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more work on design docs for SQM and SQL AST

This commit is contained in:
Steve Ebersole 2019-11-25 17:14:21 -06:00
parent 0c6c8b4406
commit 293fc0fe54
2 changed files with 31 additions and 13 deletions
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6
design/sql-ast.adoc
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@ -2,7 +2,8 @@
Ultimately our goal here is to have a `JdbcOperation` object to be executed. Generally, that would look like this:
````
[source]
----
final SelectStatement sqlAst = ...;
final JdbcServices jdbcServices = sessionFactory.getJdbcServices();
@ -19,8 +20,7 @@ Ultimately our goal here is to have a `JdbcOperation` object to be executed. Ge
jdbcParameterBindings,
...
);
````
----
== The Tree

38
design/sqm.adoc
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@ -2,9 +2,13 @@
The Semantic Query Model (SQM) is Hibernate's representation of an HQL or Criteria query's semantic (meaning). This
representation is modeled as an "abstract syntax tree" (AST) - meaning it is a structured tree of nodes where each node
represrents an atomic piece of the query. E.g. `SqmSelectClause` represents the query's select clause as you might
imagine. That `SqmSelectClause` is ultimately a collection of one or more `SqmSelection` references representing the
individual selections to be returned from the query (called the domain results).
represents an atomic piece of the query. E.g. `SqmSelectClause` represents the query's select clause.
`SqmSelectClause` is ultimately a collection of one or more `SqmSelection` references representing the individual
selections to be returned from the query (called the domain results). Etc
All of these details are handled by the `QuerySqmImpl` implementation of `Query`. This is what Hibernate
uses for both HQL and Criteria queries.
== The Tree
@ -18,14 +22,14 @@ See the `design/type-system-domain.adoc` design doc. For details about this dom
The tree model is defined in the package `org.hibernate.query.sqm.tree`
== Building an SQM
== Building an SQM - HQL
`org.hibernate.query.hql.HqlTranslator#translate`
=== HQL
=== Criteria
== Building an SQM - Criteria
`org.hibernate.query.sqm.internal.SqmCriteriaNodeBuilder`
== Translating an SQM
@ -33,5 +37,19 @@ The tree model is defined in the package `org.hibernate.query.sqm.tree`
Generic support for walking over the SQM tree via the `org.hibernate.query.sqm.SemanticQueryWalker` contract.
More specialized support specifically for translating the SQM into a SQL AST is also defined by
`org.hibernate.query.sqm.sql.SqmToSqlAstConverter`. The document `design/sql-ast.adoc` for details about the SQL AST,
including its execution.
`org.hibernate.query.sqm.sql.SqmToSqlAstConverter`.
[source]
----
final SessionFactoryImplementor sessionFactory = ...;
final QueryEngine queryEngine = sessionFactory.getQueryEngine();
final SqmTranslatorFactory sqmTranslatorFactory = queryEngine.getSqmTranslatorFactory();
final SqmSelectTranslator sqmConverter = sqmTranslatorFactory.createSelectTranslator( ... );
final SqmSelectTranslation interpretation = sqmConverter.translate( sqm );
----
See the document `design/sql-ast.adoc` for details about the SQL AST, including its execution.