ObjectDB Database Search

|| NOT ! JPQL follows the SQL notation, while Java uses its own notation (which is also in use by JDOQL ... expressions are represented in criteria queries by Expression and descendant interfaces. For example, a boolean path (a field or a property) is represented by Path : Path isInUN = country

The following arithmetic operators are supported by JPA: 2 unary operators:   + (plus) and - (minus). 4 ... of the same type. The MOD Function The MOD function calculates the remainder of the division of one number by another, similar to the modulo operator ( % ) in Java (which is also supported by ObjectDB as

named queries instead of dynamic queries may improve code organization by separating the JPQL ... carefully to avoid collision (e.g. by using the unique entity name as a prefix). It makes sense to add ... at Runtime Named queries are represented at runtime by the same Query and TypedQuery interfaces

Queries are represented in JPA 2 by two interfaces - the old Query interface ... with an EntityManager (represented by em in the following code snippets), which serves as a factory ... which retrieves all the Country objects in the database is represented by both q1 and q2 . When building

: This page explains how ObjectDB configuration works in general. The Configuration Path By default ... explicitly by setting the "objectdb.home" system property: System.setProperty("objectdb.home", "/odb ... : $ java "-Dobjectdb.home=/odb" ... The Configuration File As noted above, by default

by fields that are marked with CascadeType . PERSIST or CascadeType . ALL are also persisted ... yet are also persisted. Automatic Change Tracking As shown above, an update is achieved by modifying a managed ... demonstrated above, array changes are not detected automatically ( by default) but it is possible

This chapter demonstrates basic ObjectDB and JPA concepts by introducing a simple example program ... that contains points in the plane. Each point is represented by an object with two int fields, x and y, that hold the point's x and y coordinates. The program demonstrates CRUD database operations by

., column alias, if applicable. Scalar result types can be included in the query result by specifying ... order _id, " + "o.quantity AS order _quantity, " + "o.item AS order _item, " + "i.name AS item_name, " + "FROM Order o, Item i " + "WHERE ( order _quantity 25) AND ( order _item = i.id)", "OrderResults

are scoped to the persistence unit. A named query may be executed by calling (String, Class) . In simple ... " + "FROM Order o, Item i " + "WHERE (o.item = i.id) AND (i.name = 'widget')", resultClass = com.acme. Order .class )} In more complicated cases, a plain is needed

are specified by the parameters element. Parameters must be specified in the order in which they occur in ... must be the same as the order in which the result sets are returned by the stored procedure invocation ... , as defined by the SqlResultSetMapping annotation. If there are multiple result sets, it is assumed

, other schema changes are handled by ObjectDB automatically. Note: Extreme caution is required ... is changed from the original name, which is specified by the required name attribute, to the new name ... attribute is specified the class name is changed from the original name, which is specified by

of the Java Data Objects (JDO) API than competing object databases. By using a standard API such as JPA ... relational database by using an ORM JPA provider such as Hibernate, EclipseLink or Open JPA ... . The support of two standard APIs (JPA and JDO) by ObjectDB minimizes the risk

number generator is also used to generate numeric values for primary key fields annotated by ... is 50). A sequence is global to the application and can be used by one or more fields in one or ... server, IDs are allocated in groups. The number of IDs in each allocation is specified by

of an entity class are detected by ObjectDB. New entity objects have to be stored in the new class ... again. Conversion of an entity object to the new schema is done on a field by field basis: For every field ... ) The automatic schema evolution mechanism, as described above, is based on matching fields by

This chapter introduced the basic principles of JPA using ObjectDB. You can go into details by ... your own ObjectDB/JPA projects simply by modifying this sample program. Reading the Next Chapters ... the picture by describing some tools and settings that are specific to ObjectDB:

collection after query execution (e.g. by results.get(0) ). To eliminate this routine operation JPA ... = (Long)query. getSingleResult (); An aggregate COUNT query always returns one result, by definition ... - the executeUpdate method returns the number of objects that have been updated or deleted by the query

. The four relationship modes are represented by the following annotations: Unlike ORM JPA ... annotations are supported by ObjectDB for the inverse side of a bidirectional relationship (which is calculated by a query) : Details about all these annotations are provided in Chapter 2 of the ObjectDB manual.

;      Every user is represented by a single element: The required username ... inherited by all the other user definitions but the master user itself cannot be used to connect ... . $user represents the user's username and if specified for the master ( "$default") it is interpreted by

: AbstractQuery Since: JPA 2.0 List getOrderList () Return the ordering expressions in order of precedence. Returns empty list if no ordering expressions have been specified. Modifications to the list do not affect the query. Return: the list of ordering expressions Since: JPA 2.0 Class getResultType

: If the type of the criteria query is CriteriaQuery (i.e., a criteria query object created by either the createTupleQuery method or by passing a Tuple class argument to the createQuery method), a Tuple object corresponding to the elements of the list passed to the multiselect method, in the specified order

In this final step we will add a simple table to the report: Open the [Insert Table] dialog box by ... ) layout. Set the column number to 2 , number of details to 1 , select the data set (e.g. Points by X ) in the third field and click OK . Fill the table with data by dragging the x and y columns from

We start by creating a new Eclipse Dynamic Web Project: Open the [New Project] dialog box, e.g. by ... as a new server by clicking the New Runtime... button . Follow the instructions and specify the path ... web project. Now, add ObjectDB support to the new Eclipse Project - by dragging the objectdb

The Guest entity objects will be stored in an ObjectDB database, which will be represented by ... created if not existing yet) when the web application starts, by instantiating ... down), by closing the  EntityManagerFactory . To register a ServletContextListener : Open the [New

] dialog box by right clicking the WEB-INF node under the Web Pages node (in the [Projects] window ... , which contains a simple form for signing the guestbook, followed by a list of all the guests that have already signed (which are retrieved from the request's guestDao attribute that is set by

the [New Java Class] dialog box, e.g. by right clicking the project node (in the [Package Explorer] window ... + ")"; } } The Guest entity class will represents guests in the database. We also need to configure JPA by setting a META-INF/persistence.xml file: Open the [New Folder] dialog box, e.g. by right clicking the project

a basic guestbook page. Every visitor can sign the guestbook by filling a simple form. The visitors that have already signed are listed below the form: Persistence is managed by JPA. Every visitor that has signed the guestbook is represented by a  Guest JPA entity object and all the  Guest

You can run the application now by right clicking the Main node (in the [Projects] window ... 1,000 objects. You can view the content of the database file by opening it in the ObjectDB Explorer : This is the end of the tutorial. Learn more about ObjectDB and JPA by reading the Manual .

The  JPA Web Application tutorial provides step by step instructions on how to build a simple ... . Building a new application step by step is an effective way to learn - but if you prefer ... ) If  Maven is installed - extract the zip and run the application from the command line by

We start by creating a new Maven-WTP dynamic web project in Eclipse: Open the [New Project] dialog box, e.g. by using  File New Project... Select  Maven Maven Project and click  ... folder: Note: You should verify now that Maven Integration for WTP is installed, by right clicking

application manages a basic guestbook page. Every visitor can sign the guestbook by filling a simple form. The visitors that have already signed are listed below the form: Persistence is managed by JPA. Every visitor that has signed the guestbook is represented by a Guest entity object

We start by creating a new Java EE dynamic web project in Eclipse: Open the [New Project] dialog box, e.g. by using File New Project... Select Web Dynamic Web Project and click Next . Choose ... runtime. Note: You may have to add GlassFish 3 as a new server by clicking the New Runtime... button

the [New Entity Class] dialog box, e.g. by right clicking the project node (in the [Projects] window ... to the project (under Configuration Files). Open the persistence.xml file in a text editor ( by right clicking and selecting Edit or by double click and then moving to the Source or XML tab in

can sign the guestbook by filling a simple form. The visitors that have already signed are listed below the form: Persistence is managed by JPA. Every visitor that has signed the guestbook is represented by a  Guest entity object and all the  Guest entity objects are stored in an ObjectDB

] dialog box by right clicking the Web Pages node (in the [Projects] window) and selecting New JSP ... a simple form for signing the guestbook, followed by a list of all the guests that have already signed (which are retrieved from the request's "guests" attribute that is set by the servlet in

You can now run the application by right clicking the Main.java file (in the [ Package Explorer ] window) and selecting Run As Java Application . The expected output in the Eclipse [Console] window ... by opening it in the ObjectDB Explorer : This is the end of the Eclipse JPA tutorial. Learn more about ObjectDB and JPA by reading the Manual .

manages a basic guestbook page. Every visitor can sign the guestbook by filling a simple form. The visitors that have already signed are listed below the form: Persistence is managed by JPA. Every visitor that has signed the guestbook is represented by a Guest JPA entity object and all the Guest

can sign the guestbook by filling a simple form. The visitors that have already signed are listed below the form: Persistence is managed by JPA. Every visitor that has signed the guestbook is represented by a Guest entity object and all the Guest entity objects are stored in an ObjectDB database

. The demo web application manages a basic guestbook page. Every visitor can sign the guestbook by ... is managed by JPA. Every visitor that has signed the guestbook is represented by a Guest entity object

The Getting Started with JPA tutorial provides step by step instructions on how to build a simple JPA database driven application in Eclipse or NetBeans . Building a new application step by step ... ) If Maven is installed - extract the zip and run the application from the command line by : mvn test

can sign the guestbook by filling a simple form. The visitors that have already signed are listed below the form: Persistence is managed by JPA. Every visitor that has signed the guestbook is represented by a  Guest entity object and all the  Guest entity objects are stored in an ObjectDB

To store objects in an ObjectDB database using JPA we need to define an entity class: Open the [New Entity Class] dialog box, e.g. by right clicking the project node (in the [Projects] window ... a text editor ( by right clicking and selecting Edit or by double click and then moving to the XML

. Every visitor can sign the guestbook by filling a simple form. The visitors that have already signed are listed below the form: Persistence is managed by JPA. Every visitor that has signed the guestbook is represented by a Guest entity object and all the Guest entity objects are stored in

] dialog box by right clicking the Web Pages node (in the [Projects] window) and selecting New JSP ... a simple form for signing the guestbook, followed by a list of all the guests that have already signed (which are retrieved from the request's "guests" attribute that is set by the servlet in

] dialog box by right clicking the WebContent node (in the [Package Explorer] window), selecting ... the guestbook, followed by a list of all the guests that have already signed (which are retrieved from the request's "guests" attribute that is set by the servlet in the previous step). The next step

] dialog box by right clicking WEB-INF under src/main/webapp (in the [Package Explorer] window ... the guestbook, followed by a list of all the guests that have already signed (which are retrieved from the request's  guestDao attribute that is set by the controller in the previous step

box by right clicking the guest package node (in the [Projects] window) and selecting New Servlet ... to generate the page output. Notice that operations on the database are carried on by the  GuestDao session bean, which is instantiated and injected by the application server into the 

] dialog box by right clicking the WebContent node (in the [Package Explorer] window), selecting ... generates the guestbook page output, which contains a simple form for signing the guestbook, followed by ... " attribute that is set by the servlet in the previous step). The next step (and the last one in this tutorial) is running the web application .

In this step we will add a servlet to manage guestbook web requests: Open the [Create Servlet] dialog box by right clicking the guest package node (in the [Package Explorer] window), selecting  ... on the database are carried on by the GuestDao session bean, which is instantiated and injected by

the [New Data Set] dialog box by right clicking the Data Sets node in the [Data Explorer] window ... Points ).  Enter a data set name (e.g. Points by X ) and click Next . The database in ... ) and high ( 20 ): You may click Preview Results  to see the query results: Close the dialog box by

We start by creating a new NetBeans Web Application Project: Open the [New Project] dialog box, e.g. by using File New Project... Select Java Web Web Application and click Next . Choose a Project ... : You may have to add Tomcat 6 as a new server by clicking the Add... button . Follow the instructions and specify