What Are Data Access Objects?

Data Access Objects (DAO) DAO is the first object-oriented interface. It is the MeringJet data shore engine ("Used by Miroft Acce") and allows VauatBasce to connect directly to other databases through ODBC like Same, directly connected to the Aces table. DAO is most suitable for single system applications or small-scale local distribution. Using DAO is an application programming interface CAPD, the DA object encapsulates the Je function of the ASS. Through the jet function, it can also access other Structured Query Language (SQL) database. 12EE developers use data access objects (DAO design patterns to separate the underlying data access logic from the high-level business logic, and implementing the DAO pattern can focus more on writing data access code. ^[1]

DAO is

Visual Basic can recognize three types of databases through the DAO and Jet engines:

The advantage of using data access objects is that the two important parts of the application are relatively simple and strictly separated, they can but should not know anything about each other, and the two can be expected to develop frequently and independently. Changing business logic can rely on the same DAO interface, and changes to the persistence logic will not affect the DAO client as long as the interface remains implemented correctly. All details stored are hidden in the rest of the application (see

Potential disadvantages of using DAO include abstraction leaks, code duplication, and abstract inversion. In particular, the abstraction of using DAO as a regular Java object will hide the high cost of each database access and may force developers to trigger multiple database queries to retrieve information that can be retrieved in a single SQL query. If an application requires multiple DAOs, people may find themselves repeating essentially the same create, read, update, and delete code for each DAO. However, it is also possible to implement a general DAO that handles common operations to avoid boilerplate code. ^[2]