HHH-7009 Create new PostgreSQL 8.2 Dialect

Create dialect for Postgres 8.2 and later which supports "if exists"
in drop statements. Update resolver to return the correct dialect
version.

hibernate-core/src/main/java/org/hibernate/dialect/PostgreSQL82Dialect.java

@@ -0,0 +1,36 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * Copyright (c) 2010, Red Hat Inc. or third-party contributors as
+ * indicated by the @author tags or express copyright attribution
+ * statements applied by the authors.  All third-party contributions are
+ * distributed under license by Red Hat Inc.
+ *
+ * This copyrighted material is made available to anyone wishing to use, modify,
+ * copy, or redistribute it subject to the terms and conditions of the GNU
+ * Lesser General Public License, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this distribution; if not, write to:
+ * Free Software Foundation, Inc.
+ * 51 Franklin Street, Fifth Floor
+ * Boston, MA  02110-1301  USA
+ */
+package org.hibernate.dialect;
+
+/**
+ * An SQL dialect for Postgres 8.2 and later, adds support for "if exists" when dropping tables
+ * 
+ * @author edalquist
+ */
+public class PostgreSQL82Dialect extends PostgreSQLDialect {
+	@Override
+    public boolean supportsIfExistsBeforeTableName() {
+        return true;
+    }
+}

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

@@ -396,11 +396,6 @@ protected String getCreateSequenceString(String sequenceName, int initialValue,
 //	}
 
 
-    @Override
-    public boolean supportsIfExistsBeforeTableName() {
-        return true;
-    }
-
     public boolean supportsEmptyInList() {
 		return false;
 	}

hibernate-core/src/main/java/org/hibernate/service/jdbc/dialect/internal/StandardDialectResolver.java

@@ -45,6 +45,7 @@
 import org.hibernate.dialect.Oracle10gDialect;
 import org.hibernate.dialect.Oracle8iDialect;
 import org.hibernate.dialect.Oracle9iDialect;
+import org.hibernate.dialect.PostgreSQL82Dialect;
 import org.hibernate.dialect.PostgreSQLDialect;
 import org.hibernate.dialect.SQLServer2005Dialect;
 import org.hibernate.dialect.SQLServer2008Dialect;
@@ -85,6 +86,10 @@ protected Dialect resolveDialectInternal(DatabaseMetaData metaData) throws SQLEx
 		}
 
 		if ( "PostgreSQL".equals( databaseName ) ) {
+			final int databaseMinorVersion = metaData.getDatabaseMinorVersion();
+			if (databaseMajorVersion >= 8 && databaseMinorVersion >= 2) {
+				return new PostgreSQL82Dialect();
+			}
 			return new PostgreSQLDialect();
 		}