At this tutorial we’ve explained the concept of entity identification. Entity identification is the process in which the Java Persistence Implementation identify an entity uniquely from set of entities that belong to the same type on a memory level or a database level. Each entity that located in the persistence context must has a unique …
Java EE
JPA Annotations – @Temporal
@Temporal annotation in JPA implementation can only be used with the fields and property get methods. Also, this annotation can be specified for the persistent fields or properties java.util.Data or java.util.Calendar. This annotation is available since the release of JPA 1.0. @Temporal solves the one of the major issue of converting the date and time …
JSTL Function fn:join()
The <fn:join()> is a string function of JSP Standard tag Library(JSTL).This function is used for joining all the elements of an array into a string with a specified operator and returns the output. This function returns string with all the elements of an array separated by a separator. Syntax of <fn:join()> function Example of <fn:join()> …
Eclipselink / JPA – Abstract Entity And Non-Entity Classes In The Entity Inheritance
When we’ve discussed the inheritance and mapped superclasses concepts in the previous tutorials, we are avoiding concepts that could confuse the readers or makes misunderstanding for them. Most of the clarified examples didn’t provide an Abstract Entity as a target entities that can be managed by the entity manager. On the contrary an Abstract Entity was only …
EclipseLink / JPA Annotations – @AttributeOverride And @AssociationOverride
At this tutorial we’ll introduce using of @AttributeOverride and @AssocationOverride that mentioned intentionally at the @MappedSuperclass tutorial. As you’ve remembered at @MappedSuperclass annotation tutorial, we’ve mentioned at the Database Design section the possibility of using @AttributeOverride and @AssociationOverride to override the attributes and associations that inherited from the mapped superclass. An entity can inherit a persistent entity state and …
JSTL XML x:parse Tag
The <x: parse> tag is used to parse the xml content and the result will be stored in specified variable. Syntax Of <x: parse> Tag Attributes Of <x: parse> Tag Attributes Description doc Specifies that source XML document to be parsed. systemId Specifies the system identifier in xml document for parsing. filter Filter object is …
JSTL SQL sql:query Tag
The <sql:query> tag is used to execute a query specified in sql attribute or in the body. It executes SQL statement and saves in the scoped variable. It executes sql query and stores result in specified variable. Attributes of <sql: query>Tag sql: It specifies SQL command that has to be executed. var: It is used …
JSTL SQL Tags Library
The JSTL SQL tags help us interact with the relational databases such as Oracle, MySql and more. Syntax for JSTL SQL Tag The JSTL SQL Tags <sql:setDataSource >: It is used for creating data source that is to be accessed by executing a query. <sql:query >: It is used to execute a query specified in …