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Literals in JPQL and Criteria Queries

Literals in JPQL, as in Java, represent constant values. JPQL supports various types of literals including NULL, boolean literals (TRUE and FALSE), numeric literals (e.g. 100), string literals (e.g. 'abc'), enum literals (e.g. mypackage.MyEnum.MY_VALUE) and entity type literals (e.g. Country). JPQL


Method javax.persistence.criteria.CriteriaBuilder Expression<T> literal( T value ) Create an expression for a literal. Parameters: value - value represented by the expression Returns: expression literal Throws: IllegalArgumentException - if value is null Since: JPA 2.0

Query Parameters in JPA

for more details. Parameters vs. Literals Following is a third version of the same method, this time ... for the queried name, the new method embeds the name as a String literal. There are a few drawbacks to using literals rather than parameters in queries. First of all, the query is not reusable. Different

JPA Query Expressions (JPQL / Criteria)

/ Criteria Variables JPQL / Criteria Parameters JPQL / Criteria Literals Every query expression consists ... expressions are provided as follows: Literals and Dates (literal, nullLiteral, currentDate, ...). Paths

Strings in JPQL and Criteria Queries

String values may appear in JPQL queries in various forms: as string literals - e.g. 'abc', ''. as ... literal). For example: c.name LIKE '_r%' is TRUE for 'Brazil' and FALSE for 'Denmark' c.name LIKE ... "); Expression<Integer> l3 = cb.locate(path, param, cb.literal(2)); Expression<Integer> l4 = cb.locate

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 parameters - when numeric values are assigned as arguments. as path expressions - in navigation ... (cb.literal(100)); // SQRT(expression) As shown above, a number can always be converted to a numeric expression by using the literal method.

Paths and Types in JPQL and Criteria API

. The Country literal represents the Country entity class. The TYPE operator returns the actual type ... is not Country. Predicate p = cb.notEqual(e.type(), cb.literal(Country.class)); In ... a root or a join) and the entity type Country (a criteria literal).

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 '2011-12-31'}, {t '23:59:59'}. as parameters - when date and time values are assigned as arguments. as path ... (); // both Unlike constant date literals which are built once on the client side, the current date and time

Comparison in JPQL and Criteria API

); // BETWEEN Predicate b1 = cb.between(name, nameParam, cb.literal("Y")); Predicate b2 = cb.between(name, "X", "Y"); Predicate b3 = cb.between(area, areaParam, cb.literal(2000000

[ODB1] Chapter 7 - JDOQL Queries

that are discussed later in this chapter. Literals All types of Java literals are supported by JDOQL, as demonstrated by the following table: Literal Type Samples of valid literals in JDOQL int 2003, -127, 0 ... 7.3), parameters could be used instead of constant literals to make queries more generic. Parameter

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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