Mimic SQL select * statement in SOQL using Apex

/*
* @description: A code snippet that mimics the popular Select * SQL syntax in force.com's Apex language.
*/

// Initialize setup variables
String objectName = 'Contact';  // modify as needed
String query = 'SELECT';
Map<String, Schema.SObjectField> objectFields = Schema.getGlobalDescribe().get(objectName).getDescribe().fields.getMap();

// Grab the fields from the describe method and append them to the queryString one by one.
for(String s : objectFields.keySet()) {
   query += ' ' + s + ',';
}

// Manually add related object's fields that are needed.
query += 'Account.Name,'; // modify as needed

// Strip off the last comma if it exists.
if (query.subString(query.Length()-1,query.Length()) == ','){
    query = query.subString(0,query.Length()-1);
}

// Add FROM statement
query += ' FROM ' + objectName;

// Add on a WHERE/ORDER/LIMIT statement as needed
query += ' WHERE firstName = \'test\''; // modify as needed
  
try {
        List<Contact> contacts = database.query(query);
} catch (QueryException e){
        //perform exception handling
}