About FROM

manual

FROM clause (JPQL / Criteria API)

Explains how to use the FROM clause and JOIN expressions in a JPA/JPQL query. The FROM clause declares query identification variables that represent iteration ... FETCH Reserved Identifiers FROM and JOIN in Criteria Queries Range Variables ... JPQL does not provide a way to exclude descendant classes from iteration at the FROM clause level. JPA 2, however, adds support for ...

 
api-jpa

Criteria Query From Elements

Reference (JavaDoc) of JPA query criteria FROM clause interfaces, including From, Root, Join and Fetch.... in this group are in use for setting a criteria query FROM clause. Criteria Query Variables The FROM clause  in JPA queries (as in SQL) defines the query variables. ...

 
api-jpa

from(entityClass)

Create and add a query root corresponding to the given entity, forming a cartesian product with any existing roots.(Method of javax.persistence.criteria.AbstractQuery)

 
api-jpa

javax.persistence.criteria.From

Represents a bound type, usually an entity that appears in the from clause, but may also be an embeddable belonging to an entity in the from clause.(Interface of JPA)

 
manual

JPA Query Structure (JPQL / Criteria)

Explains the structure of a JPQL query, which consists of 6 clauses: SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY.... and return entity objects rather than just field values from database tables, as with SQL. That makes JPQL more object oriented ... in the following format: SELECT ... FROM ... [ WHERE ... ] [ GROUP BY ...

 
manual

Paths and Types in JPQL and Criteria API

Explains how to use object expressions (path navigation, type) in JPA/JPQL.... types of expressions: Variables - FROM identification variables and SELECT result variables. ... as arguments. Path expressions that navigate from one object to another. Instances of user defined persistable ...

 
forum_thread

Delete object from collection versus delete from JPQL

I'm a newbie, so this is a pretty fundamental question. I'm not sure if there is a bi-directional relationship between the objects in memory and ObjectDB.  I know I can modify the objects and use persist() to write them to the database.  But does running a JPQL update or delete alter the in-memory objects? There are cases where the JPQL syntax is more expressive than operating on a collection, but I'm not sure if that will alter my program state.  Will it? Thanks, Lee  #1 2014-03-24 22:25 I'm a newbie, so this is a pretty fundamental question. I'm not sure if there is a bi-directional ...

 
manual

Chapter 4 - JPA Queries (JPQL / Criteria)

Describes the Java Persistence Query Language (JPQL), the JPA Criteria API, and explains how to use queries in JPA.... by describing the main clauses of JPQL queries (SELECT, FROM, WHERE, GROUP BY, HAVING, ORDER BY): JPA Query Structure ...

 
api-jpa

from(entity)

Create and add a query root corresponding to the given entity, forming a cartesian product with any existing roots.(Method of javax.persistence.criteria.AbstractQuery)

 
api-jdo

javax.jdo.PersistenceManager

PersistenceManager is the primary interface for JDO-aware application components.(Interface of JDO)