The monolithic architecture is considered to be the traditional way of building an application.
A monolithic application is usually built as a single unit and indivisible unit, generally comprising of the following layers:
A database, usually an RDBMS (relational database management system), that consists of many tables.
A server-side application that handles and serves client-side requests, retrieves and stores data from/to the database and executes business logic.
A client-side UI (User Interface) that generally consists of HTML and/or Javascript pages running on a browser.
The above layers group together to form a single logical executable. A monolithic application usually has one large codebase and lacks modularity.
If any updates are needed in the system, developers must build and deploy the entire stack at once.