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DB2iLegacyDialect.java
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DB2iLegacyDialect.java
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/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.community.dialect;
import org.hibernate.boot.model.FunctionContributions;
import org.hibernate.dialect.DatabaseVersion;
import org.hibernate.dialect.function.CommonFunctionFactory;
import org.hibernate.dialect.identity.DB2390IdentityColumnSupport;
import org.hibernate.dialect.identity.DB2IdentityColumnSupport;
import org.hibernate.dialect.identity.IdentityColumnSupport;
import org.hibernate.dialect.pagination.FetchLimitHandler;
import org.hibernate.dialect.pagination.LegacyDB2LimitHandler;
import org.hibernate.dialect.pagination.LimitHandler;
import org.hibernate.dialect.sequence.DB2iSequenceSupport;
import org.hibernate.dialect.sequence.NoSequenceSupport;
import org.hibernate.dialect.sequence.SequenceSupport;
import org.hibernate.dialect.unique.AlterTableUniqueIndexDelegate;
import org.hibernate.dialect.unique.SkipNullableUniqueDelegate;
import org.hibernate.dialect.unique.UniqueDelegate;
import org.hibernate.engine.jdbc.dialect.spi.DialectResolutionInfo;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.mapping.Column;
import org.hibernate.sql.ast.SqlAstTranslator;
import org.hibernate.sql.ast.SqlAstTranslatorFactory;
import org.hibernate.sql.ast.spi.StandardSqlAstTranslatorFactory;
import org.hibernate.sql.ast.tree.Statement;
import org.hibernate.sql.exec.spi.JdbcOperation;
import java.util.List;
/**
* An SQL dialect for DB2 for iSeries previously known as DB2/400.
*
* @author Peter DeGregorio (pdegregorio)
* @author Christian Beikov
*/
public class DB2iLegacyDialect extends DB2LegacyDialect {
final static DatabaseVersion DB2_LUW_VERSION9 = DatabaseVersion.make( 9, 0);
public DB2iLegacyDialect(DialectResolutionInfo info) {
this( info.makeCopy() );
registerKeywords( info );
}
public DB2iLegacyDialect() {
this( DatabaseVersion.make(7) );
}
public DB2iLegacyDialect(DatabaseVersion version) {
super(version);
}
@Override
public void initializeFunctionRegistry(FunctionContributions functionContributions) {
super.initializeFunctionRegistry(functionContributions);
if ( getVersion().isSameOrAfter( 7, 2 ) ) {
CommonFunctionFactory functionFactory = new CommonFunctionFactory(functionContributions);
functionFactory.listagg( null );
functionFactory.inverseDistributionOrderedSetAggregates();
functionFactory.hypotheticalOrderedSetAggregates_windowEmulation();
}
}
@Override
public DatabaseVersion getDB2Version() {
return DB2_LUW_VERSION9;
}
@Override
protected UniqueDelegate createUniqueDelegate() {
//TODO: when was 'create unique where not null index' really first introduced?
return getVersion().isSameOrAfter(7, 1)
//use 'create unique where not null index'
? new AlterTableUniqueIndexDelegate(this)
//ignore unique keys on nullable columns in earlier versions
: new SkipNullableUniqueDelegate(this);
}
@Override
public String getCreateIndexString(boolean unique) {
// we only create unique indexes, as opposed to unique constraints,
// when the column is nullable, so safe to infer unique => nullable
return unique ? "create unique where not null index" : "create index";
}
@Override
public String getCreateIndexTail(boolean unique, List<Column> columns) {
return "";
}
@Override
public boolean supportsDistinctFromPredicate() {
return true;
}
/**
* No support for sequences.
*/
@Override
public SequenceSupport getSequenceSupport() {
return getVersion().isSameOrAfter(7, 3)
? DB2iSequenceSupport.INSTANCE : NoSequenceSupport.INSTANCE;
}
@Override
public String getQuerySequencesString() {
if ( getVersion().isSameOrAfter(7,3) ) {
return "select distinct sequence_name from qsys2.syssequences " +
"where current_schema='*LIBL' and sequence_schema in (select schema_name from qsys2.library_list_info) " +
"or sequence_schema=current_schema";
}
else {
return null;
}
}
@Override
public LimitHandler getLimitHandler() {
return getVersion().isSameOrAfter(7, 3)
? FetchLimitHandler.INSTANCE : LegacyDB2LimitHandler.INSTANCE;
}
@Override
public IdentityColumnSupport getIdentityColumnSupport() {
return getVersion().isSameOrAfter(7, 3)
? DB2IdentityColumnSupport.INSTANCE
: DB2390IdentityColumnSupport.INSTANCE;
}
@Override
public boolean supportsSkipLocked() {
return true;
}
@Override
public boolean supportsLateral() {
return getVersion().isSameOrAfter( 7, 1 );
}
@Override
public boolean supportsRecursiveCTE() {
return getVersion().isSameOrAfter( 7, 1 );
}
@Override
public SqlAstTranslatorFactory getSqlAstTranslatorFactory() {
return new StandardSqlAstTranslatorFactory() {
@Override
protected <T extends JdbcOperation> SqlAstTranslator<T> buildTranslator(
SessionFactoryImplementor sessionFactory, Statement statement) {
return new DB2iLegacySqlAstTranslator<>( sessionFactory, statement, getVersion() );
}
};
}
}