can i use trigger to insert data within a time period ?

Hello sir, i want to calculate company's closing account each Saturday 12.00. In this case i need the calculation will be done automatically in database and using this trigger concept the data will be insert to each Employee's ID. Plz sir help me regarding this problem.how to solve this issue and how i will use this trigger concept? As m new to this concept.

Thanks Debasmita Baral