Package org.hibernate.query.sqm

@Incubating(since="6.2") package org.hibernate.query.sqm

This package defines a semantic model of HQL queries.

Semantic Query Model (SQM)

An SQM is a tree representing the semantic interpretation of a query. It's "semantic" in the sense that it contains more information than a simple syntax tree.

HQL

HQL is interpreted as an SQM with the help of an ANTRL-generated parser. The class SemanticQueryBuilder is responsible for visiting the syntax tree produced by the parser and building an SQM.

Criteria queries

The SQM tree nodes directly implement the JPA criteria query contracts. For example, SqmFrom implements From.

Our implementation of the JPA CriteriaBuilder interface is SqmCriteriaNodeBuilder. It instantiates SQM nodes and arranges them into SQM tree using the standard operations for building a JPA criteria query.

Transforming SQM to SQL

The package

invalid reference

org.hibernate.sql.ast

defines an AST representing SQL. To generate SQL from SQM, we must transform the SQM tree to a SQL AST tree. This process is described here, and is handled by a StandardSqmTranslator and a SqlAstTranslator.

API Note:

This entire package is in an incubating state.

Related Packages

Package	Description
org.hibernate.query	Everything related to HQL/JPQL, native SQL, and criteria queries.
org.hibernate.query.sqm.function	An SPI for defining, registering, and rendering functions in HQL.
org.hibernate.query.sqm.spi	SPI-level SQM contracts

Class	Description
AliasCollisionException	Occurs when the HQL query declares a duplicate identification variable in the from clause, or a duplicate result column alias in the select clause.
BinaryArithmeticOperator	Enumeration of standard binary arithmetic operators
CastType	Defines the set of basic types which should be accepted by the cast() function on every platform.
ComparisonOperator	Enumerates the binary comparison operators.
EntityTypeException	Indicates that a reference to an entity, that is, a given entity name or Java class object, did not resolve to a known mapped entity type.
InterpretationException	Represents a generic unhandled problem which occurred while translating HQL/JPQL.
LiteralNumberFormatException
ParsingException	Occurs when an unexpected condition is encountered while interpreting the output of the HQL parser.
PathElementException	Indicates that an element of a path did not resolve to a mapped program element.
SetOperator	The SQL set operators.
StrictJpaComplianceViolation	Indicates violations of strict JPQL syntax while strict JPQL syntax checking was enabled.
StrictJpaComplianceViolation.Type
TerminalPathException	Indicates an attempt to dereference a terminal path (usually a path referring to something of basic type)
TreatException	Indicates a problem with a TREAT usage
TrimSpec	Variations of the trim() function.
UnaryArithmeticOperator	Enumerates the unary prefix operators.
UnknownEntityException	Indicates a failure to resolve an entity name in HQL to a known mapped entity type.
UnknownPathException	Indicates a failure to resolve an element of a path expression in HQL/JPQL.