Made a few comments and a few corrections

Author: chernser

jdbc-v2/src/main/java/com/clickhouse/jdbc/metadata/DatabaseMetaDataImpl.java

@@ -312,12 +312,12 @@ public boolean supportsTableCorrelationNames() throws SQLException {
 
     @Override
     public boolean supportsDifferentTableCorrelationNames() throws SQLException {
-        return true; // no support
+        return false; // can be the same as table name `select * from numbers numbers limit 10`
     }
 
     @Override
     public boolean supportsExpressionsInOrderBy() throws SQLException {
-        return false;
+        return true;
     }
 
     @Override
@@ -687,7 +687,7 @@ public boolean supportsTransactions() throws SQLException {
 
     @Override
     public boolean supportsTransactionIsolationLevel(int level) throws SQLException {
-        return ConnectionImpl.TRANSACTION_NONE == level; // no transaction support
+        return Connection.TRANSACTION_NONE == level; // no transaction support
     }
 
     @Override

jdbc-v2/src/test/java/com/clickhouse/jdbc/metadata/DatabaseMetaDataTest.java

@@ -10,15 +10,13 @@
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
-import java.lang.reflect.Method;
 import java.sql.Connection;
 import java.sql.DatabaseMetaData;
 import java.sql.ResultSet;
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.sql.Types;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -172,8 +170,8 @@ public void testSupportFlags() throws Exception {
             assertEquals(dbmd.supportsColumnAliasing(), true);
             assertEquals(dbmd.supportsConvert(), false);
             assertEquals(dbmd.supportsTableCorrelationNames(), true);
-            assertEquals(dbmd.supportsDifferentTableCorrelationNames(), true);
-            assertEquals(dbmd.supportsExpressionsInOrderBy(), false);
+            assertEquals(dbmd.supportsDifferentTableCorrelationNames(), false);
+            assertEquals(dbmd.supportsExpressionsInOrderBy(), true);
             assertEquals(dbmd.supportsOrderByUnrelated(), true);
             assertEquals(dbmd.supportsGroupBy(), true);
             assertEquals(dbmd.supportsGroupByUnrelated(), true);
@@ -285,7 +283,6 @@ public void testSupportFlags() throws Exception {
             assertEquals(dbmd.supportsResultSetType(ResultSet.TYPE_FORWARD_ONLY), true);
 
             for (int type : new int[] {ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.TYPE_SCROLL_SENSITIVE} ) {
-                assertFalse(dbmd.supportsResultSetType(type));
                 assertFalse(dbmd.supportsResultSetType(type));
                 assertFalse(dbmd.ownUpdatesAreVisible(type));
                 assertFalse(dbmd.ownDeletesAreVisible(type));