@Override
  protected void addTo(DatabaseObject foundObject, DatabaseSnapshot snapshot)
      throws DatabaseException, InvalidExampleException {
    if (!snapshot.getSnapshotControl().shouldInclude(Column.class)) {
      return;
    }
    if (foundObject instanceof Relation) {
      Database database = snapshot.getDatabase();
      Relation relation = (Relation) foundObject;
      List<CachedRow> allColumnsMetadataRs = null;
      try {

        JdbcDatabaseSnapshot.CachingDatabaseMetaData databaseMetaData =
            ((JdbcDatabaseSnapshot) snapshot).getMetaData();

        Schema schema;

        schema = relation.getSchema();
        allColumnsMetadataRs =
            databaseMetaData.getColumns(
                ((AbstractJdbcDatabase) database).getJdbcCatalogName(schema),
                ((AbstractJdbcDatabase) database).getJdbcSchemaName(schema),
                relation.getName(),
                null);

        for (CachedRow row : allColumnsMetadataRs) {
          Column exampleColumn =
              new Column()
                  .setRelation(relation)
                  .setName(StringUtils.trimToNull(row.getString("COLUMN_NAME")));
          relation.getColumns().add(exampleColumn);
        }
      } catch (Exception e) {
        throw new DatabaseException(e);
      }
    }
  }
  @Override
  protected DatabaseObject snapshotObject(DatabaseObject example, DatabaseSnapshot snapshot)
      throws DatabaseException, InvalidExampleException {
    Database database = snapshot.getDatabase();
    Relation relation = ((Column) example).getRelation();
    if (((Column) example).getComputed() != null && ((Column) example).getComputed()) {
      return example;
    }
    Schema schema = relation.getSchema();

    List<CachedRow> columnMetadataRs = null;
    try {

      JdbcDatabaseSnapshot.CachingDatabaseMetaData databaseMetaData =
          ((JdbcDatabaseSnapshot) snapshot).getMetaData();

      columnMetadataRs =
          databaseMetaData.getColumns(
              ((AbstractJdbcDatabase) database).getJdbcCatalogName(schema),
              ((AbstractJdbcDatabase) database).getJdbcSchemaName(schema),
              relation.getName(),
              example.getName());

      if (columnMetadataRs.size() > 0) {
        CachedRow data = columnMetadataRs.get(0);
        Column column = readColumn(data, relation, database);

        if (column != null
            && database instanceof MSSQLDatabase
            && database.getDatabaseMajorVersion() >= 8) {
          String sql;
          if (database.getDatabaseMajorVersion() >= 9) {
            // SQL Server 2005 or later
            // https://technet.microsoft.com/en-us/library/ms177541.aspx
            sql =
                "SELECT CAST([ep].[value] AS [nvarchar](MAX)) AS [REMARKS] "
                    + "FROM [sys].[extended_properties] AS [ep] "
                    + "WHERE [ep].[class] = 1 "
                    + "AND [ep].[major_id] = OBJECT_ID(N'"
                    + database.escapeStringForDatabase(
                        database.escapeTableName(
                            schema.getCatalogName(), schema.getName(), relation.getName()))
                    + "') "
                    + "AND [ep].[minor_id] = COLUMNPROPERTY([ep].[major_id], N'"
                    + database.escapeStringForDatabase(column.getName())
                    + "', 'ColumnId') "
                    + "AND [ep].[name] = 'MS_Description'";
          } else {
            // SQL Server 2000
            // https://technet.microsoft.com/en-us/library/aa224810%28v=sql.80%29.aspx
            sql =
                "SELECT CAST([p].[value] AS [ntext]) AS [REMARKS] "
                    + "FROM [dbo].[sysproperties] AS [p] "
                    + "WHERE [p].[id] = OBJECT_ID(N'"
                    + database.escapeStringForDatabase(
                        database.escapeTableName(
                            schema.getCatalogName(), schema.getName(), relation.getName()))
                    + "') "
                    + "AND [p].[smallid] = COLUMNPROPERTY([p].[id], N'"
                    + database.escapeStringForDatabase(column.getName())
                    + "', 'ColumnId') "
                    + "AND [p].[type] = 4 "
                    + "AND [p].[name] = 'MS_Description'";
          }

          List<String> remarks =
              ExecutorService.getInstance()
                  .getExecutor(snapshot.getDatabase())
                  .queryForList(new RawSqlStatement(sql), String.class);
          if (remarks != null && remarks.size() > 0) {
            column.setRemarks(StringUtils.trimToNull(remarks.iterator().next()));
          }
        }

        return column;
      } else {
        return null;
      }
    } catch (Exception e) {
      throw new DatabaseException(e);
    }
  }