBERNATE - Hibernate Mapping In Depth

Hibernate allows the mapping of Mapped tables with the domain objects using the persistent collection-valued fields. These fields needs be declared as an interface type. The actual interface can be java.util.Set, java.util.Collection, java.util.List, java.util.Map, java.util.SortedSet, java.util.SortedMap or custom implementations of org.hibernate.usertype.UserCollectionType

Collections instances have the usual behavior of value types. They are automatically persisted when referenced by a persistent object and automatically deleted when unreferenced. If a collection is passed from one persistent object to another, its elements might be moved from one table to another. Two entities may not share a reference to the same collection instance. Due to the underlying relational model, collection-valued properties do not support null value semantics;

public class Product {

private String serialNumber;private Set parts = new HashSet();public Set getParts() { return parts; }void setParts(Set parts) { this.parts = parts; }public String getSerialNumber() { return serialNumber; }void setSerialNumber(String sn) { serialNumber = sn; }

}

Collection Mapping

<map

name="propertyName" table="table_name" schema="schema_name"lazy="true|false" inverse="true|false"cascade="all|none|save-update|delete|all-delete-orphan" sort="unsorted|natural|comparatorClass" order-by="column_name asc|desc" where="arbitrary sql where condition" fetch="join|select" batch-size="N" access="field|property|ClassName" optimistic-lock="true|false" >

<key .... /><map-key .... /><element .... />

(1)(2)(3)(4)(5)(6)(7) (8)(9)(10)(11)(12)(13)

</map>

(1) name the collection property name (2) table (optional - defaults to property name) the name of the collection table (not used for one-to-many associations) (3) schema (optional) the name of a table schema to override the schema declared on the root element (4) lazy (optional - defaults to true) enable lazy initialization (not available for arrays) (5) inverse (optional - defaults to false) mark this collection as the "inverse" end of a bidirectional association (6) cascade (optional - defaults to none) enable operations to cascade to child entities

(7) sort (optional) specify a sorted collection with natural sort order, or a given comparator class

(8)order-by (optional, JDK1.4 only) specify a table column (or columns) that define the iteration order of the Map, Set or bag, together with an optional asc or desc

(9)where (optional) specify an arbitrary SQL WHERE condition to be used when retrieving or removing the collection (useful if the collection should contain only a subset of the available data)

(10)fetch (optional, defaults to select) Choose between outer-join fetching and fetching by sequential select. Only one collection may be fetched by outer join per SQL SELECT.

(11) batch-size (optional, defaults to 1) specify a "batch size" for lazily fetching instances of this collection.

(12) access (optional - defaults to property): The strategy Hibernate should use for accessing the property value.

(13)optimistic-lock (optional - defaults to true): Species that changes to the state of the collection results in increment of the owning entity's version. (For one to many associations, it is often reasonable to disable this setting.)

These are some more mapings which we will discuss later

Association MappingComponent Mapping

HIBERNATE TUTORIAL

HIBERNATE - Hibernate Query Language

Hibernate is equipped with an extremely powerful query language that looks very much like SQL. Queries are case-insensitive, except for names of Java classes and properties.

Clause

The from clause

The simplest possible Hibernate query is of the form:

From org.applabs.base.UserFrom User

which simply returns all instances of the class org.applabs.base.User.

Most of the time, you will need to assign an alias, since you will want to refer to the User in other parts of the query.

from User as user

This query assigns the alias user to User instances, so we could use that alias later in the query. The as keyword is optional; we could also write:

from User user

Multiple classes may appear, resulting in a cartesian product or "cross" join.

from User, Groupfrom User as user, Group as group

The select clause

The select clause picks which objects and properties to return in the query result set. Queries may return properties of any value type including properties of component type:

select user.name from User userwhere user.name like 'mary%'

select customer.contact.firstName from Customer as cust

The where clause

The where clause allows you to narrow the list of instances returned.

from User as user where user.name='mary'

returns instances of User named 'mary'.

Compound path expressions make the where clause extremely powerful. Consider:

from org.applabs.base.Customer cust where cust.contact.name is not null

This query translates to an SQL query with a table (inner) join. If you were to write something like The = operator may be used to compare not only properties, but also instances:

from Document doc, User user where doc.user.name = user.name

The special property (lowercase) id may be used to reference the unique identifier of an object. (You may also use its property name.)

from Document as doc where doc.id = 131512

from Document as doc where doc.author.id = 69

The order by clause

The list returned by a query may be ordered by any property of a returned class or components:

from User user order by user.name asc, user.creationDate desc, user.email

The optional asc or desc indicate ascending or descending order respectively.

The group by clause

A query that returns aggregate values may be grouped by any property of a returned class or components:

select sum(document) from Document document group by document.category

A having clause is also allowed.

select sum(document) from Document document group by document.categoryhaving document.category in (Category.HIBERNATE, Category.STRUTS)

Associations and joins

We may also assign aliases to associated entities, or even to elements of a collection of values, using a join. The supported join types are borrowed from ANSI SQL • inner join • left outer join • right outer join • full join (not usually useful)

The inner join, left outer join and right outer join constructs may be abbreviated.

Aggregate functions

HQL queries may even return the results of aggregate functions on properties: The supported aggregate functions are

avg(...), sum(...), min(...), max(...) , count(*), count(...), count(distinct ...), count(all...) The distinct and all keywords may be used and have the same semantics as in SQL.

Expressions

Expressions allowed in the where clause include most of the kind of things you could write in SQL: • mathematical operators +, -, *, / • binary comparison operators =, >=, <=, <>, !=, like • logical operations and, or, not • string concatenation || • SQL scalar functions like upper() and lower() • Parentheses ( ) indicate grouping • in, between, is null • JDBC IN parameters ? • named parameters :name, :start_date, :x1 • SQL literals 'foo', 69, '1970-01-01 10:00:01.0' • Java public static final constants eg.Color.TABBY

Sub queries

For databases that support subselects, Hibernate supports subqueries within queries. A subquery must be surrounded by parentheses (often by an SQL aggregate function call). Even correlated subqueries (subqueries that refer to an alias in the outer query) are allowed.

HIBERNATE - Hibernate Complete Example

In this section we will extend our quick start sample into to a web based application that comprises of struts and Hibernate support.

IntroductionIn this example we will build a simple web based document repository application using hibernate. The document repository under consideration will have categorization of the documents based on the topics (Folder based like structure), Keywords for each document (this will simplify searches), versioning for each document, Document modification history, permissions based access for each entity based on users and groups.

Database scheme.The concept of properties tables: Here we have extended the concept of Hash tables to the database, Instead of adding more and more columns as per growing needs A properties table is created per Entity, Each property (Prop) table contains name and value pair that stores additional information for particular entity, thus you can store as many properties as you want for a given entity. Getter and setter methods need to be provided from the domain object so that we can represent these properties inside domain objects.

Basic entities.Basic entities such as User, Group, and Permissions along with Prop tables for each are provided to persistent data for corresponding entities, Now as a business rule a group contains multiple Users and One User can be a part of multiple Groups. Each entity, User, Group, and Permission have UserProp, GroupProp and PremissionProp respectively. The relation between Entity and Prop is one to many. E.g. User can have multiple Properties. (For simplicity, Permission tables are not shown in the model)

Categories and Documents

Category refers to a Folder/Directory like structure on the file system. Each category may or may not have its Parent Category. Category contains information like name, description, creation details, modification deleted and deletion details. Each category can have multiple entries. (Each Folder can contain one or more Documents (Entries) in it. Each Document can have one or more versions in it.(Document corresponds to version). Document contains information such as Title, Body, Summary, life cycle details, version number, keywords, workflow status, Entry details and Attachment details; Document also contains properties associated with it. Attachment is a file associated with each Document, Database stores the name of file stored on the file system and the size of Attachment.

HIBERNATE TUTORIAL


Database Scripts

--Drop TablesDROP TABLE "APP"."ATTACHMENT";DROP TABLE "APP"."CATEGORY";DROP TABLE "APP"."CATEGORY_PROP";DROP TABLE "APP"."DOCUMENT";DROP TABLE "APP"."DOCUMENT_ATTACHMENT";DROP TABLE "APP"."DOCUMENT_KEYWORDS";DROP TABLE "APP"."DOCUMENT_PROP";DROP TABLE "APP"."ENTRY";DROP TABLE "APP"."GROUP";DROP TABLE "APP"."GROUP_PROP";DROP TABLE "APP"."IDGENERATOR";DROP TABLE "APP"."KEYWORD";DROP TABLE "APP"."USER";DROP TABLE "APP"."USER_GROUP";DROP TABLE "APP"."USER_PROP";

-- Table: "APP"."ATTACHMENT"CREATE TABLE "APP"."ATTACHMENT"("ATTACHMENT_ID" numeric NOT NULL,"DOCUMENT_ID" numeric,"ATTACHMEMT_PATH" varchar,"ATTACHMENT_SIZE" numeric,CONSTRAINT "ATTACHMENT_pkey" PRIMARY KEY ("ATTACHMENT_ID"));

-- Table: "APP"."CATEGORY"CREATE TABLE "APP"."CATEGORY"(

"CATAGORY_ID" numeric NOT NULL,"CATEGORY_NAME" varchar,"CATEGORY_DESCRIPTION" varchar,"CREATED_BY" numeric,"CREATION_DATE" date,"MODIFIED_BY" numeric,"MODIFICATION_DATE" date,"DELETED_BY" numeric,"DELETE_DATE" date,"PARENT_CATAGORY" numeric,CONSTRAINT "CATEGORY_pkey" PRIMARY KEY ("CATAGORY_ID"),CONSTRAINT "CATEGORY_PARENT_CATAGORY_fkey" FOREIGN KEY ("PARENT_CATAGORY") REFERENCES "APP"."CATEGORY" ("CATAGORY_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT authorfk FOREIGN KEY ("CREATED_BY") REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT deletorfk FOREIGN KEY ("DELETED_BY") REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT editorfk FOREIGN KEY ("MODIFIED_BY") REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."CATEGORY_PROP"CREATE TABLE "APP"."CATEGORY_PROP"("CATEGORY_PROP_ID" numeric NOT NULL,"CATEGORY_ID" numeric,"PROP_NAME" varchar,"PROP_VALUE" varchar,CONSTRAINT "CATEGORY_PROP_pkey" PRIMARY KEY ("CATEGORY_PROP_ID"),CONSTRAINT "CATEGORY_PROP_CATEGORY_ID_fkey" FOREIGN KEY ("CATEGORY_ID") REFERENCES "APP"."CATEGORY" ("CATAGORY_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."DOCUMENT"CREATE TABLE "APP"."DOCUMENT"("DOCUMENT_ID" numeric NOT NULL,"DOCUMENT_TITLE" varchar,"DOCUMENT_BODY" varchar,"DOCUMENT_SUMMARY" varchar,"CREATED_BY" numeric,"CREATION_DATE" date,"MODIFIED_BY" numeric,"MODIFICATION_DATE" date,"DELETED_BY" numeric,"DELETED_DATE" date,"DOCUMENT_VERSION" numeric,"DOCUMENT_STATUS" numeric,

"ENTRY_ID" numeric,CONSTRAINT "DOCUMENT_pkey" PRIMARY KEY ("DOCUMENT_ID"),CONSTRAINT "DOCUMENT_ENTRY_ID_fkey" FOREIGN KEY ("ENTRY_ID") REFERENCES "APP"."ENTRY" ("ENTRY_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT authorfk FOREIGN KEY ("CREATED_BY") REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT deletorfk FOREIGN KEY ("DELETED_BY") REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT editorfk FOREIGN KEY ("MODIFIED_BY") REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."DOCUMENT_ATTACHMENT"CREATE TABLE "APP"."DOCUMENT_ATTACHMENT"("DOCUMENT_ATTACHMENT_ID" numeric NOT NULL,"ATTACHMENT_ID" numeric,"DOCUMENT_ID" numeric,"ATTACHMENT_PATH" varchar,"ATTACHMENT_SIZE" numeric,CONSTRAINT "DOCUMENT_ATTACHMENT_pkey" PRIMARY KEY ("DOCUMENT_ATTACHMENT_ID"),CONSTRAINT "DOCUMENT_ATTACHMENT_ATTACHMENT_ID_fkey" FOREIGN KEY ("ATTACHMENT_ID") REFERENCES "APP"."ATTACHMENT" ("ATTACHMENT_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT "DOCUMENT_ATTACHMENT_DOCUMENT_ID_fkey" FOREIGN KEY ("DOCUMENT_ID") REFERENCES "APP"."DOCUMENT" ("DOCUMENT_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."DOCUMENT_KEYWORDS"CREATE TABLE "APP"."DOCUMENT_KEYWORDS"("DOCUMENT_KEYWORD_ID" numeric NOT NULL,"DOCUMENT_ID" numeric,"KEYWORD_ID" numeric,z CONSTRAINT "DOCUMENT_KEYWORDS_pkey" PRIMARY KEY ("DOCUMENT_KEYWORD_ID"),CONSTRAINT "DOCUMENT_KEYWORDS_DOCUMENT_ID_fkey" FOREIGN KEY ("DOCUMENT_ID") REFERENCES "APP"."DOCUMENT" ("DOCUMENT_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT keywordidfk FOREIGN KEY ("KEYWORD_ID") REFERENCES "APP"."KEYWORD" ("KEYWORD_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."DOCUMENT_PROP"CREATE TABLE "APP"."DOCUMENT_PROP"(document_prop_id numeric NOT NULL,document_id numeric NOT NULL,prop_name varchar NOT NULL,prop_value varchar,prop_value_details varchar,

CONSTRAINT "DOCUMENT_PROP_pkey" PRIMARY KEY (document_prop_id),CONSTRAINT "DOCUMENT_PROP_document_id_fkey" FOREIGN KEY (document_id) REFERENCES "APP"."DOCUMENT" ("DOCUMENT_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."ENTRY"CREATE TABLE "APP"."ENTRY"("ENTRY_ID" numeric NOT NULL,"CATEGORY_ID" numeric,CONSTRAINT "ENTRY_pkey" PRIMARY KEY ("ENTRY_ID"),CONSTRAINT "ENTRY_CATEGORY_ID_fkey" FOREIGN KEY ("CATEGORY_ID") REFERENCES "APP"."CATEGORY" ("CATAGORY_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."GROUP"CREATE TABLE "APP"."GROUP"("GROUP_ID" numeric NOT NULL,"GROUP_NAME" varchar,"GROUP_DESCRIPTION" varchar,"CREATED_BY" numeric,"CREATION_DATE" date,"MODIFIED_BY" numeric,"MODIFICATION_DATE" date,"DELETED_BY" numeric,"DELETE_DATE" date,CONSTRAINT "GROUP_ID_pk" PRIMARY KEY ("GROUP_ID") USING INDEX TABLESPACE apptablespace);

-- Table: "APP"."GROUP_PROP"CREATE TABLE "APP"."GROUP_PROP"(group_prop_id numeric NOT NULL,group_id numeric NOT NULL,prop_name varchar NOT NULL,prop_value varchar,prop_value_details varchar,CONSTRAINT "GROUP_PROP_pkey" PRIMARY KEY (group_prop_id),CONSTRAINT "GROUP_PROP_group_id_fkey" FOREIGN KEY (group_id) REFERENCES "APP"."GROUP" ("GROUP_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);-- Table: "APP"."IDGENERATOR"CREATE TABLE "APP"."IDGENERATOR"(id numeric NOT NULL,next_value numeric NOT NULL,CONSTRAINT "IDGENERATOR_pkey" PRIMARY KEY (id)

);

-- Table: "APP"."KEYWORD"CREATE TABLE "APP"."KEYWORD"("KEYWORD_ID" numeric NOT NULL,"KEYWORD_NAME" varchar,"KEYWORD_DESCRIPTION" varchar,CONSTRAINT "KEYWORD_pkey" PRIMARY KEY ("KEYWORD_ID"));

-- Table: "APP"."USER"CREATE TABLE "APP"."USER"("USER_ID" numeric NOT NULL,"USER_NAME" varchar,"USER_PASSWORD" varchar,"USER_FIRST_NAME" varchar,"USER_LAST_NAME" varchar,"CREATION_DATE" date,"CREATED_BY" numeric,"MODIFICATION_DATE" date,"MODIFIED_BY" numeric,"DELETE_DATE" date,"DELETED_BY" numeric,CONSTRAINT "USER_pkey" PRIMARY KEY ("USER_ID"));

-- Table: "APP"."USER_GROUP"CREATE TABLE "APP"."USER_GROUP"("USER_GROUP" numeric NOT NULL,"USER_ID" numeric,"GROUP_ID" numeric,CONSTRAINT "USER_GROUP_pkey" PRIMARY KEY ("USER_GROUP"),CONSTRAINT "USER_GROUP_GROUP_ID_fkey" FOREIGN KEY ("GROUP_ID") REFERENCES "APP"."GROUP" ("GROUP_ID") ON UPDATE NO ACTION ON DELETE NO ACTION,CONSTRAINT "USER_GROUP_USER_ID_fkey" FOREIGN KEY ("USER_ID") REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);

-- Table: "APP"."USER_PROP"CREATE TABLE "APP"."USER_PROP"

(user_prop_id numeric NOT NULL,user_id numeric NOT NULL,prop_name varchar NOT NULL,prop_value varchar,prop_value_details varchar,CONSTRAINT "USER_PROP_pkey" PRIMARY KEY (user_prop_id),CONSTRAINT "USER_PROP_user_id_fkey" FOREIGN KEY (user_id) REFERENCES "APP"."USER" ("USER_ID") ON UPDATE NO ACTION ON DELETE NO ACTION);


Database Tables Overview

Click to Download Table Overview

http://www.allapplabs.com/images/hibernate_table_overview.zip


hbm files

User.hbm.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN"

"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping> <class name="org.applabs.base.User" table="USER">

<id column="USER_ID" name="id" type="java.lang.Long">

<generator class="org.hibernate.id.TableHiLoGenerator">

<param name="table">idgen</param><param name="column">NEXT</param>

</generator>

</id>

<property column="USER_NAME" name="userName" type="java.lang.String"/><property column="USER_PASSWORD" name="userPassword" type="java.lang.String"/><property column="USER_FIRST_NAME" name="userFirstName" type="java.lang.String"/><property column="USER_EMAIL" name="userEmail" type="java.lang.String"/><property column="USER_LAST_NAME" name="userLastName" type="java.lang.String"/><property column="CREATION_DATE" length="4" name="creationDate" type="java.util.Date"/><property column="CREATED_BY" name="createdBy" type="java.lang.Double"/><property column="MODIFICATION_DATE" length="4" name="modificationDate" type="java.util.Date"/><property column="MODIFIED_BY" name="modifiedBy" type="java.lang.Double"/><property column="DELETE_DATE" length="4" name="deleteDate" type="java.util.Date"/><property column="DELETED_BY" name="deletedBy" type="java.lang.Double"/><set name="properties" lazy="true" inverse="true" cascade="all-delete-orphan">

<key column="USER_ID" /><one-to-many class="org.applabs.base.UserProp" />

</set>

</class></hibernate-mapping>

UserProp.hbm.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping> <class name="org.applabs.base.UserProp" table="USER_PROP"> <id column="USER_PROP_ID" name="id" type="java.lang.Long"> <generator class="org.hibernate.id.TableHiLoGenerator">


</generator> </id> <property column="CATEGORY_NAME" name="categoryName" type="java.lang.String"/>

<property column="CATEGORY_DESCRIPTION" name="categoryDescription" type="java.lang.String"/><property column="CREATED_BY" name="createdBy" type="java.lang.Double"/><property column="CREATION_DATE" length="4" name="creationDate" type="java.util.Date"/><property column="MODIFIED_BY" name="modifiedBy" type="java.lang.Double"/><property column="MODIFICATION_DATE" length="4" name="modificationDate" type="java.util.Date"/>

<property column="DELETED_BY" name="deletedBy" type="java.lang.Double"/><property column="DELETE_DATE" length="4" name="deleteDate" type="java.util.Date"/><!—- One way of implementing --><!—- Another way of One-to-many Mapping --><set name="childCatagories">

<key column="CATAGORY_ID" not-null="true"/><one-to-many class="org.applabs.base.Category"/>

</set> <set name="properties" lazy="true" inverse="true" cascade="all-delete-orphan">

<key column="CATEGORY_ID" /><one-to-many class="org.applabs.base.CategoryProp" />

</set> </class></hibernate-mapping>

Category.hbm.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping> <class name="org.applabs.base.Category" table="CATEGORY"> <id column="CATAGORY_ID" name="id" type="java.lang.Long"> <generator class="org.hibernate.id.TableHiLoGenerator">


</generator> </id>

<property column="CATEGORY_NAME" name="categoryName" type="java.lang.String"/><property column="CATEGORY_DESCRIPTION" name="categoryDescription" type="java.lang.String"/><property column="CREATED_BY" name="createdBy" type="java.lang.Double"/><property column="CREATION_DATE" length="4" name="creationDate" type="java.util.Date"/><property column="MODIFIED_BY" name="modifiedBy" type="java.lang.Double"/><property column="MODIFICATION_DATE" length="4" name="modificationDate" type="java.util.Date"/><property column="DELETED_BY" name="deletedBy" type="java.lang.Double"/><property column="DELETE_DATE" length="4" name="deleteDate" type="java.util.Date"/><!—- One way of implementing --><!—- Another way of One-to-many Mapping --><set name="childCatagories">

<key column="CATAGORY_ID" not-null="true"/><one-to-many class="org.applabs.base.Category"/>

</set> <set name="properties" lazy="true" inverse="true" cascade="all-delete-orphan">

<key column="CATEGORY_ID" /><one-to-many class="org.applabs.base.CategoryProp" />


CategoryProp.hbm.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping> <class name="org.applabs.base.CategoryProp" table="CATEGORY_PROP"> <id column="CATEGORY_PROP_ID" name="id" type="java.lang.Long"> <generator class="org.hibernate.id.TableHiLoGenerator">


</generator> </id>

<property column="CATEGORY_ID" name="categoryId" type="java.lang.Long"/><property column="PROP_NAME" name="propName" type="java.lang.String"/><property column="PROP_VALUE" name="propValue" type="java.lang.String"/>


Document.hbm.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping> <class name="org.applabs.base.Document" table="DOCUMENT"> <id column="DOCUMENT_ID" name="id" type="java.lang.Long"> <generator class="sequence"/> </id> <property column="DOCUMENT_TITLE" name="documentTitle" type="java.lang.String"/>

<property column="DOCUMENT_BODY" name="documentBody" type="java.lang.String"/><property column="DOCUMENT_SUMMARY" name="documentSummary" type="java.lang.String"/><property column="CREATED_BY" length="65535" name="createdBy" type="java.lang.Double"/><property column="CREATION_DATE" length="4" name="creationDate" type="java.util.Date"/><property column="MODIFIED_BY" length="65535" name="modifiedBy" type="java.lang.Double"/><property column="MODIFICATION_DATE" length="4" name="modificationDate" type="java.util.Date"/><property column="DELETED_BY" length="65535" name="deletedBy" type="java.lang.Double"/><property column="DELETED_DATE" length="4" name="deletedDate" type="java.util.Date"/><property column="DOCUMENT_VERSION" length="65535" name="documentVersion" type="java.lang.Double"/>

<property column="DOCUMENT_STATUS" length="65535" name="documentStatus" type="java.lang.Double"/><property column="ENTRY_ID" length="65535" name="entryId" type="java.lang.Double"/>


DocumentProp.hbm.xml

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE hibernate-mapping PUBLIC"-//Hibernate/Hibernate Mapping DTD 3.0//EN""http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"><hibernate-mapping> <class name="org.applabs.base.DocumentProp" table="DOCUMENT_PROP"> <id column="document_prop_id" name="id" type="java.lang.Long"> <generator class="sequence"/> </id>

<property column="document_id" length="65535" name="documentId" not-null="true" type="java.lang.Double"/><property column="prop_name" name="propName" not-null="true" type="java.lang.String"/><property column="prop_value" name="propValue" type="java.lang.String"/><property column="prop_value_details" name="propValueDetails" type="java.lang.String"/>


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