Fix Sybase Connection#getSchema() throws an exception

(cherry picked from commit aaba476)

Author: dreab8

hibernate-core/src/main/java/org/hibernate/dialect/SybaseDialect.java

@@ -6,8 +6,14 @@
  */
 package org.hibernate.dialect;
 
+import java.sql.DatabaseMetaData;
+import java.sql.SQLException;
 import java.sql.Types;
 
+import org.hibernate.engine.jdbc.env.spi.IdentifierCaseStrategy;
+import org.hibernate.engine.jdbc.env.spi.IdentifierHelper;
+import org.hibernate.engine.jdbc.env.spi.IdentifierHelperBuilder;
+import org.hibernate.engine.jdbc.env.spi.NameQualifierSupport;
 import org.hibernate.type.descriptor.sql.BlobTypeDescriptor;
 import org.hibernate.type.descriptor.sql.ClobTypeDescriptor;
 import org.hibernate.type.descriptor.sql.SqlTypeDescriptor;
@@ -48,4 +54,21 @@ public String getNullColumnString() {
 	public String getCurrentSchemaCommand() {
 		return "select db_name()";
 	}
+
+	@Override
+	public IdentifierHelper buildIdentifierHelper(IdentifierHelperBuilder builder, DatabaseMetaData dbMetaData)
+			throws SQLException {
+		if ( dbMetaData == null ) {
+			builder.setUnquotedCaseStrategy( IdentifierCaseStrategy.MIXED );
+			builder.setQuotedCaseStrategy( IdentifierCaseStrategy.MIXED );
+		}
+
+		return super.buildIdentifierHelper( builder, dbMetaData );
+	}
+
+	@Override
+	public NameQualifierSupport getNameQualifierSupport() {
+		return NameQualifierSupport.CATALOG;
+	}
+
 }

hibernate-core/src/main/java/org/hibernate/tool/schema/extract/internal/AbstractInformationExtractorImpl.java

@@ -407,6 +407,9 @@ public TableInformation getTable(Identifier catalog, Identifier schema, Identifi
 	}
 
 	private Identifier getCurrentSchema(JdbcEnvironment jdbcEnvironment) {
+		if ( jdbcEnvironment.getNameQualifierSupport() == NameQualifierSupport.CATALOG ) {
+			return null;
+		}
 		if ( currentSchema != null ) {
 			return currentSchema;
 		}
@@ -428,6 +431,9 @@ private Identifier getCurrentSchema(JdbcEnvironment jdbcEnvironment) {
 	}
 
 	private Identifier getCurrentCatalog(JdbcEnvironment jdbcEnvironment) {
+		if ( jdbcEnvironment.getNameQualifierSupport() == NameQualifierSupport.SCHEMA ) {
+			return null;
+		}
 		if ( currentCatalog != null ) {
 			return currentCatalog;
 		}