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Difference between revisions of "EclipseLink/DesignDocs/312146"

(API)
(Project overview)
Line 29: Line 29:
  
 
Other JPQL enhancements:
 
Other JPQL enhancements:
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=243698 allow qualified class names in from clause]
+
* BUG#243698 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=243698 allow qualified class names in from clause]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=293775 allow alias on join fetch]
+
* BUG#293775 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=293775 allow alias on join fetch]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=315087 support for cast function]
+
* BUG#315087 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=315087 support for cast function]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=333645 group by fails in in]
+
* BUG#333645 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=333645 group by fails in in]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=276147 support union and intersect]
+
* BUG#276147 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=276147 support union and intersect]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=305187 support platform independent functions and custom operators]
+
* BUG#305187 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=305187 support platform independent functions and custom operators]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=321722 support nested join fetches]
+
* BUG#321722 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=321722 support nested join fetches]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=321724 support connect by]
+
* BUG#321724 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=321724 support connect by]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=321725 support common functions]
+
* BUG#321725 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=321725 support common functions]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=350597 JPA 2.1 sub select in functions, having, select, from]
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* BUG#350597 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=350597 JPA 2.1 sub select in functions, having, select, from]
 
* support IN with nested arrays
 
* support IN with nested arrays
 
* support literal key word
 
* support literal key word
 
* support table and column references
 
* support table and column references
 
* support asOf
 
* support asOf
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=246356 support inner joins in from clause]
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* BUG#246356 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=246356 support inner joins in from clause]
  
 
Other JPQL bugs:
 
Other JPQL bugs:
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=346729 incorrect SQL for distinct]
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* BUG#346729 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=346729 incorrect SQL for distinct]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=331124 join to element collection does not work]
+
* BUG#331124 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=331124 join to element collection does not work]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=331969 join ignored]
+
* BUG#331969 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=331969 join ignored]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=347562 group by ignored] [https://bugs.eclipse.org/bugs/show_bug.cgi?id=227347]
+
* BUG#347562 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=347562 group by ignored] [https://bugs.eclipse.org/bugs/show_bug.cgi?id=227347]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=300625 duplicate join in sub select]
+
* BUG#300625 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=300625 duplicate join in sub select]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=267767 package with order fails to parse]
+
* BUG#267767 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=267767 package with order fails to parse]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=301905 stack overflow parsing query]
+
* BUG#301905 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=301905 stack overflow parsing query]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=320541 join of map fails]
+
* BUG#320541 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=320541 join of map fails]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=326848 plus not aliasable]
+
* BUG#326848 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=326848 plus not aliasable]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=327848 sub-string fails]
+
* BUG#327848 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=327848 sub-string fails]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=328378 element collection fails with in]
+
* BUG#328378 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=328378 element collection fails with in]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=245652 count distinct fails]
+
* BUG#245652 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=245652 count distinct fails]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=259867 bad sql for in] [https://bugs.eclipse.org/bugs/show_bug.cgi?id=243384] [https://bugs.eclipse.org/bugs/show_bug.cgi?id=314025]
+
* BUG#259867, 243384, 314025 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=259867 bad sql for in] [https://bugs.eclipse.org/bugs/show_bug.cgi?id=243384] [https://bugs.eclipse.org/bugs/show_bug.cgi?id=314025]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=301741 jpql sub selects incorrect]
+
* BUG#301741 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=301741 jpql sub selects incorrect]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=307412 member of fails]
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* BUG#307412 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=307412 member of fails]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=354344 concat fails in subquery]
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* BUG#354344 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=354344 concat fails in subquery]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=303268 expression order in jpql causes error]
+
* BUG#303268 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=303268 expression order in jpql causes error]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=303767 join fetch ignored]
+
* BUG#303767 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=303767 join fetch ignored]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=357843 dot removes outer join]
+
* BUG#357843 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=357843 dot removes outer join]
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=275449 is not null should be used]
+
* BUG#275449 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=275449 is not null should be used]
* from clause not used in select or where is omitted
+
* from clause alias not used in select clause or where clause is omitted
 
* object parameters on left
 
* object parameters on left
* [https://bugs.eclipse.org/bugs/show_bug.cgi?id=362063 Nested subselects]
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* BUG#362063 - [https://bugs.eclipse.org/bugs/show_bug.cgi?id=362063 Nested subselects]
  
 
= Concepts =
 
= Concepts =

Revision as of 10:23, 6 February 2012

Design Specification: Enhanced JPQL

ER 312146

Feedback

Document History

Date Author Version Description & Notes
2011-10-04 James 0.1 Draft

Project overview

JPQL currently offers a sub-set of SQL functionality. Some queries that are possible using SQL cannot be defined using JPQL.

It is desired to make EclipseLink's JPQL support be more complete of what is possible in SQL.

A key requirement from users (#1 voted enhancement) is to have ON clause support in JPQL.

Other missing features of SQL could also be added to JPQL, such as sub selects in the SELECT from FROM clauses, and enhanced function support.

Other JPQL enhancements:

Other JPQL bugs:

Concepts

ON clause : the SQL clause part of the FROM clause that defines how to tables are joined, this can be used for both joins and outer joins, but is required for outer joins.

outer join : A join where if a row in the source table has no joined rows in the target table it is still included in the join result with a null row for the target table.

ANTRL : Third party library currently used in EclipseLink for parsing JPQL.

SQL : SQL 2003 BNF

Hermes : New JPQL parser developed by Dali project for parsing JPQL at design time. Currently included in EclipseLink SVN, but not currently used.

Requirements

  • Support additional ON clause for a relationship join.
  • Support an ON clause on the join for two independent objects.

Design Constraints

  • Outer join capabilities differ in different databases.
  • SQL capabilities differ in different databases.

Functionality

  • Extend ObjectExpression to support an onClause, must normalize and copy expression accordingly.
  • Allow ExpressionBuilders and other Expressions to be added to nonFetchJoinExpressions in ObjectLevelReadQuery.
  • Add support for having SubSelectExpressions in SQLSelectStatement's fields and print/normalize accordingly.
  • Added new FromSubSelectExpression to allow SubSelectExpressions to be contained an aliased in a SQLSelectStatement's from clause.
  • Added new FromAliasExpression to allow get() to be used from a FromSubSelectExpression and treated as a QueryKeyExpression aliasing one of the items in the sub-select.
  • Added support to FunctionExpression and RelationExpression to support object comparisons with IN. For composite ids as parameters arrayed INs are used, this requires database specific support.
  • Added support for count distinct with composite ids for MySQL and supporting databases.

Testing

ON clause needs Expression tests in core testing and JPQL tests in JPA testing. Testing both 1-1, 1-m, relationship and parallel.

  • Added ON clause tests to Expression outerJoin core tests (both inner and outer joins tested).
  • Added FROM and SELECT sub-select tests to Expression subSelects core tests.

API

JPQL

  • ON
    • Select e from Employee e left join e.address a on (a.city = 'Ottawa')
    • Select e from Employee e left join Project p on (p.teamLeader = e)
  • Sub-select
    • Select e.id, (Select a.city from Address a where e.address = a) from Employee e
    • Select e.id, a2.city from Employee e, (Select a.city from Address a) a2
  • IN / NOT IN
    • Select e from Employee e where e.address in (Select a from Address a where city = 'Ottawa')
    • Select e from Employee e join e.phones p where p in :phones
    • Select e from Employee e join e.phones p where p in (:phone1, :phone2)
    • Select e from Employee e where e.address = (Select a from Address a where street = '27 Hastings')
  • ORDER BY (order by objects, Id or all fields for embeddables)
    • Select e from Employee e order by e.address
    • Select e from Employee e order by e.period

Native API

  • Expression
    • join(Expression target, Expression onClause)
    • leftJoin(Expression target, Expression onClause)
    • getAlias(Expression subSelect)
  • ObjectLevelReadQuery
    • addNonFetchJoin(Expression)

Examples:

// ON
ExpressionBuilder employee = new ExpressionBuilder();
Expression address = employee.getAllowingNull("address");
employee.leftJoin(address, address.get("city").equal("Ottawa"));
ReadAllQuery query = new ReadAllQuery(Employee.class, employee);
query.addNonFetchJoin(address);
 
// ON
ExpressionBuilder employee = new ExpressionBuilder(Employee.class);
ExpressionBuilder project = new ExpressionBuilder(Project.class);
employee.join(project, project.get("teamLeader").equal(employee));
ReadAllQuery query = new ReadAllQuery(Employee.class, employee);
query.addNonFetchJoin(project);
 
// SELECT SUB-SELECT
ExpressionBuilder employee = new ExpressionBuilder(Employee.class);
ExpressionBuilder address = new ExpressionBuilder(Address.class);
ReportQuery subQuery = new ReportQuery(Address.class, address);
subQuery.addAttribute("city");
subQuery.setSelectionCriteria(employee.get("address").equal(a));
ReportQuery query = new ReportQuery(Employee.class, employee);
query.addAttribute("id");
query.addItem("city", employee.subQuery(subQuery));
 
// FROM SUB-SELECT
ExpressionBuilder employee = new ExpressionBuilder(Employee.class);
ExpressionBuilder address = new ExpressionBuilder(Address.class);
ReportQuery subQuery = new ReportQuery(Address.class, address);
subQuery.addAttribute("city");
subQuery.setSelectionCriteria(employee.get("address").equal(a));
Expression a2 = employee.getAlias(employee.subQuery(subQuery));
ReportQuery query = new ReportQuery(Employee.class, employee);
query.addNonFetchJoin(a2);
query.addAttribute("id");
query.addItem("city", a2.get("city"));

Config files

Documentation

Need to document our BNF, example queries and support beyond JPA 2.0/2.1 in query section.

Open Issues

Issue # Owner Description / Notes
1 Which JPQL parser should be used ANTLR or Hermes?

Decisions

Issue Description / Notes Decision

Future Considerations

  • Other JPQL enhancements.
  • Criteria support.