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. Applying changes to the database by calling the commit method. JPQL UPDATE queries provide an alternative way of updating entity objects. Unlike SELECT queries, which are used to retrieve data from the database, UPDATE queries do not retrieve data from the database, but when executed, update

Chapter 4 - JPA Queries (JPQL / Criteria)

The JPA Query Language (JPQL) can be considered as an object oriented version of SQL. Users ... well as how to use the JPA Criteria API, which provides an alternative way for building queries in JPA ... (named) queries. It explains how to use the relevant interfaces, annotations, enums and methods

JPA Query Expressions (JPQL / Criteria)

Query expressions are the foundations on which JPQL and criteria queries are built. Every query ... of JPQL / Criteria query expressions. Atomic Expressions The atomic query expressions are: JPQL / Criteria Variables JPQL / Criteria Parameters JPQL / Criteria Literals Every query expression consists

Criteria Query Selection and Results

and for representing query results as tuples. SELECT Clause Elements The content of the SELECT clause in a criteria query is represented by Selection: Because Selection is a super interface ... : See the SELECT in Criteria Queries section for more details and examples. ORDER BY Clause Elements Elements in

Criteria Query From Elements

The interfaces 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. Query variables are represented in criteria queries by descendant interfaces of the From interface: Range variables

Date and Time in JPQL and Criteria Queries

Date and time expressions may appear in JPQL queries: as date and time literals - e.g. {d '2011-12 ... that are evaluated to the date and time on the database server when the query is executed: CURRENT_DATE ... in Criteria Queries The CriteriaBuilder interface provides three factory methods for building date

Collections in JPQL and Criteria Queries

Collections may appear in JPQL queries: as parameters - when collections are assigned as arguments ... , which should be used for checking other collections, such as a collection that is passed to the query ... of collection, so in ObjectDB these operators are treated as synonyms. Criteria Query Collection

Literals in JPQL and Criteria Queries

literals should be used sparingly as queries that use parameters instead of literals ... values. Literals should only be embedded in JPQL queries when a single constant value is always used ... support for enum literals. Enum literals in JPQL queries use the ordinary Java syntax for enum

Strings in JPQL and Criteria Queries

String values may appear in JPQL queries in various forms: as string literals - e.g. 'abc', ''. as ... operator). Criteria Query String Expressions JPQL string operators and functions (which are described above) are available also as JPA criteria query expressions. The CriteriaBuilder interface provides

Numbers in JPQL and Criteria Queries

Numeric values may appear in JPQL queries in many forms: as numeric literals - e.g. 123, -12.5. as ... of any type and always returns a double value. Criteria Query Arithmetic Expressions JPQL arithmetic operators and functions (which are described above) are available also as JPA criteria query

Getting Started

ObjectDB is very easy to use. Follow the Getting Started Tutorial and the Quick Tour manual chapter and in minutes you may be able to write and run first Java programs against ObjectDB.

Prior knowledge or experience in database programming (SQL, JDBC, ORM, JPA, etc.) is not required, but some background in using the Java language is essential.

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