What are the data access methods for the persistence layer architecture design of bank application system?

[Edit this paragraph] Design patterns and frameworks At present, reusable object-oriented software systems are generally divided into three categories: application toolboxes and frameworks, and the specific software we usually develop is applications; The API of Java belongs to the toolbox; Framework is a set of cooperative classes, which constitute a specific software reusable design. EJB(EnterpriseJavaBeans) is a framework for Java to be applied to enterprise computing. Frames usually define design parameters such as the overall structure of the application system and the relationship between objects, so that the implementer of a specific application can focus on the specific details of the application itself. The framework mainly records different design decisions in software applications. Frame emphasizes design reuse, so design patterns must be used in frame design. In addition, design patterns help to understand the frame structure. Mature frameworks usually use multiple design patterns. If you are familiar with these design patterns, there is no doubt that you will soon master the frame structure. If we ordinary developers suddenly come into contact with EJBJ2EE and other frameworks, we will find it particularly difficult to learn and master design patterns, so we should turn to them first.