ObjectDB Database Search

and sometimes we don't get the entity by query. Have you an idea what happens here?   btc_es BTC EmbeddedSystems

("query", "%myQuery%"); I don't get any error! The order of the WHERE clauses obviously makes

Metamodel API is Metamodel . It can be obtained either by the EntityManagerFactory 's getMetamodel method or by the EntityManager 's getMetamodel method (both methods are equivalent). For example, given an EntityManager , em , a Metamodel instance can be obtained by : Metamodel metamodel = em

variables are represented in criteria queries by descendant interfaces of the From interface: Range variables (bound by an entity class) are represented by the Root subinterface: Join variables (bound by an attribute of a preceding variable in the FROM clause) are represented by the Join subinterface

language. For step by step instructions on using BIRT with ObjectDB see the  Report Generation ... Developers extension. To install it: Open the [Install] dialog box by selecting Help Install New Software ... and press ENTER. Select the ObjectDB Birt/ODA feature. Complete the installation by clicking Next twice

;x) Create an ordering by the ascending value of the expression. Parameters: x - expression used ... : expression for current timestamp Since: JPA 2.0 Order desc ( Expression  x) Create an ordering by ... , predicates, orderings . Note that Predicate is used instead of Expression in this API in order

for ordering that is visible as persistent state and maintained by the application. The OrderBy annotation ... a column that is used to maintain the persistent order of a list. The persistence provider is responsible for maintaining the order upon retrieval and in the database. The persistence provider

are handled. ObjectDB can manage non enhanced classes by using reflection at the cost of performance ... entities are always held by strong references in the persistence context (until commit or flush ... that is managed by the EntityManagerFactory and shared by all its EntityManager instances. The level 2 cache

a limit size that is specified by the threshold attribute. The mb and kb suffixes represent megabytes ... has to be specified for ObjectDB to avoid using sockets that are expired by the firewall. The element    ObjectDB manages a list of the recently accessed database URLs for use by the Explorer

An ObjectDB database can be backed up by simply copying or archiving the database file while the database is offline (i.e. when it is not open in an ObjectDB server and not in use by any application ... . Starting Online Backup The online backup can be started by executing a special query on an EntityManager

alias, if applicable. Scalar result types can be included in the query result by specifying this annotation in the metadata. Example: Query q = em.createNativeQuery( "SELECT o.id AS order _id, " + "o.quantity AS order _quantity, " + "o.item AS order _item, " + "i.name AS item_name, " + "FROM Order o, Item

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

is affected also by other elements in the configuration file, particularly the and the configuration elements ... . If another port is specified it also has to be specified by clients in the URL connection string ... specifies the maximum number of simultaneous connections that are accepted by the server. A request

: 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

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

|| 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

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

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

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

to the order of the where clouse and the 2.7.4 wasn't. Unfortunatly I was not able to strip ... to the order of the where clause, meaning that the result set differs. As far as I understand there might be some performence issues related to the order but no different result set

must be specified in the order in which the result sets will be returned by the stored procedure ... in the order in which the result sets will be returned by the stored procedure invocation ... to create and remove persistent entity instances, to find entities by their primary key

As demonstrated in this forum thread , a mapped by collection field with lazy fetch mode is not initialized in results of a query that uses JOIN FETCH on that collection field (when enhancement is used). support Support   Build 2.4.1_06 fixes this issue (fields are now initialized

;      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

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

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

. 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.

, 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

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

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:

We start by installing the BIRT development environment and the ObjectDB data source driver ... IDE for Java EE Developers. Update your existing Eclipse IDE for Java EE Developers environment by ... an existing  Eclipse IDE for Java EE Developers environment: Open the [Install] dialog box by

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

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 an EntityManagerFactory . The database will be closed when the web application stops (or when the web server shuts down), by

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

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 .

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 .

] 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

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

] 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 .

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

. 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

] 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

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 

. 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

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

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

] 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

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

classes and to perform common operations needed by implementations, not by end users. JDOImplHelper ... restriction on this access. JDO implementations get access to the functions provided by this class only if they are authorized by the security manager. To avoid having every call go through the security

This class can be used by a JDO-aware application to call the JDO behavior of PersistenceCapable ... of PersistenceCapable classes have a JDO identity managed by the PersistenceManager . This method returns ... instance with the same data store identity. If the JDO identity is managed by the application