Build an efficent database

I have created 2 sheets in a workbook and am trying to figure out the most efficent way to pull reports from a database/list. I'm attaching a file with examples of the 2 sheets.

What I want to accomplish is to be able to pull all of the "rows" (which in this case are people) for each Code. I want to manage a budget by Code. Each person is awarded $x dollars at the start of the year and each month spends a part of it. I want to keep track how much is left in the Code budget.

I'm looking for an efficent way to populate the yellow cells in the BudgetsFinal page. In my actual database, I have hundred of people and around 75 codes - so there is obvious duplications in last names (that I emulated with my sample sheet attached). Also, because there are so many Codes, I cannot separate each code into a different worksheet page. My assumption was that on the Budgets page, it would essentially be a new list and to view it by department I can use a filter to see just one department.

My goal is to make this entire process automated, so next year when all of the people and things change, I can update it on my database and it changes everywhere else.

I understand this is complex, so thank you for all your help and suggestions in advance!