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The JPA Criteria API provides an alternative way for defining JPA queries, which is mainly useful for building dynamic queries whose exact structure is only known at runtime. JPA Criteria API vs JPQL JPQL queries are defined as

The Query">Query interface defines two methods for running SELECT queries: Query/getSingleResult">Query.getSingleResult - for use when exactly one result object is expected

The Query">Query and query/execute">query execution if invoked before a query ... a portion of a large query result list (hiding anything outside that window). The

Query parameters enable the definition of reusable queries. Such queries can be executed with different parameter values to retrieve different results. Running the same query multiple times with different parameter values (arguments) is more efficient than using a new query string

A named query is a statically defined query with a predefined unchangeable query string. Using named queries instead of dynamic queries may improve code organization by separating the JPQL query strings from the Java code. It also enforces the use of query 

The syntax of the Java Persistence Query Language (JPQL) is very similar to the syntax of SQL. Having an SQL-like syntax in JPA queries is an important advantage because SQL is a very powerful query language and many developers are already familiar with it. The main difference

Queries are represented in JPA 2 by two interfaces - the old Query">Query interface, which was the only interface available for representing queries in JPA 1, and the new TypedQuery interface

Query expressions are the foundations on which JPQL and criteria queries are built. Every query consists of query/jpql/structure">clauses - SELECT, FROM, WHERE, GROUP BY, HAVING and ORDER BY, and each clause consists of JPQL / Criteria query expressions

Queries are represented in JPA by the Query and TypedQuery interfaces: queries" select="Query|TypedQuery"> The query/api">JPA Query API section (in chapter 4

. When a more selective retrieval is needed, JDOQL (JDO Query Language) is used. JDOQL for JDO is like SQL ... JDOQL query has the following three components: A candidate collection ... The query result is a subset of objects from the candidate collection