fix USE statement

Author: gfunc

jdbc-v2/src/main/java/com/clickhouse/jdbc/StatementImpl.java

@@ -396,8 +396,8 @@ public boolean execute(String sql, QuerySettings settings) throws SQLException {
             //USE Database
             List<String> tokens = JdbcUtils.tokenizeSQL(sql);
             this.schema = tokens.get(1).replace("\"", "");
-            connection.getDefaultQuerySettings().setDatabase(schema);
-            LOG.debug("Changed statement schema {}", schema);
+            connection.setSchema(schema);
+            LOG.debug("Changed statement schema to {}", schema);
             return false;
         } else {
             executeUpdate(sql, settings);

jdbc-v2/src/test/java/com/clickhouse/jdbc/StatementTest.java

@@ -591,6 +591,16 @@ public void testSwitchDatabase() throws Exception {
                 assertFalse(stmt.execute("USE \"" + databaseName + "\""));
                 assertEquals(stmt.executeUpdate(createSql), 0);
             }
+            conn.createStatement().execute("USE system");
+            ResultSet rs = conn.createStatement().executeQuery("SELECT name FROM settings LIMIT 1;");
+            assertTrue(rs.next());
+            assertNotNull(rs.getString(1));
+            assertFalse(rs.next());
+            conn.createStatement().execute("USE \"" + databaseName + "\"");
+            rs = conn.createStatement().executeQuery("SHOW TABLES LIMIT 1");
+            assertTrue(rs.next());
+            assertEquals(rs.getString(1), "switchDatabaseWithUse");
+            assertFalse(rs.next());
         }
     }