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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: Ultimately our goal here is to have a `JdbcOperation` object to be executed. Generally, that would look like this:
```` [source]
----
final SelectStatement sqlAst = ...; final SelectStatement sqlAst = ...;
final JdbcServices jdbcServices = sessionFactory.getJdbcServices(); final JdbcServices jdbcServices = sessionFactory.getJdbcServices();
@ -19,8 +20,7 @@ Ultimately our goal here is to have a `JdbcOperation` object to be executed. Ge
jdbcParameterBindings, jdbcParameterBindings,
... ...
); );
----
````
== The Tree == 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 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 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 represents an atomic piece of the query. E.g. `SqmSelectClause` represents the query's select clause.
imagine. That `SqmSelectClause` is ultimately a collection of one or more `SqmSelection` references representing the `SqmSelectClause` is ultimately a collection of one or more `SqmSelection` references representing the individual
individual selections to be returned from the query (called the domain results). 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 == 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` 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 == Building an SQM - Criteria
=== Criteria
`org.hibernate.query.sqm.internal.SqmCriteriaNodeBuilder`
== Translating an SQM == 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. 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 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, `org.hibernate.query.sqm.sql.SqmToSqlAstConverter`.
including its execution.
[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.