ObjectDB Database Search

identified in a query string by their special form, which is a colon (:) followed by a valid JPQL ... appearing in the query string. The parameter type is inferred by the context. In the above example ... . Queries can include multiple parameters, and each parameter can occur multiple times in the query

Literals in JPQL, as in Java, represent constant values. JPQL supports various types of literals ... parameter values. Literals should only be embedded in JPQL queries when a single constant value ... to null in Java and SQL. Since JPQL is case insensitive, NULL , null and Null are equivalent. Notice

in ObjectDB (and in JPA) is always at the database object level, i.e. each database object ... to pessimistic locking it is easier to use and more efficient. In the rare cases in which update collision ... object. The initial version of a new entity object (when it is stored in the database for the first

Collections may appear in JPQL queries: as parameters - when collections are assigned as arguments. as  path expressions - in navigation to persistent collection fields. IS [NOT] EMPTY ... of elements in a specified collection. For example: SIZE(c.languages)  is evaluated

classes) are represented in JPQL by the following types of expressions: Variables - FROM ... defined persistable classes can participate in direct comparison using the = and operators. But more often they are used in JPQL path expressions that navigate to values of simple types (number, boolean

String values may appear in JPQL queries in various forms: as  string literals - e.g. 'abc' , ''. as parameters - when string values are assigned as arguments. as  path expressions - in ... ;is evaluated to TRUE . '100' LIKE '%\%' ESCAPE '\' is evaluated to FALSE . In the expressions

Most JPQL queries use at least one comparison operator in their WHERE clause. Comparison Operators ObjectDB supports two sets of comparison operators, as shown in the following table:   Set 1 ... != The two sets differ in the Equal and the Not Equal operators. JPQL follows the SQL notation, where Java uses

Logical operators in JPQL and in JPA criteria queries enable composition of complex JPQL boolean ... of logical operators, as shown in the following table: Set 1 - JPQL / SQL Set 2 - Java / JDO AND && OR || NOT ! JPQL follows the SQL notation, while Java uses its own notation (which is also in use by JDOQL

Numeric values may appear in JPQL queries in many forms: as  numeric literals - e.g. 123 , -12.5 . as parameters - when numeric values are assigned as arguments. as  path expressions - in ... also supports the % (modulo) and the ~ (bitwise complement) operators that are supported in Java

Existing entity objects can be updated, as explained  in chapter 2 , by: Retrieving ... , but when executed, update the content of specified entity objects in the database. Updating entity objects in ... that a cached entity object in its persistence context has been modified by an UPDATE query

Date and time expressions may appear in JPQL queries: as date and time literals - e.g. {d '2011-12 ...   path expressions - in navigation to persistent date and time fields. as results of predefined ... to 0 . Date and Time in Criteria Queries The CriteriaBuilder interface provides three factory methods

As explained  in chapter 2 , entity objects can be deleted from the database by ... that a cached entity object in its persistence context has been removed from the database by ... variable ObjectDB supports using the java.lang.Object  class in queries (as an extension to JPA

JPA Interface In Super Interfaces: Expression , Predicate , Selection , TupleElement Interface used to build in predicates. Since: JPA 2.0 Public Methods Expression getExpression () Return ... .0 CriteriaBuilder. In value ( Expression  value) Add to list of values to be tested

JPA Method in jakarta.persistence.criteria.CriteriaBuilder CriteriaBuilder. In in (    Expression  expression ) Create predicate to test whether given expression is contained in a list of values. Parameters: expression - to be tested against list of values Return: in predicate Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$ In CriteriaBuilder. In value (    Expression  value ) Add to list of values to be tested against. Parameters: value - expression Return: in predicate Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$ In CriteriaBuilder. In value (   T value ) Add to list of values to be tested against. Parameters: value - value Return: in predicate Since: JPA 2.0

JPA Method in javax.persistence.criteria.CriteriaBuilder$ In Expression getExpression () Return the expression to be tested against the list of values. Return: expression Since: JPA 2.0

JPA Enum Constant in jakarta.persistence.ParameterMode IN Stored procedure input parameter Since: JPA 2.1

JPA Method in jakarta.persistence.criteria.Expression Predicate in (   Collection  values ) Create a predicate to test whether the expression is a member of the collection. Parameters: values - collection of values to be tested against Return: predicate testing for membership Since: JPA 2.0

JPA Method in jakarta.persistence.criteria.Expression Predicate in (    Expression  values ) Create a predicate to test whether the expression is a member of the collection. Parameters: values - expression corresponding to collection to be tested against Return: predicate testing for membership Since: JPA 2.0

JPA Method in jakarta.persistence.criteria.Expression Predicate in (    Expression ... values ) Create a predicate to test whether the expression is a member of the argument list. Parameters: values - expressions to be tested against Return: predicate testing for membership Since: JPA 2.0

JPA Method in jakarta.persistence.criteria.Expression Predicate in (   Object... values ) Create a predicate to test whether the expression is a member of the argument list. Parameters: values - values to be tested against Return: predicate testing for membership Since: JPA 2.0

to view data in ObjectDB databases, execute JPQL and JDOQL queries and edit the content of databases. Running the Explorer The ObjectDB Explorer is contained in the explorer.jar executable jar file, which is located in the bin directory of ObjectDB. It depends on the objectdb.jar file. You can run

, persistent and inverse fields) can be used in both entity classes and embeddable classes . However, the last two groups (primary key and version fields) can only be used in entity classes. Primary key fields are discussed in the Primary Key section. Transient Fields Transient entity fields are fields

OF THIS AGREEMENT. 1. DEFINITIONS "Contribution" means: a) in the case of the initial Contributor, the initial code and documentation distributed under this Agreement, and b) in the case of each subsequent ... which: (i) are separate modules of software distributed in conjunction with the Program

The term persistable types refers to data types that can be used for storing data in the database ... can be stored in the database directly. Other persistable types can be embedded in entity classes as fields . In addition, only instances of entity classes preserve identity and are stored

clause in the query execution order is after the FROM and WHERE clauses, but before the SELECT clause. When a GROUP BY clause exists in a JPQL query, database objects (or tuples of database objects ... over all the Country objects in the database. The GROUP BY clause groups these Country objects by

New entity objects can be stored in the database either explicitly by invoking the persist method ... an instance of the Employee entity class in the database: Employee employee = new Employee("Samuel ... its state to Managed. The new entity object is stored in the database when the transaction

The FROM clause declares query identification variables that represent iteration over objects in the database. A query identification variable is similar to a variable of a Java enhanced for loop in ... at the WHERE clause level by using a type expression . For example, in the following query, c iterates

Querying without indexes requires iteration over entity objects in the database one by ... . Index management introduces overhead in terms of maintenance time and storage space, so deciding ... that prevents duplicate values in the indexed field. A PersistenceException is thrown on commit (or flush

entity object is not found in the persistence context a new object is constructed and filled ... . Therefore, it is recommended to avoid unnecessary time consuming operations in no-arg constructors ... object in its persistence context no retrieval is required and the existing managed object

the Service. By using the Service, You agree to the collection and use of information in accordance ... shall have the same meaning regardless of whether they appear in singular or in plural. Definitions ... ", "We", "Us" or "Our" in this Agreement) refers to ObjectDB Software Ltd, 109 Vernon House Friar Lane Unit 632

mean the work of authorship, whether in Source or Object form, made available under the License, as indicated by a copyright notice that is included in or attached to the work (an example is provided in the Appendix below). "Derivative Works" shall mean any work, whether in Source or Object form

of an entity class are detected by ObjectDB. New entity objects have to be stored in the new class schema, and old entity objects, which were stored previously in the old class schema, have to be converted to the new schema. Note: In client-server mode the ObjectDB server must be restarted

Entity objects are in -memory instances of entity classes (persistable user defined classes), which can represent physical objects in the database. Managing an ObjectDB Object Database using JPA ... . In this state the object is not yet associated with an EntityManager and has no representation in

not need to be enhanced. Enhancement improves efficiency in three ways: Enhanced code enables ... (as explained in   chapter 3 ). This is done by adding special code to enhanced classes ... reflection. Command Line Enhancement ObjectDB Enhancer is a Java console application. It is contained in

Every entity object that is stored in the database has a primary key. Once assigned, the primary key cannot be modified. It represents the entity object as long as it exists in the database. As ... that is absent from other object oriented databases. Entity Identification Every entity object in

fills at runtime in a form that contains many optional fields - is expected to be cleaner when using ... (both methods are equivalent). In the example above a  CriteriaQuery instance is created for representing the built query. Then a Root  instance is created to define a range variable in the FROM

Queries are represented in JPA 2 by two interfaces - the old Query interface, which was the only interface available for representing queries in JPA 1, and the new TypedQuery interface that was introduced in JPA 2. The TypedQuery interface extends the Query interface. In JPA 2 the Query interface

). @PostPersist - after storing a new entity in the database (during commit or flush ). @PostLoad ... the EntityManager . @PostUpdate - after updating an entity in the database (during commit or flush ). @PreRemove - when an entity is marked for removal in the EntityManager. @PostRemove

on the server side and in embedded mode. The default configuration file contains the following element ... of a page in a database file. The default 2KB is appropriate for most applications. The element ... is much faster in writing data to a database, but true might be safer in production. By default, the recovery

the ability to use almost any valid JPQL expression in SELECT clauses. Specifying the required query results more precisely can improve performance and in some cases can also reduce the amount of Java ... the "SELECT *" expression (which is commonly used in SQL). Projection of Path Expressions JPQL

(); These methods can be invoked in a single expression with getResultList since the setter methods in Query and TypedQuery support method chaining (by returning the query object ... of other EntityManager instances). JPA implementations can easily make uncommitted changes visible in simple JPA

. Having an SQL-like syntax in JPA queries is an important advantage because SQL is a very powerful query ... and easier to use in Java. JPQL Query Structure As with SQL, a JPQL SELECT query also consists of up to 6 clauses in the following format: SELECT ... FROM ... [WHERE ...] [GROUP BY ... [HAVING

. the broader scope of this cache makes it useful in applications that use many short term  EntityManager instances.  In addition to the EntityManager 's L1 cache and the EntityManagerFactory 's L2 ... client machines. Setting the Shared Cache The shared (L2) cache is configured in three scopes: Globally

The WHERE clause adds filtering capabilities to the FROM-SELECT structure. It is essential in any ... over all the Country objects in the database using the c range variable. Before passing these Country ... to function as a filter. The boolean expression in the WHERE clause, which is also known as

connections during their lifetime. For instance, in a web application it is common to establish a separate ... a persistence unit name. To use ObjectDB embedded directly in your application (embedded mode ... ; "objectdb:my-db.tmp" ). To use client server mode, a URL in the format objectdb://host:port/path

ObjectDB Server is a tool that manages ObjectDB databases in a separate dedicated process, making these databases accessible to client applications in other processes including ones on other remote machines. The main benefits in running an ObjectDB server and using the client-server mode

, the same database is managed on multiple machines (nodes), possibly in different geographic locations. This could help in achieving high availability, fault tolerance and prompt disaster recovery. In ... / Write operations. The other (slave) nodes in the cluster manage identical copies of the same database

is optional when using ObjectDB, but required by JPA. persistence.xml Persistence units are defined in a persistence.xml file, which has to be located in the META-INF directory in the classpath ... to instantiate an EntityManagerFactory in JPA (as explained in the JPA Overview section) requires