Class SelectedColumnInfo
func: addColumnName(string tableName,string columnName)----add the column name to the column name set of specific table
func: getColumnNameSet(string tableName)----return the column name set for specific table
func: removeColumnName(string tableName,string columnName)----remove the column name in specific columnNameSet
Class SelectedColumnInfo func: addColumnName(string tableName,string columnName)----add the column name to the column name set of specific table func: getColumnNameSet(string tableName)----return the column name set for specific table func: removeColumnName(string tableName,string columnName)----remove the column name in specific columnNameSet