问题
I have a table named group_table in MySQL with only two columns user_group_id and group_id (both of them are of type VARCHAR). Both of these columns together form a composite primary key.
I need to execute a statement using a sub-select IN() to select rows based on a list of values passed to the query.
@Override
@SuppressWarnings("unchecked")
public List<GroupTable> getList(List<GroupTable> list)
{
CriteriaBuilder criteriaBuilder=entityManager.getCriteriaBuilder();
CriteriaQuery<GroupTable> criteriaQuery=criteriaBuilder.createQuery(GroupTable.class);
Root<GroupTable> root = criteriaQuery.from(entityManager.getMetamodel().entity(GroupTable.class));
criteriaQuery.where(root.in(list));
return entityManager.createQuery(criteriaQuery).getResultList();
}
The implementation produces the following query.
SELECT group_id,
user_group_id
FROM projectdb.group_table
WHERE ((?, ?) IN ((?, ?), (?, ?)))
/*Binding parameters.*/
bind => [null, null, ROLE_AAA, aaa, ROLE_BBB, aaa]
Please notice that the first two parameters which are about the composite key itself are null. They should be user_group_id and group_id respectively.
Why are they not substituted in the parameter list?
While I'm not interested in forming a composite primary key in a table, this is (likely) mandatory for JAAS I'm using for authentication.
In this scenario, the query returns the same list as it is supplied from the database which is needless in reality. I actually need this query for deletion of multiple rows.
回答1:
this is a missing feature in eclipse link. I have devlopped a patch for this
/** *****************************************************************************
* Copyright (c) 1998, 2013 Oracle and/or its affiliates. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Oracle - initial API and implementation from Oracle TopLink
* Nicolas Marcotte <nicolas.marcotte@usherbrooke.ca> - patch for IN on composite keys comming from expression builder
***************************************************************************** */
package org.eclipse.persistence.internal.expressions;
import java.io.*;
import java.util.*;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.eclipse.persistence.internal.helper.*;
import org.eclipse.persistence.internal.sessions.AbstractSession;
import org.eclipse.persistence.queries.*;
import org.eclipse.persistence.exceptions.*;
import org.eclipse.persistence.expressions.*;
import org.eclipse.persistence.internal.databaseaccess.*;
import org.eclipse.persistence.internal.sessions.AbstractRecord;
/**
* <p>
* <b>Purpose</b>: Expression SQL printer.
* <p>
* <b>Responsibilities</b>:<ul>
* <li> Print an expression in SQL format.
* <li> Replaces FIELD types with field names from the descriptor.
* <li> Replaces PARAMETER types with row or object values.
* <li> Calls accessor to print primitive types.
* </ul>
* <p>
* @author Dorin Sandu
* @since TOPLink/Java 1.0
*/
public class ExpressionSQLPrinter {
/**
* Stores the current session. The session accessor
* is used to print all the primitive types.
*/
protected AbstractSession session;
/**
* Stores the current platform to access platform specific functions.
*/
protected DatabasePlatform platform;
/**
* Stores the call being created.
*/
protected SQLCall call;
/**
* Stores the row. Used to print PARAMETER nodes.
*/
protected AbstractRecord translationRow;
/**
* Indicates whether fully qualified field names
* (owner + table) should be used or not.
*/
protected boolean shouldPrintQualifiedNames;
// What we write on
protected Writer writer;
/** Used for distincts in functions. */
protected boolean requiresDistinct;
// Used in figuring out when to print a comma in the select line
protected boolean isFirstElementPrinted;
private final ExpressionBuilder builder;
public ExpressionSQLPrinter(AbstractSession session, AbstractRecord translationRow, SQLCall call, boolean printQualifiedNames, ExpressionBuilder builder) {
this.session = session;
this.translationRow = translationRow;
this.call = call;
this.shouldPrintQualifiedNames = printQualifiedNames;
// reference session's platform directly if builder or builder's descriptor is null
if (builder == null || builder.getDescriptor() == null) {
this.platform = getSession().getPlatform();
} else {
this.platform = (DatabasePlatform) getSession().getPlatform(builder.getDescriptor().getJavaClass());
}
this.requiresDistinct = false;
this.builder = builder;
isFirstElementPrinted = false;
}
/**
* Return the call.
*/
public SQLCall getCall() {
return call;
}
/**
* INTERNAL:
* Return the database platform specific information.
*/
public DatabasePlatform getPlatform() {
return this.platform;
}
protected AbstractSession getSession() {
return session;
}
/**
* INTERNAL:
* Return the row for translation
*/
protected AbstractRecord getTranslationRow() {
return translationRow;
}
public Writer getWriter() {
return writer;
}
/**
* INTERNAL:
* Used in figuring out when to print a comma in the select clause
*/
public boolean isFirstElementPrinted() {
return isFirstElementPrinted;
}
public void printExpression(Expression expression) {
translateExpression(expression);
}
public void printField(DatabaseField field) {
if (field == null) {
return;
}
//start of patch 1
//resolve alias if is was not already done
if (builder.getTableAliases() != null) {
DatabaseTable keyAtValue = builder.getTableAliases().keyAtValue(field.getTable());
if (keyAtValue != null) {
field.setTableName(keyAtValue.getName());
}
}
//end of patch 1
try {
// Print the field using either short or long notation i.e. owner + table name.
if (shouldPrintQualifiedNames()) {
getWriter().write(field.getQualifiedNameDelimited(platform));
} else {
getWriter().write(field.getNameDelimited(platform));
}
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
public void printParameter(ParameterExpression expression) {
try {
final Logger logger = LogManager.getLogger();
getCall().appendTranslationParameter(getWriter(), expression, getPlatform(), getTranslationRow());
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
public void printParameter(DatabaseField field) {
getCall().appendTranslation(getWriter(), field);
}
public void printPrimitive(Object value) {
if (value instanceof Collection) {
printValuelist((Collection) value);
return;
}
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), value);
}
public void printNull(ConstantExpression nullValueExpression) {
if (session.getPlatform().shouldBindLiterals()) {
DatabaseField field = null;
Expression localBase = nullValueExpression.getLocalBase();
if (localBase.isFieldExpression()) {
field = ((FieldExpression) localBase).getField();
} else if (localBase.isQueryKeyExpression()) {
field = ((QueryKeyExpression) localBase).getField();
}
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), field);
} else {
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), null);
}
}
public void printString(String value) {
try {
getWriter().write(value);
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
public void printValuelist(Collection values) {
try {
getWriter().write("(");
Iterator valuesEnum = values.iterator();
while (valuesEnum.hasNext()) {
Object value = valuesEnum.next();
// Support nested arrays for IN.
if (value instanceof Collection) {
printValuelist((Collection) value);
} else if (value instanceof Expression) {
((Expression) value).printSQL(this);
//start of patch 2
} else if (value instanceof DatabaseField) {
printExpression(builder.getField((DatabaseField) value));
//end of patch 2
} else {
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), value);
}
if (valuesEnum.hasNext()) {
getWriter().write(", ");
}
}
getWriter().write(")");
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
/*
* Same as printValuelist, but allows for collections containing expressions recursively
*/
public void printList(Collection values) {
try {
getWriter().write("(");
Iterator valuesEnum = values.iterator();
while (valuesEnum.hasNext()) {
Object value = valuesEnum.next();
if (value instanceof Expression) {
((Expression) value).printSQL(this);
} else {
session.getPlatform().appendLiteralToCall(getCall(), getWriter(), value);
}
if (valuesEnum.hasNext()) {
getWriter().write(", ");
}
}
getWriter().write(")");
} catch (IOException exception) {
throw ValidationException.fileError(exception);
}
}
/**
* If a distinct has been set the DISTINCT clause will be printed.
* This is required for batch reading.
*/
public boolean requiresDistinct() {
return requiresDistinct;
}
protected void setCall(SQLCall call) {
this.call = call;
}
/**
* INTERNAL:
* Used in figuring out when to print a comma in the select clause
*/
public void setIsFirstElementPrinted(boolean isFirstElementPrinted) {
this.isFirstElementPrinted = isFirstElementPrinted;
}
/**
* If a distinct has been set the DISTINCT clause will be printed.
* This is required for batch reading.
*/
public void setRequiresDistinct(boolean requiresDistinct) {
this.requiresDistinct = requiresDistinct;
}
protected void setSession(AbstractSession theSession) {
session = theSession;
}
protected void setShouldPrintQualifiedNames(boolean shouldPrintQualifiedNames) {
this.shouldPrintQualifiedNames = shouldPrintQualifiedNames;
}
/**
* INTERNAL:
* Set the row for translation
*/
protected void setTranslationRow(AbstractRecord theRow) {
translationRow = theRow;
}
public void setWriter(Writer writer) {
this.writer = writer;
}
public boolean shouldPrintParameterValues() {
return getTranslationRow() != null;
}
protected boolean shouldPrintQualifiedNames() {
return shouldPrintQualifiedNames;
}
/**
* Translate an expression i.e. call the appropriate
* translation method for the expression based on its
* type. The translation method is then responsible
* for translating the subexpressions.
*/
protected void translateExpression(Expression theExpression) {
theExpression.printSQL(this);
}
}
The patch is delimited by //start of patch n and //end of patch n I will try to sumbmit it upstream but it might takes times
回答2:
Try this
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<GroupTable> cq = cb.createQuery(GroupTable.class);
Root<GroupTable> r = cq.from(GroupTable.class);
Expression<EntityPK> exp = r.get("id"); //EntityPK is your primary composite key class and id is the property name of primary key in GroupTable entity
Predicate predicate = exp.in(list);
cq.select(r).where(predicate);
entityManager.createQuery(cq).getResultList();
I have a following table with below structure
create table EntityA (
col1 integer not null,
col2 integer not null,
description varchar(255),
primary key (col1, col2)
)
Following are the entity and composite key classes
@Entity
public class EntityA implements Serializable {
@EmbeddedId
private EntityPK id;
private String description;
// getters, setteres
...........................
............................
}
@Embeddable
public class EntityPK implements Serializable {
private int col1;
private int col2;
// getters, setters, hashcode, equals etc
My test code is
CriteriaBuilder cb = em.getCriteriaBuilder();
CriteriaQuery<EntityA> cq = cb.createQuery(EntityA.class);
Root<EntityA> r = cq.from(EntityA.class);
Expression<EntityPK> exp = r.get("id");
Predicate predicate = exp.in(list);
cq.select(r).where(predicate);
em.createQuery(cq).getResultList();
The resulting SQL is
select
entitya0_.col1 as col1_0_,
entitya0_.col2 as col2_0_,
entitya0_.description as descript3_0_
from
EntityA entitya0_
where
entitya0_.col1=?
and entitya0_.col2=?
or entitya0_.col1=?
and entitya0_.col2=?
or entitya0_.col1=?
and entitya0_.col2=?
回答3:
You can use a field concatenation approach to solve the problem.
Create a method that returns the two fields you want to search in your DTO/Entity.
public String getField1Field2Concatenated() {
return field1+ field2;
}
List<String> ids = list.stream().map(r -> r.getField1Field2Concatenated()).collect(Collectors.toList());
You can concatenate two fields and do the search.
Select e from Entity e where concat(e.field1, c.field2) in (:ids)
If any of the fields are not text you can cast
Select e from Entity e where concat(cast(c.field1 as string), c.field2) in (:ids)
来源：https://stackoverflow.com/questions/24109412/in-clause-with-a-composite-primary-key-in-jpa-criteria