 39 | Date and time expressions may appear in JPQL queries: as date and time literals - e.g. {d '2011-12 ... expressions - in navigation to persistent date and time fields. as results of predefined JPQL current date and time functions. Current Date and Time JPA defines special JPQL expressions |
39 | The CriteriaBuilder interface provides two factory methods for building literal expressions. Ordinary Literals The main method, literal, takes a Java object and returns a literal expression. For example:
// Boolean literals:
Expression t = cb.literal(true);
Expression f |
37 | the first letters as result. ObjectDB is very flexible in allowing JPQL expressions anywhere in ... . Only identification variables and path expressions are currently supported in the GROUP BY clause by all the JPA ... that are in use by countries in that group. The DISTINCT keyword in a COUNT aggregate expression, as |
34 | and expressions that include an unknown value are evaluated as unknown, i.e. to NULL. IS [NOT] NULL ... which are provided by JPQL (and SQL):
c.president IS NULL
c.president IS NOT NULL The expressions ... ) expressions:
c.president == null
c.president != null Comparable Data Types Comparison is supported |
32 | , the range variable, c, is also used in the SELECT clause as the query result expression ... on how to set criteria query clauses and build criteria expressions. Running this query requires ... , including in the context of string based JPQL queries. Criteria Query Expressions JPA query clauses |
31 | expressions out of simple JPQL boolean expressions. Logical Operators ObjectDB supports 2 sets ... part of its JDO support. Criteria Query Logical Operators Boolean Expressions and Predicates Boolean expressions are represented in criteria queries by Expression and descendant interfaces |
27 | , the WHERE clause gets an opportunity to function as a filter. The boolean expression in ... objects for which the predicate expression evaluates to TRUE are passed to the SELECT clause ... , making indexes even more essential. JPQL Expressions in WHERE The above queries demonstrate |
27 | at the WHERE clause level by using a type expression. For example, in the following query, c iterates ... variable that serves as a root and additional join variables that are bound to path expressions. Join variables can also be bound to path expressions that are based on other join variables |
25 | . as path expressions - in navigation to persistent collection fields. IS [NOT] EMPTY The IS [NOT ... Expressions JPQL collection operators and functions (which are described above) are available also as JPA criteria query expressions. The CriteriaBuilder interface provides factory methods for building |
24 | javax.persistence.criteria Interface Subquery Superinterfaces: AbstractQuery, Expressionexpression as its selection item. Since: JPA 2.0 Selection alias(String ... Returns: selection item Since: JPA 2.0 Expression as(Class type) Perform a typecast |