I got Mysql Tables: //Valid list of Mysql Tables. $tables = array('links','countries'); I got Mysql Table 'Links' Columns: //Valid list of Mysql Table Columns. $links_table_columns = array('email','domain','url','anchor','description','keyword'); I got Mysql Table 'Countries' Columns: //Valid list of Mysql Table Columns. $countries_table_columns = array('Australia','Canada','UK','USA','New Zealand'); Now, how do I add arrays within an array so by just looking at it you can tell which one is array and which ones are it's sub-arrays ? I made two attempts: 1. $tables_and_columns = array('table'=>array('links'),array('links'=>array('column'=>email,'column'=>domain,'column'=>url,'column'=>anchor,'column'=>description,'column'=>keyword))); $valid_param_keys_and_valu...