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SDB is a persistence layer for use with Apache Jena that uses an SQL database to store triples/quads.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.sdb.compiler;
/* H2 contribution from Martin HEIN (m#)/March 2008 */
/* SAP contribution from Fergal Monaghan (m#)/May 2012 */
import org.apache.jena.sdb.SDB ;
import org.apache.jena.sdb.Store ;
import org.apache.jena.sdb.core.SDBRequest ;
import org.apache.jena.sdb.util.StoreUtils ;
import org.apache.jena.shared.PrefixMapping ;
import org.apache.jena.sparql.algebra.Op ;
import org.apache.jena.sparql.core.Substitute ;
import org.apache.jena.sparql.engine.binding.Binding ;
import org.apache.jena.sparql.util.Context ;
public class SDBCompile
{
// ----- Compilation : Op -> SQL
public static Op compile(Store store, Op op)
{
return compile(store, op, null) ;
}
public static Op compile(Store store, Op op, Context context)
{
if ( context == null )
context = SDB.getContext() ;
SDBRequest request = new SDBRequest(store, (PrefixMapping)null, context) ;
return compile(store, op, null, context, request) ;
}
// And the main compilation algorithm.
// QueryCompilerMain does the bridge generation.
public static Op compile(Store store, Op op, Binding binding, Context context, SDBRequest request)
{
if ( binding != null && ! binding.isEmpty() )
op = Substitute.substitute(op, binding) ;
// Defaults are set in SDBCompile.compile
// LeftJoinTranslation = true ; -- Does the DB support general join expressions?
// LimitOffsetTranslation = false ; -- Does the DB grok the Limit/Offset SQL?
// DistinctTranslation = true ; -- Some DBs can't do DISTINCT on CLOBS.
if ( StoreUtils.isHSQL(store) )
{
request.LeftJoinTranslation = false ; // Does not deal with non-linear join trees.
request.DistinctTranslation = true ;
request.LimitOffsetTranslation = false ; // Does not cope with the nested SQL
}
if ( StoreUtils.isH2(store) )
{
request.LeftJoinTranslation = false ; // Does not deal with non-linear join trees.
request.DistinctTranslation = true ;
request.LimitOffsetTranslation = false ; // Does not cope with the nested SQL
}
// Any of these need fixing and testing ...
if ( StoreUtils.isDerby(store) )
{
request.LeftJoinTranslation = true ;
request.LimitOffsetTranslation = false ;
request.DistinctTranslation = false ;
}
if ( StoreUtils.isPostgreSQL(store) )
{
request.LeftJoinTranslation = true ;
request.LimitOffsetTranslation = true ;
request.DistinctTranslation = true ;
}
if ( StoreUtils.isMySQL(store) )
{
request.LeftJoinTranslation = true ;
request.LimitOffsetTranslation = true ;
request.DistinctTranslation = true ;
}
if ( StoreUtils.isSQLServer(store) )
{
request.LeftJoinTranslation = true ;
request.LimitOffsetTranslation = false ;
request.DistinctTranslation = false ;
}
if ( StoreUtils.isOracle(store) )
{
request.LeftJoinTranslation = true ;
request.LimitOffsetTranslation = false ;
request.DistinctTranslation = false ;
}
if ( StoreUtils.isDB2(store) )
{
request.LeftJoinTranslation = true ;
request.LimitOffsetTranslation = false ;
request.DistinctTranslation = false ;
}
if ( StoreUtils.isSAP(store) )
{
request.LeftJoinTranslation = true ;
request.LimitOffsetTranslation = true ;
request.DistinctTranslation = true ;
}
QueryCompiler queryCompiler = store.getQueryCompilerFactory().createQueryCompiler(request) ;
Op op2 = queryCompiler.compile(op) ;
return op2 ;
}
}